Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1990-1994  (257)
  • 1985-1989
  • 1980-1984
  • 1965-1969  (12)
  • 1890-1899
  • 1992  (257)
  • 1968  (12)
  • 1895
  • Physical Chemistry  (227)
  • Kidney
Source
Material
Years
  • 1990-1994  (257)
  • 1985-1989
  • 1980-1984
  • 1965-1969  (12)
  • 1890-1899
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    The glomerular mesangium: capillary support function and its failure under experimental conditions (1992)
    Springer
    Journal of molecular medicine 70 (1992), S. 843-856 
    Details
    ISSN: 1432-1440
    Keywords: Kidney ; Glomerulus ; Mesangium ; Mesangial failure ; Electron microscopy ; Animal models
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We present a structural analysis of the ability of the biomechanical unit consisting of mesangium and glomerular basement membrane to maintain normal capillary architecture in the face of mechanical challenges due to high intraglomerular pressures. Capillary support function may be considered in terms of the stabilization of local form (development of wall tension against capillary dilation) and global form (centripetal fixation of capillary loops to maintain higher order form). The pathologic consequences of the loss of this support are illustrated by way of experimental models of mechanical mesangial failure. Such failure may express itself as mesangial widening, increased transmesangial macromolecule “traffic,” ballooning of capillary segments, and unfolding of capillary loops. Mechanisms are described by which these structural changes may lead to segmental glomerular sclerosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180755
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Carvedilol and the kidney (1992)
    Springer
    Journal of molecular medicine 70 (1992), S. S127 
    Details
    ISSN: 1432-1440
    Keywords: Carvedilol ; Kidney ; Hypertension ; Renal hemodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Antihypertensive drugs have differing effects on renal hemodynamics, tubular function, plasma electrolytes, and hormonal responses. Nonselective β-blockers without intrinsic sympathomimetic activites, such as propranolol, have been reported to reduce renal blood flow and to cause a modest decrease in glomerular filtration rate. Carvedilol is a new multiple action agent displaying nonselective β-blockade without intrinsic sympathicomimetic activity, α1-adrenoceptor blockade (probably responsible for its vasodilator activity), and possibly also calcium antagonist properties. The presence of these different pharmacodynamic properties results in a different effect on the kidney as compared with, e.g., propranolol. In the dog, intrarenal infusion of carvedilol resulted in a renal vasodilator response with preservation of renal blood flow and without inducing sodium retention; in contrast, propranolol induced a renal vasoconstrictor response and sodium retention in this model. A renal vasodilator response to carvedilol was also reported in spontaneously hypertensive rats (SHR) and in DOCA-salt SHR. In contrast to labetalol, i.v. infusion of hypotensive doses of carvedilol in conscious SHR did not cause sodium retention. Carvedilol was effective in controlling hypertension and preserving renal function in a rat model of progressive hypertensive renal disease. In patients with essential hypertension, carvedilol was reported to reduce renal vascular resistance in the presence of reduced perfusion pressure, allowing for normal renal autoregulation of renal blood flow. Although a small reduction in glomerular filtration rate was seen after acute administration, renal function was preserved during chronic treatment. It is concluded from these studies that renal perfusion and renal function are well maintained during acute and chronic treatment with carvedilol. The compound does not appear to cause sodium retention, and preliminary animal test data suggest the possibility of a renoprotective effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00207623
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Renal potassium bicarbonate release in humans exposed to an acute volume load (1992)
    Springer
    Journal of molecular medicine 70 (1992), S. 692-697 
    Details
    ISSN: 1432-1440
    Keywords: Kidney ; Urine concentration ; Volume regulation ; Potassium ; Bicarbonate ; Aldosterone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cells of the renal medulla regulate their volume by transmembrane ion movements when exposed to large changes in osmolality. Since renal cells in culture release KHCO3 in response to hypotonic stress [11], we investigated the effect of an acute water load on urinary KHCO3 excretion in 5 healthy individuals. Water diuresis was induced by the ingestion of 1.51 hypoosmolal fluid (22 mosm/kg H2O) over 15 min. The rate of urinary volume excretion increased from an initial value of 1.4 ml/min to 9.3 ml/min after 75 min. Urinary osmolality dropped from an initial value of 940±32 mosm/kg H2O to 74±4 mosm/kg H2O (n = 5). The decrease of osmolality was accompanied by the transient release of potassium and bicarbonate. Peak values of KHCO3 excretion were observed between 30 and 45 min after the onset of the experiment corresponding to the drop of urinary osmolality. The magnitude of renal potassium release correlated significantly (r=0.93; P 〈 0.05) with endogenous plasma aldosterone concentrations measured prior to the experiment in the 5 volunteers. We conclude that medullary epithelial cells release KHCO3 when exposed to hypotonic stress. The volume regulatory response is upregulated by aldosterone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180288
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Caries susceptibility and renal excretion of calcium (1992)
    Springer
    Journal of molecular medicine 70 (1992), S. 735-739 
    Details
    ISSN: 1432-1440
    Keywords: Kidney ; Calcium ; Phosphate ; Sodium ; Caries
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Clearance studies were performed for 2 days in two groups of age-matched young female volunteers: those with low caries prevalence and those with high caries prevalence. Both groups were kept on a low-calcium diet for 1 week and received 0.5 g calcium at the beginning of the second day. In both groups, glomerular filtration rate, urinary flow rate and renal excretions of sodium, calcium, and phosphate were subject to significant circadian variations. In both groups the administration of calcium led to a significant increase in renal excretion of sodium and calcium and a significant decrease in that of phosphate. On the first day, calcium excretion was significantly greater in those with low caries prevalence than in those with high caries prevalence, pointing to altered calcium homeostasis in this group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180739
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Activation of β2-adrenoceptors by isoprenaline and adrenaline enhances noradrenaline release in cortical kidney slices of young spontaneously hypertensive rats (1992)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 345 (1992), S. 25-32 
    Details
    ISSN: 1432-1912
    Keywords: 3H-noradrenaline release ; SHR ; Kidney ; Prejunctional β-adrenoceptors ; Adrenaline ; Isoprenaline ; cAMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the present study was to investigate β-adrenoceptor modulation of noradrenaline release from sympathetic nerves in superfused cortical kidney slices of 4-week-old spontaneously hypertensive rats (SHR) and age-matched controls (WKY). After preincubation with 3H-noradrenaline the kidney slices were electrically stimulated in superfusion chambers. The stimulation induced (S-I) outflow of radioactivity was mainly composed of unmetabolized 3H-noradrenaline in both strains and thus taken as an index of noradrenaline release. There was a frequency-dependent (1.25–20 Hz) increase in the S-1 outflow of radioactivity. At all stimulation frequencies tested S-I outflow of radioactivity was similar or even slightly lower in SHR than in WKY kidney slices in either the absence or presence of cocaine (10 μmol/l). The non-selective β-adrenoceptor agonists isoprenaline (0.l gmol/1) and adrenaline (0.01 and 0.1 μmol/l) enhanced S-I outflow of radioactivity. The facilitatory effects of isoprenaline (0.1 μmol/l) and adrenaline (0.1 μmol/l) were blocked by the selective β2-adrenoceptor antagonist ICI 118551 (0.1 μmol/l) but not by the selective β1-adrenoceptor antagonist atenolol (0.3 μmol/l). The cell-permeable CAMP analogue 8-bromo-cAMP (300 μmol/l) enhanced S-1 outflow of radioactivity to a similar extent in both SHR and WKY kidney slices. A combination of 8-bromo-cAMP (300 μmol/l) and adrenaline (0.1 μmol/l) did not enhance S-1 outflow of radioactivity to a greater extent than 8-bromo cAMP (300 μmol/l) alone in both strains. However, the facilitatory effects of isoprenaline (0.1 μmol/l) and adrenaline (0.1 μmol/l) but not that of adrenaline (0.01 μmol/l) were significantly greater in SHR than in WKY. The results suggest that stimulation of prejunctional β2-adrenoceptors by adrenaline even in the absence of a-adrenoceptor blockade enhances noradrenaline release in kidney cortex of young SHR and WKY. This β2-adrenoceptor mediated effect may possibly be dependent on cAMP formation. The greater facilitatory effects of isoprenaline (0.1 μmol/l) and adrenaline (0.1 μmol/l) in SHR as compared to WKY are in accord with receptor binding studies which show a higher density of β2-adrenoceptors in SHR than in WKY kidney cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175465
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Influence of antihypertensive therapy on renal function (1992)
    Springer
    Journal of molecular medicine 70 (1992), S. S120 
    Details
    ISSN: 1432-1440
    Keywords: Hypertension ; Kidney ; Antihypertensive drugs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Antihypertensive therapy influences kidney function by different mechanisms depending on the mode of action of the drug used. The GFR is improved by calcium entry blockers and ACE inhibitors, unaffected by vasodilators, α-blockers and centrally acting sympatholytics and impaired by β-blockers. The same is true for renal blood flow and is due to changes of renal vascular resistance. Renal sodium excretion is impaired mostly by vasodilators, by α-blockers, sympatholytics and β-blockers; in contrast, calcium entry blockers and ACE inhibitors acutely induce natriuresis. The RAAS is stimulated by vasodilators, unaffected by α-blockers and sympatholytics and suppressed by β-blockers. Plasma catecholamines are stimulated by vasodilators and suppressed by centrally acting sympatholytics and unaffected by the others. Induction of acute renal functional impairment is reported for ACE inhibitors under conditions of compromised renal perfusion pressure such as in renal artery stenosis. These data from the literature reviewed are supported by our own experimental data on sodium balance under different drugs and micropuncture data in experimental renal artery stenosis. To achieve effective antihypertensive treatment with a low profile of side effects, careful monitoring of renal function seems to be mandatory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00207622
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Ca2+ uptake by endoplasmic reticulum of renal cortex. II. Effects of uninephrectomy and parathyroidectomy (1992)
    Springer
    Calcified tissue international 51 (1992), S. 42-47 
    Details
    ISSN: 1432-0827
    Keywords: Kidney ; Endoplasmic reticulum ; Calcium ; In vivo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Calcium uptake by the endoplasmic reticulum (ER) is important for cellular calcium homeostasis, yet its regulation in nonmuscle cells is poorly understood. We reported that Ca2+ uptake by a light fraction of canine renal cortical ER (LER) is stimulated by protein kinase C in vitro. Here we describe conditions in vivo that stimulated renal cortical LER Ca2+ uptake. Thirty minutes after contralateral nephrectomy in the dog, 45Ca2+ uptake into renal cortical LER was increased 42% above control LER. There was no difference in LER Ca2+ uptake 24 hours after uninephrectomy. Acute denervation did not reproduce the increase in LER 45Ca2+ uptake seen at 30 minutes after uninephrectomy, nor did prior thyroparathyroidectomy abolish it. Forty-eight hours after thyroparathyroidectomy, 45Ca2+ uptake activity into renal cortical LER was decreased ≈sevenfold. In a proximal tubular cell line (LLC-PK1), 30-minute incubation with 12-O-tetradecanoylphorbol-13-acetate doubled 45Ca2+ uptake into a nonmitochondrial pool. Pretreatment with epidermal growth factor halved ER Ca2+ uptake, whereas insulin-like growth factor and growth hormone, alone or in combination, had no effect. Our data suggest that Ca2+ uptake into renal cortical ER is stimulated acutely during compensatory renal growth, perhaps through protein kinase C, and is stimulated chronically by parathyroid hormone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296216
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Arteries and veins formed within renal vessels: a previously neglected observation (1992)
    Springer
    Virchows Archiv 420 (1992), S. 301-304 
    Details
    ISSN: 1432-2307
    Keywords: Kidney ; Blood vessels ; Arterialisation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An abnormality of blood vessels was noted in a biopsy of a renal transplant. This took the form of apparent development of a new artery inside and concentric with the old, with elastic laminae and a muscular media, separated from the old internal elastic lamina by poorly cellular tissue. In a systematic study of material from another 119 renal transplants, 13 nephrectomy specimens for chronic pyelonephritis and hydronephrosis, 28 renal biopsies showing interstitial nephritis, and 18 renal biopsies showing small vessel vasculopathy of accelerated hypertensive type, similar arterial changes were seen in another 10 renal transplants that showed chronic vascular rejection, 1 case of chronic interstitial nephritis, and 3 cases of vasculopathy, 2 with accelerated hypertension and 1 with systemic sclerosis. One renal transplant also showed apparent development of new muscular veins inside old veins. Immunohistological study for smooth muscle actin confirmed that the apparently new arterial and venous structures contained smooth muscle cells. The arterial abnormality may be called arterialisation of intrarenal arteries. This change appears to be not rare, is distinctive, and has scarcely been previously recognised or reported as a response of intrarenal blood vessels to damage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600208
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The renin-secreting cell and the glomerular peripolar cell in renal artery stenosis and Addison's disease (1992)
    Springer
    Virchows Archiv 420 (1992), S. 533-537 
    Details
    ISSN: 1432-2307
    Keywords: Peripolar cell ; Renin ; Juxtaglomerular apparatus ; Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The glomerular peripolar cell may be a secretory component of the juxtaglomerular apparatus. To investigate this hypothesis we studied kidneys with the renin-angiotensin system activated by two different stimuli in order to compare the responses of peripolar cells and renin-secreting cells. We examined 10 human kidneys, removed for renal artery stenosis and 11 autopsy cases of Addison's disease with appropriate controls. We counted granulated peripolar cells in serial paraffin-embedded sections and renin-containing cells were quantified using an immunoperoxidase technique with an antiserum to human renin. There was a five-fold increase in the number of renin-containing cells in both renal artery stenosis and in untreated, but not in treated, Addison's disease. Peripolar cells were increased in number in three cases of renal artery stenosis, but were unaltered in both treated and untreated Addison's disease. Therefore, neither a reduction in renal perfusion pressure (renal artery stenosis), nor sodium depletion (Addison's disease) consistently affect peripolar cells in humans. These findings do not support the hypothesis that the peripolar cell is part of the juxtaglomerular apparatus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600259
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Analysis of kidney volume growth during the fetal period in humans (1992)
    Springer
    Urological research 20 (1992), S. 271-274 
    Details
    ISSN: 1434-0879
    Keywords: Kidney ; Fetal kidney ; Renal volume ; Renal growth ; Fetal urology ; Renal anomalies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The growth of fetal kidney volume was studied in 290 specimens taken from 145 fresh human fetuses (85 males and 60 females) with gestational age ranging from 13 to 36 weeks postconception (WPC). Normative equations and curves of the growth of renal volume were obtained for male and female fetuses and for the whole sample in the second trimester (13–24 WPC) and in the third trimester (25–36 WPC) of gestation. There was no difference between the growth in volume of the right and left kidneys. Fetal kidney volume increases with a more intense rhythm in the early fetal period (13–24 WPC). During the second trimester, there was no difference between the values for renal volume of male and female fetuses. In the third trimester, male fetuses had renal volumes significantly greater than the female fetuses. The normative parameters of renal volume could have practical applications in detection and monitoring of renal anomalies in fetal and perinatal urology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300257
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Effect and distribution of intravenously injected 125I-endothelin-1 in rat kidney and lung examined by electron microscopic radioautography (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 87-96 
    Details
    ISSN: 1432-0568
    Keywords: Kidney ; Endothelium ; Glomerular mesangium ; Lung ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The morphological effect of endothelin-1 (ET-1) and the distribution of endothelin-binding sites on the kidney and lung was investigated ultrastructually by intravenous injection of [125I]-ET-1 into rats. About 10% decrease of the diameter of glomeruli was observed at 10 min after the injections of ET-1 or [125I]-ET-1 (1.3–2.4 nmole/kg). When localization of [125I]-ET-1 in the kidney was examined by light and electron microscopic radioautography, silver grains were preferably localized on the fenestrated endothelial cells of glomeruli and peritubular capillary endothelial cells. Some grains were also localized on the interdigitating processes of urinary tubules. Quantitative analysis of silver grains in the glomeruli showed that 83% of grains were located on the fenestrated endothelial cells, 12% on the podocytes of visceral cells, and 5% on mesangial cells at 10 min. After 60 min, 50% of silver grains were incorporated into the cytoplasm of fenestrated endothelial cells. In contrast to glomeruli, silver grains were rare on the arteries and large arterioles. However, a few silver grains were often observed on the smooth muscle cells of small arterioles (8–20 μm in diameter). In the lung, 70% of silver grains were located on the alveolar capillary endothelial cells. These results indicate the abundance of ET receptors on the glomerular fenestrated endothelium, peritubular fenestrated endothelium and alveolar capillary endothelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213604
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Development of the metanephros in the chick: maturation of glomerular size and nephron length (1992)
    Springer
    Anatomy and embryology 185 (1992), S. 291-297 
    Details
    ISSN: 1432-0568
    Keywords: Kidney ; Nephron development ; Chick
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the avian kidney three nephron types may be identified: mammalian-type nephrons with long (MTN-I) and short (MTN-II) loops of Henlé, and reptilian-type nephrons (RTN). By the method of microdissection the maturation of the nephrons of domestic fowl kidney has been studied. From the 14th day of incubation it is possible to isolate the MTN-I which appear first; all three nephron types may be isolated after 18 days of incubation. The thin limb of Henlé's loop in MTN-I appears after hatching, and the length of this segment in 1-day-old chicks is 0.1–0.13 mm. In 60-day-old chicks its length has approximately doubled. The transition of the thin segment to the thick segment is situated in the descending part of Henlé's loop. In the course of development, the relative length of all nephron segments in MTN-I increases uniformly, while in MTN-II and in RTN the relative length of the proximal and distal convoluted tubules increases. At all stages of development, MTN-I are the longest among the three groups of nephrons and have the largest glomeruli. The comparison between developing avian and mammalian kidneys shows great similarities in the process of maturation in analogous nephron types in these two classes of vertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00211828
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Structural relationships between the endothelial actin system and the underlying elastic layer in the distal interlobular artery of the rat kidney (1992)
    Springer
    Anatomy and embryology 186 (1992), S. 467-476 
    Details
    ISSN: 1432-0568
    Keywords: Artery ; Endothelial cell ; Stress fiber ; Elastic fiber ; Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The structure of the intracellular actin filaments and the extracellular matrices was studied in the distal interlobular arteries in the rat kidney, employing three different morphological techniques, including rhodamin-phalloidin staining of cryosections, resorcin-fuchsin staining of paraffin sections, and a cold dehydration procedure for electron microscopy. The endothelial cells possess longitudinally running stress fibers. The inner elastic layer is composed of meshworks of elastic fibers encompassing numerous pores. The smooth muscle cells containing abundant actin filaments are arranged circumferentially around the vascular axis. The endothelial stress fibers are found mainly in the basal half of the endothelial cells, and anchor onto the basal cell membranes. The elastic meshworks send off longitudinal branch fibers to contact the endothelial cell membranes at the anchoring sites of stress fibers. In addition circumferential branches run toward the smooth muscle cells. The functional significance of the intracellular contractile apparatus and the extracellular tensile component in small arteries was discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00185460
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Transient increase in renal insulin-like growth factor binding proteins during initial kidney hypertrophy in experimental diabetes in rats (1992)
    Springer
    Diabetologia 35 (1992), S. 589-593 
    Details
    ISSN: 1432-0428
    Keywords: Kidney ; hypertrophy ; insulin-like growth factors ; insulin-like growth factor binding proteins ; streptozotocin ; diabetes ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The insulin-like growth factors, insulin-like growth factor I and insulin-like growth factor II are bound to six distinct classes of insulin-like growth factor binding proteins (IGFBPs) in the circulation and in extracellular fluids. Diabetic renal hypertrophy is preceded by a transient increase in kidney insulin-like growth factor I suggestive of a renotropic function for insulin-like growth factor I. In order to examine a possible involvement of IGFBPs in initial diabetic kidney growth and in kidney insulin-like growth factor I accumulation, we studied rat kidney IGFBPs by ligand blotting during the first 4 days after induction of diabetes. Six distinct bands were identified in kidney and liver tissue with apparent molecular weight values of 38–47 (doublet), 34, 30, 24 and 20 kDa. The 38–47 kDa doublet band probably corresponds to the insulin-like growth factor binding subunit of IGFBP-3, the 24 kDa band to IGFBP4 and the 30 kDa band to IGFBP-1 and/or IGFBP-2, as these IGFBPs in rats have similar molecular weight. In untreated diabetic rats a transient increase in the kidney 30 kDa band was demonstrable 24 h after induction of diabetes with a maximal rise (two-fold) after 48 h, followed by a decrease to baseline values after 4 days. In untreated diabetic rats the 38–47 kDa doublet band also increased (two-fold) in kidney during the first 2 days after induction of diabetes, followed by a subsequent decrease. Insulin-treatment prevented both the increase in the 30 kDa and in the 38–47 kDa bands. Kidney weight in untreated diabetic rats increased by 26 % after 4 days. In conclusion, the present study shows a transient increase in the 30 kDa and the 38–47 kDa IGFBP species in hypertrophying diabetic kidneys, contemporarily with the previously described transient increase in extractable kidney insulin-like growth factor I content. These findings support the concept that IGFBPs may be involved in the action of insulin-like growth factor I and possibly in the diabetic kidney insulin-like growth factor I accumulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00400489
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Renal arteries: anatomic study for surgical and radiological practice (1992)
    Springer
    Surgical and radiologic anatomy 14 (1992), S. 113-117 
    Details
    ISSN: 1279-8517
    Keywords: Kidney ; Renal artery ; Multiple renal arteries ; Renal transplantation ; Renal angiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé La vascularisation artérielle du rein a été analysée à partlr de 266 dissections provenant de 133 sujets d'anatomie. Les résultats anatomiques sont les suivants: une seule artère hilaire est présente dans 53,3% des cas; une artère hilaire associée à une branche polalre supérieure extrahilaire dans 14,3% des cas; deux artères hilaires dans 7,9% des cas; trois artères hilaires dans 1,9% des cas; une artère polaire supérieure dans 6,8% des cas; une artère polaire inférieure dans 5,3% des cas; enfin d'autres variations dans 8,5% des cas. Sont envisagées les applications urologiques et radiologiques de ces constatations dans la transplantation rénale, la pathologie hypertensive d'origine rénale, la traumatologie rénale, la radiologie interventionnelle, la chirurgie conservatrice et l'oncologie.
    Notes: Summary The renal arterial supply was analyzed in 266 kidneys dissected from 133 fixed adults subjects. The anatomical findings are presented: 1 hilar artery in 53.3% of the cases, 1 hilar artery with 1 superior pole extra-hilar branch in 14.3%, 2 hilar arteries in 7.9%, 3 hilar arteries in 1.9%, superior polar artery in 6.8%, inferior polar artery in 5.3% and other variations in 8.5%. The urological and radiological implications of these findings in kidney transplantation, renovascular hypertension, renal trauma, interventional radiology, conservative surgery and oncologic surgery are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01794885
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Ca2+ uptake by endoplasmic reticulum of renal cortex. I. Ionic requirements and regulation in vitro (1992)
    Springer
    Calcified tissue international 51 (1992), S. 35-41 
    Details
    ISSN: 1432-0827
    Keywords: Kidney ; Endoplasmic reticulum ; Calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A subcellular fraction enriched in cytochrome c reductase (7.9-fold) and relatively de-enriched (0.64-fold) in Na+/K+-ATPase was prepared from canine kidney cortex by sucrose density gradient ultracentrifugation. It was shown by electron microscopy to consist primarily of a light fraction of endoplasmic reticulum (LER). LER vesicles displayed ATP-dependent 45Ca2+ uptake that was insensitive to 10 mM KCN or NaN3, and was promptly released by 20 μM A23187 or ionomycin. Inositol-1,4,5-trisphosphate (IP3) appeared to produce a time-dependent release of 45Ca2+. Vanadate inhibited 45Ca2+ uptake with a Ki≈0.3 mM, further suggesting that the activity resided in the ER rather than the plasma membrane. 45Ca2+ uptake by LER, at 5 μM total [Ca2+], displayed a strong dependence on divalent cations (Mg2+〉Co2+〉Mn2+≫Ba2+≥Cd2+≥Sr2+, present at 2 mM) as well as on monovalent cations (Na+≥K++Na+ 〉K+〉Li+〉choline+), and anions (Cl-〉acetate-≥NO3 -≥F-〉H2PO4 -≫gluconate-≥oxalate=≫SO4 =). It had a fairly narrow pH optimum (7.25–7.50). Preincubation (10 min) of LER vesicles with 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulated LER Ca2+ uptake; this effect was enhanced in the presence of renal cytosol [5% (vol/vol)]. However, Ca2+ uptake was not affected by preincubation with dibutyryl cyclic AMP, calmodulin, or 1,25-(OH)2-vitamin D3, either in the absence or presence of renal cytosol. Thus, the Mg2+-ATP dependent 45Ca2+ uptake activity of this canine renal cortical LER fraction displays modulation by IP3, TPA, and pH that appears to be physiologically relevant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296215
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Pharmacokinetics and tolerance of Gd-DOTA (DOTAREM) in healthy volunteers and in patients with chronic renal failure (1992)
    Springer
    European radiology 2 (1992), S. 326-329 
    Details
    ISSN: 1432-1084
    Keywords: Gd-DOTA ; Contrast media ; Kidney ; Renal failure ; Pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this study was to assess the pharmacokinetics and tolerance of Gd-DOTA (DOTAREM) in non-dialysed patients with chronic renal failure. Eight patients with chronic renal failure (creatinine clearance between 10 and 60 ml/min) and four healthy volunteers were given i.v. Gd-DOTA (0.1 mmol/kg). Blood and urine samples were collected. Gd-DOTA tolerance was also studied (vital signs, biological parameters, adverse reactions). In healthy volunteers, Gd-DOTA was rapidly distributed in the extracellular space and almost totally eliminated in the urine (glomerular filtration, 93.3±4.7% of the dose 24 h post injection). In patients with chronic renal failure, a delayed and almost total urinary elimination observed with a correlation between Gd-DOTA clearance and plasma creatinine clearance (r = 0.964). Tolerance was good with no significant modification of renal function or other parameters. These results confirm previous studies and indicates that DOTAREM can be used safely for patients with chronic renal failure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175436
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Ethical and psychological aspects of living donorship and life with a donated organ (1992)
    Springer
    European journal of pediatrics 151 (1992), S. S76 
    Details
    ISSN: 1432-1076
    Keywords: Ethics ; Psychology ; Living organ transplantation ; Paediatrics ; Kidney
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract There is far-reaching consent in the literature that public and consensual agreements on the basics of the different aspects of medical ethics are inalienable before the instigation of any innovative transplant procedure. In the case of a certain method and/or of an individual patient, however, the ultimate ethical evaluation can most likely never be entirely complete before this application. Ethical evaluation depends on the actual criteria used, the present knowledge regarding the risk-benefit-balance as well as on the ethical evaluation of the patient's and his family's own feelings and expectations which are not entirely conscious. In relation to the so-called “fundamental and constant ethical guidelines” and under a psychological perspective potential, ethical conflict constellations are presented which have to be dealt with in the process of ethical and psychological evaluation before living organ transplantation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02125808
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Cell proliferation induced in the kidneys and livers of rats and mice by short term exposure to the carcinogen p-dichlorobenzene (1992)
    Springer
    Archives of toxicology 66 (1992), S. 503-507 
    Details
    ISSN: 1432-0738
    Keywords: Kidney ; Liver ; Cell proliferation ; Rat ; Mouse ; p-Dichlorobenzene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cell proliferation in the kidneys and livers of rats and mice exposed short-term to p-dichlorobenzene (p-DCB) was evaluated by immunohistochemical measurement of bromodeoxyuridine (BrdU) incorporation into nuclei of DNA-synthesizing cells. p-DCB was given by gavage at two doses up to 600 mg/kg body weight for 4 days. The cumulative fraction of proliferating cells was increased in the proximal tubule epithelial cells of male rats at the high dose, but not at the low dose nor in females at either dose using gamma-glutamyl transferase reaction to identify tubular cells. Also, no increase in cell proliferation was found in mouse kidneys. The fractions of proliferating cells in the livers of rats and mice of both sexes were also increased. The increased cell proliferation in only male rat kidney and in the livers of mice of both sexes correlates with the reported carcinogenic effects of p-DCB in those tissues. However, the finding that p-DCB also induced cell proliferation in the livers of rats of both sexes, which were not a site of p-DCB-induced tumors in bioassays, and in female mice at the low dose, which was not affected by an increase in tumors, reveals a lack of concordance and indicates that acute induction of cell proliferation is not sufficient to lead to carcinogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01970676
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Renal transplantation in infants, a therapeutic option? (1992)
    Springer
    European journal of pediatrics 151 (1992), S. S13 
    Details
    ISSN: 1432-1076
    Keywords: Kidney ; Transplantation ; Infant ; Uremia ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Renal transplantation is widely accepted as the treatment of choice for endstage renal failure in childhood. Since dialysis is regularly applied to infants with renal failure, the question logically arises, can infants also receive renal transplants and what are the outcomes? A review of the literature and the clinical experience at the University of Minnesota supports the performance of renal transplantation in infancy. Present patient and graft survival rates for infants are indistinguishable from those of older children. While living adult donors are preferred, adult cadaveric kidneys have also been successfully transplanted. Following successful transplantation, the infants have generally enjoyed “catch-up” growth and accelerated psychomotor development. While there may be problems related to fluid and electrolyte balance in these smallest patients, the majority of the problems encountered mirror those seen in any child undergoing transplantation. Renal transplantation is regularly successful in infancy and should be considered an integral component of the therapy for any child with chronic renal failure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02125797
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Sodium-taurine cotransport in reptilian renal brush-border membrane vesicles (1992)
    Springer
    Pflügers Archiv 421 (1992), S. 168-175 
    Details
    ISSN: 1432-2013
    Keywords: Taurine ; Kinetic ; Stoichiometry ; Amino acid transport ; β-Amino acid ; Membrane vesicle ; Kidney ; Sodium-coupled transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The coupled transport of Na+ with taurine into snake renal brush-border membrane vesicles (BBMV) was studied using 5-s uptake conditions. Taurine transport into snake renal BBMV involved two parallel processes, one saturable (Na+-dependent) and one (Na+-independent) that behaved like passive diffusion. Below 1 mM taurine concentration, the Na+-dependent system accounted for 60% of total taurine uptake. Over both low (0.001–0.80 mM) and high (0.8–5.0 mM) taurine concentration ranges, the Na+-dependent taurine uptake within each range showed Michaelis-Menten kinetics, suggesting the presence of two independent saturable Na+-dependent transport systems for taurine. The high-affinity, low-capacity system saturated above 100 μM with a K m of 71.4±45.7 μM and a maximum velocity (V max) of 21.9±3.77 pmol (mg protein)−1 (5 s)−1. The low-affinity, high-capacity system saturated above 1 mM, with a K m of 1.11±0.63 mM and a V max of 252±47 pmol (mg protein)−1 (5 s)−1. The stoichiometric relationship between external Na+ concentration and taurine uptake (at 10 μM) by the high-affinity BBMV transport system was examined by the activation method under short-circuited conditions. The 5-s rate of taurine transport was a sigmoid function of increasing extravesicular Na+ concentration. Kinetic analysis of the interaction of Na+ with the high-affinity taurine transport system suggested that 3 Na+ ions (3.2±0.7) may be involved with 1 taurine molecule in the transport event. The data suggest the presence of a highly efficient and high-affinity reabsorptive taurine transport system on the luminal membrane of the kidney of the garter snake, a species that can secrete taurine in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00374824
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Distribution of histamine in the rat kidney during pregnancy and development (1992)
    Springer
    Cell & tissue research 267 (1992), S. 233-239 
    Details
    ISSN: 1432-0878
    Keywords: Development, ontogenetic ; Kidney ; Glomerulus ; Distal convoluted tubule (DCT) ; Histamine ; Immunohistochemistry ; Hybridization, in situ ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An antiserum against conjugated histamine and two oligonucleotide probes that detect the mRNA encoding L-histidine decarboxylase (HDC) involved in histamine synthesis were used to study the appearance of histamine and its location in the kidneys of fetal, newborn and young postnatal rats and in the kidneys of pregnant rats. On embryonic days 16 and 18 (E16 and E18), some HA-immunoreactive (HA-ir) cells were found within the largest S-shaped bodies. Histamine was found to appear rapidly between the 18th and 20th embryonic days in the convoluted tubules of the kidneys. On postnatal day 0 (P0), the distal convoluted tubules and collecting ducts exhibited bright fluorescence, the intensity of which decreased quickly so that it was faint on day P4 and absent at later stages. In kidneys of pregnant rats HA-ir was found in the epithelium of both the Bowman's capsule, collecting ducts and in a few cells within the tubules. Nonuniform HA-ir was also detected within glomeruli. No evidence for the presence of L-histidine decarboxylase mRNA in kidneys of fetuses or pregnant rats was seen. It is concluded that distinct structures in the developing rat kidney contain histamine during a period around birth from day E20 to day P4. In the pregnant rat, the epithelium that is in direct contact with the urine flow is immunoreactive for histamine from day 16 to 20 of pregnancy. The results suggest that histamine is not synthesized locally in the kidneys but rather originates from other tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302960
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Total numbers of glomeruli and individual glomerular cell types in the normal rat kidney (1992)
    Springer
    Cell & tissue research 270 (1992), S. 37-45 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Glomerulus ; Stereology ; Morphometry ; Disector ; Quantitative methods, structural ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Alterations in numbers of glomeruli and glomerular cells occur in various renal disorders. Although values for these parameters have previously been reported for several species, the estimates have often been biased due to assumptions regarding glomerular and/or nuclear size and shape. Other studies have used tedious serial-section reconstruction methods. In the present study, unbiased stereological methods were used to estimate total numbers of glomeruli and individual glomerular cell types in normal rats. The kidneys of seven adult Sprague-Dawley rats were perfused with 4% paraformaldehyde and 1% glutaraldehyde in phosphate buffer and embedded in either glycolmethacrylate (for light microscopy, LM) or Epon/Araldite (for transmission electron microscopy, TEM). Total glomerular number was estimated using an LM physical disector/fractionator combination; the total number of cells per average glomerulus was estimated using an LM optical disector/ Cavalieri combination; and TEM physical disectors were used to count individual cell types. The normal rat kidney was found to contain 31764±3667 (mean±SD) glomeruli. An average glomerulus contained 674±129 cells, of which 181±53 were epithelial cells (podocytes), 248±53 were endothelial cells, and 245±45 were mesangial cells. An average renal corpuscle contained 117±27 parietal epithelial cells. Following sectioning and staining, less than 6.5 h was needed to obtain the above estimates for a single animal, with coefficients of variation (SD as a percent of the mean) ranging from 10% to 25%. The unbiased stereological methods used in the present study constitute an unbiased, precise and cost-efficient set of quantitative tools for assessing glomerular morphology in health and disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00381877
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Confocal microscopic and other observations on the distal end of the thick limb of the human loop of Henle (1992)
    Springer
    Cell & tissue research 267 (1992), S. 11-16 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Distal tubule ; Tamm-Horsfall protein ; Cytokeratin ; Immunohistochemistry ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Various antibodies and lectins were used in a histological study of the human renal tubule, particularly of the distal end of the thick limb of the loop of Henle. The thick limb, identified by antibody to Tamm-Horsfall protein, ended abruptly, either at the macula densa or at a variable distance after it. At this point there was an abrupt change in cell size. Confocal microscopy and other techniques showed that this point marked an abrupt beginning of tubular staining by the cytokeratin antibody PKK 2 and the lectin UEA 1, with an abrupt end of staining by the lectin DBA. Distal from this point, there were gradual changes in staining of the tubule by various reagents including other antibodies to cytokeratins. These structural findings suggest that there is a fundamental change in the tubule at the end of the thick limb. The abrupt end to the thick limb in man resembles that seen in the rat and the rabbit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318686
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Immunohistochemical localization of transthyretin in glomerular peripolar cells of newborn sheep (1992)
    Springer
    Cell & tissue research 267 (1992), S. 193-197 
    Details
    ISSN: 1432-0878
    Keywords: Transthyretin ; Kidney ; Peripolar cells ; Sheep, newborn
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Purified transthyretin has been isolated from sheep serum. Antiserum raised against this protein has been used with an indirect immunoperoxidase histochemical technique to identify transthyretin in newborn lamb kidney tissue. Transthyretin was found in proximal tubule cells and in glomerular peripolar cells. Preabsorption studies using purified transthyretin protein indicate that the immunoreactivity of the antiserum is specific to transthyretin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318704
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Non-granulated peripolar cells exist in the rat glomerulus (1992)
    Springer
    Cell & tissue research 268 (1992), S. 567-570 
    Details
    ISSN: 1432-0878
    Keywords: Peripolar cell ; Glomerulus ; Kidney ; Cytoplasmic granules ; Scanning electron microscopy ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The peripolar cell is a unique cell type in the mammalian glomerulus. Peripolar cells are said to be identifiable during light microscopy by their cytoplasmic granules and by their position at the vascular pole; and during scanning electron microscopy by their distinctive surface morphology. We used both techniques to count peripolar cells in 6 normal rat kidneys. Scanning microscopy revealed that 55(±5)% of glomeruli contained at least one peripolar cell whereas light microscopy revealed granulated peripolar cells in only 4(±2)% of glomeruli. Vascular poles which contained peripolar cells previously identified by scanning were then examined by light and by transmission electron microscopy. Serial sections through these peripolar cells demonstrated the absence of cytoplasmic granules. Our observations suggest that the majority of peripolar cells in the rat contain no granules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319164
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    The structure and biochemistry of the vacuolar H+ ATPase in proximal and distal urinary acidification (1992)
    Springer
    Journal of bioenergetics and biomembranes 24 (1992), S. 351-359 
    Details
    ISSN: 1573-6881
    Keywords: Kidney ; collecting tubule ; intercalated cells ; urinary acidification ; acid-base balance ; proton pump ; V-ATPase ; regulatory proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Vacuolar H+ ATPases participate in renal hydrogen ion secretion in both the proximal and distal nephron. These plasma membrane forms of the vacuolar H+ ATPase are regulated physiologically to maintain the acid-base balance of the organism. Proton transporting renal cells have requirements for constitutive acidification of intracellular compartments for normal endocytic and secretory functions. Recent experiments have begun to reveal how the kidney regulates these proton pumps independently. Vacuolar H+ ATPases are a family of structurally similar enzyme which differ in the composition of specific subunits. Cytosolic regulatory enzymes are present in renal cells which may affect vacuolar H+ ATPases in certain membrane compartments selectively. The vacuolar H+ ATPase in the plasma membrane of intercalated cells resides in a specialized proton-transporting apparatus that translocates the enzyme between an intracellular membrane pool and the plasma membrane in response to physiologic stimuli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00762528
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Traumatische Ruptur eines Nierentransplantats in eine chronische Lymphozele (1992)
    Springer
    Langenbeck's archives of surgery 377 (1992), S. 222-225 
    Details
    ISSN: 1435-2451
    Keywords: Lymphocele ; Kidney ; Transplantation ; Rupture ; Trauma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Lymphozelen sind eine seltene Komplikation nach Nierentransplantationen (in unserem Krankengut 2,2%) und treten typischerweise in den ersten 3–4 Monaten nach der Transplantation auf. Im späteren Verlauf sind sie eine Rarität. Die traumatische Ruptur eines Nierentransplantats ist in unserem Krankengut mit über 1200 Nierentransplantationen bisher einmalig. Es wird der Fall eines 28jährigen Marines geschildert, der 19 Jahre nach der Transplantation eine traumatische Nierentransplantatruptur erleidet. Durch das Trauma wird eine vorbestehende chronische Lymphozele klinisch manifest. Die Histologic der Lymphozelenwand zeigt Fett- und Bindegewebe mit ausgeprägter Fibrose. Das diagnostische und therapeutische Vorgehen wird beschrieben und mögliche Zusammenhänge den beiden seltenen Ereignisse diskutiert.
    Notes: Summary The lymphocele is a seldom complication after kidney transplantation (2.2% of our patients). This manifestation occurs typically 3–4 months after transplantation, as a late complication it's a rarity. The rupture of a kidney graft because of a trauma is unique in our clinical experience, which contains more than 1200 kidney transplantations. We report the case of a 28-year-old man who had 19 years after transplantation a traumatic rupture of the kidney graft. Because of the trauma a preexistent chronic lymphocele got clinically manifest. The histology of the lymphocele wall shows fatty and collagen tissue with a strong fibrosis. The diagnostic and therapeutic procedure is described. There are different possible relations between the rare problems: — the tight lymphocele carries over the force on the graft — the lymphocele has grown together with the graft at the lower pole and ruptures in this place — a little graft rupture makes a clinical manifest bleeding in the lymphocele because the deficiency of perirenal tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210277
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Cutaneous ion exchange, and renal and extrarenal partitioning of acid and ammonia excretion in the larval tiger salamander, Ambystoma tigrinum, following ingestion of ammonium salts (1992)
    Springer
    Journal of comparative physiology 162 (1992), S. 416-423 
    Details
    ISSN: 1432-136X
    Keywords: Acid-base balance ; Cutaneous ion exchange ; Kidney ; Ammonia ; Amphibian, Ambystoma tigrinum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The skin/gills and the kidneys of aquatic amphibians are potential sites of acid-base regulation. The roles of these organs in acid-base balance were examined in larval Ambystoma tigrinum following gastric infusion of ammonium salts. A single dose of 1.75 mEq NH4Cl·100 g-1 produced a mixed acidosis by 1 h after gavage. By 8 h after ingestion, pH and HCO 3 − had increased and PCO2 had decreased as the animals recovered. A prolonged acidosis was developed in a second group by gavage of an initial dose (1.5 mEq·100 g-1), followed by periodic maintenance doses (0.25 mEq·100 g-1) to prolong the disturbance for 8 h. The magnitude of the acidosis during this period was similar to that seen at 1 h after ingestion in the time-course study. A third group of larvae were given NaCl as a control for salt loading, which induced a small but significant respiratory acidosis. Unidirectional fluxes of Na+ and Cl- were examined during these serial ingestions. Salt loading inhibited the influx of the ingested ion. Na+ influx increased during the NH4Cl-induced acidosis. A fourth group of larvae were used to partition acid and ammonia excretion between the skin and the kidneys. These animals were given (NH4)2SO4 to allow re-examination of Cl- flux rates under non-Cl--loaded conditions. The ensuing acidosis had a reduced respiratory component and, therefore, pH did not decrease as much. Cl- influx rates did decrease significantly under these conditions. In both control and acidotic conditions, the majority of the acid efflux was as ammonia and the skin was the primary site of acid excretion. However, both the skin and the kidneys increased total acid excretion, although the efflux across the skin showed a much greater increase. This suggests a primary role for the skin in acid-base regulation in aquatic amphibians.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00258963
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Morphology of the kidney of the platypus (Ornithorhynchus anatinus: Monotremata) (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 234 (1992), S. 348-358 
    Details
    ISSN: 0003-276X
    Keywords: Morphology ; Kidney ; Urinary biology ; Ultrastructure ; Glomerulus ; Nephron ; Platypus ; Ornithorhynchus anatinus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The platypus kidney shows morphological similarities to those of other mammals. Macroscopically, the cortex is easily distinguishable from the fairly wide medulla. Within the medulla, no clear border is observed between the inner and outer zones. Light and transmission electron microscopically, the glomeruli show quite similar architecture to those of other mammals; however, the glomerular lobulation is very clear. The glomerular tufts are rather simple, but capillary lumen varies widely in size, which is one of the unique features of the platypus kidney. The urinary tubule is generally similar to that of human and other mammals in shape and segmentation; however, the staining specificities of histochemical reactions and the shape of epithelial cells of the Henle's loop differ from those ofother mammals. The most conspicuous features are: 1) although no protein casts are found in the tubular lumina, epithelial cells of the proximal convoluted tubule (PCT) have numerous electron-dense vesicles as in human nephrotic kidneys; and 2) the platypus Henle's loop consists of the thick epithelial cells similar to the mammalian type nephron of birds. As compared to those of other mammals such as humans and rats, our observations suggest that the platypus kidney is less developed, in terms of evolution.© Willey-Liss, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1092340306
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    O-versus S-protonation in diaryl sulfoxides: A semi-empirical mo investigation: Comparison with solution studies in superacids (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 244-252 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The protonation of diphenyl sulfoxide and several substituted diphenyl sulfoxides was probed by the MNDO-PM3 method to gain a theoretical insight into the experimentally observed preference for stable diphenyl sulfoxonium ion formation (O-protonation) in 1:1 FSO3H - SbF5 (Magic Acid) - SO2. In agreement with solution studies, O- protonation is uniformly favored (by ca 17 kcal mol -1) over S-protonation. The differences in the heats of formation of protonated and unprotonated diphenyl sulfoxides are increased by electron-withdrawing substituents (F, CF3) and decreased by electron-donating groups (Me, OMe). Variations in the SO bond length and bond order in the onium ions are compatible with simple resonance arguments and the oxonium/sulfonium character of both the O- and S-protonated onium ions. Surprisingly, the O- and S-protonated dibenzothiophene S-oxides are predicted to have identical energetics as compared with the corresponding protonated diphenyl sulfoxides. On structure optimization dibenzothiophene S-oxide itself, if the initial geometry is somewhat twisted, rearranges by ring expansion to give a new heterocycle with lower energy. A rotational barrier study on the parent O-protonated diphenyl sulfoxide showed two minima, separated by 1.3 kcal mol-1, at HOSC dihedral angles of 60° and 240°. The two conformations correspond to syn and anti orientations of the OH proton relative to the aromatic rings, and support the lowtemperature solution observations of the presence of two distinct sulfoxonium ions in solution. The rotational barriers for diphenyl sulfoxonium cation are compared with those of O-protonated dimethyl sulfoxide.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050505
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Theoretical studies on nitrile-forming elimination reactionsDetermination of Reactivity by MO Theory, Part 73. Part 72, 1. Lee, C. K. Kim, B. H. Kong and B. C. Lee, J. Phys. Org. Chem. 4, 449 (1991). (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 259-268 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The base-promoted nitrile-forming elimination reactions of YCH=CHCβH=NOCH=CHZ (Y=OCH3, H or Cl and Z=H or NO2) were studied by the AM1 MO theoretical method with Cl- as a base. The reaction is found to proceed by an E1cB-like E2 mechanism in which Cβ - H bond cleavage is more advanced than N - O bond breaking. The syn-elimination has a more E1cB-like transition state (TS) than the anti elimination, which is attributed to the structurally favourable nN - ó * (Cβ - H) charge-transfer interaction. An electron-withdrawing Y substituent lowers the activation barrier by stabilizing negative charge developed on Cβ in the TS. An electron-withdrawing substituent in the leaving group (Z = NO2) tends to enhance the anti relative to the syn elimination process by depressing the δ*(N - O) level, which in turn makes the nć - δ*(N - O) interaction more effective. The YCH=CH -  and  - CβH=N fragments are perpendicular in the TS, which is stabilized by delocalization of negative charge developed on the Cβ atom.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050507
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Stabilization of molecular association: An AM1/PM3 study of tetrahalomethane-arene molecular complexes (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 253-258 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An AM1/PM3 study of several tetrahalomethane-arene molecular complexes is presented. The results indicate the existence of weak attractive non-dispersion interactions in some of these complexes, which can be rationalized in terms of multipole - multipole and multipole - induced dipole interactions. No evidence was found for the occurrence of charge transfer in the ground states of these complexes.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050506
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050601
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Direct measurement of the energy barrier for 1,2-chlorine atom migration in α-methyl-α-chlorobenzyl(chloro)crbene (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 285-286 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The first direct determination of a 1,2-chlorine atom shift in a chlorobenzylcarbene was achieved by nanosecond laser flash photolysis. Arrhenius activation parameters of Eact = 3.39 ± 0.14 kcal mol-1 and log [A(s-1)] = 10.98 ± 0.14 were obtained for 1,2-chlorine migration in α-methyl-α-chlorobenzyl(ch1oro)carbene. The lifetime of this carbene is considerably longer than previously estimated and the measured Eact, is in excellent agreement with that determined by product analysis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050510
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Alkylation of pyridinium-N-phenoxide betaine dyes with iodomethane: Substituent, solvent and temperature dependence (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 275-284 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The rate constants of the pseudo-first-order methylation reaction of seven substituted pyridinium-N-phenoxide betaine dyes by iodomethane, were determined by UV-visible spectrophotometry in nine different solvents. The influence of substituents on the position of the long-wavelength, intramolecular charge-transfer absorption band of the unsubstituted betaine dye can be described by a modified Hammett equation. The solvent-dependent absorption constant ρA correlates satisfactorily with the acceptor properties of the nine solvents used. The substituent-dependent alkylation rate constants (In k) correlate linearly with the Hammett substituent constants, whereas the solventdependence of in k follows a more complicated pattern. Temperature-dependent measurements of the rate of alkylation exhibit an isoenthalpic behaviour for all the betaines in all the solvents investigated, i.e. the Arrhenius activation energy is almost constant for all differently substituted betaines in a given solvent. Temperature-dependent measurements of the alkylation rate of the unsubstituted betaine in different solvents led to an isosolvent relationship, i.e. the corresponding Arrhenius plots show a common point of intersection. According to the theory of isokinetic relationships, this isosolvent behaviour is interpreted in terms of a resonant energy exchange between the reacting species and the surrounding heat-bath system, which in this particular case seems to be the betaine molecule itself.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050509
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Quantitative aspects of chirality. I. Method of dissymmetry function (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 295-298 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: To study molecular features connected with chirality, a procedure for the quantitative estimation of the chirality level of compounds of different classes is needed. A procedure for estimating the molecular asymmetry level relative to mirror-reflection axes of symmetry, S1, S2, S4 and S6, has been developed. The geometrical mean of these parameters is the disymmetry function (DF). To calculate the DF, the molecule must be fixed in the coordinate system, transferred to the main axes of inertia.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050603
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Quantitative aspects of chirality. II. Analysis of dissymmetry function behaviour with different changes in the structure of the model systems (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 299-307 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The efficiency of the developed method of dissymmetry functions was studied using various model systems. The alteration of the dissymmetry function was analysed with systematic variations of the bond lengths, valence angles and masses of atoms in model tetrahedra. The behaviour of the dissymmetry function was studied for conformationally labile systems and chiral polyhedra. In general, it was found that in all cases the alteration of the dissymmetry function is in agreement with the speculative representations of the changes in degree of chirality.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050604
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Concerning the development of scales of solvent ionizing power based on solvolyses of benzylic substrates (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 287-294 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Based on analysis of recently reported measurements, it is suggested that, provided a sufficiently large set of specific rate measurements in a wide variety of solvent types is available, the negligible to moderate improvements in the correlations of other types of benzylic chlorides, which are gained by use of a benzylic chloride (in place of 1-adamantyl chloride) as the standard substrate, do not justify the development of new specialized scales of solvent ionizing power. A similar conclusion is reached concerning solvent ionizing power scales developed for use with benzylic p-nitrobenzoates. However, such scales could be helpful when specific rates of solvolysis in only a limited variety of solvents are available, e.g. when a change in mechanism severely limits the range of operation of one of the pathways. Contrary to a previous claim, variations in ion-pair return could be the cause of deviations from Grunwald-Winstein plots for solvolyses of benzhydryl chloride in fluorinated alcohol solvents; such effects could be coupled, at least in part, with variations in aromatic ring solvation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050602
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Charge-transfer transition energies and the prediction of reactivity in electrophile-nucleophile reactions (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 317-321 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The differences between charge-transfer transition energies calculated for donor-acceptor pairs at infinite separation and values determined experimentally for the charge-transfer complex geometry vary according to the charge type of the pairs and within a group of fixed charge type. It is argued that these differences provide a guide to the slope of the state-correlation curves for the product configuration in electrophile-nucleophile reactions of the corresponding charge type and that the observed variation invalidates the use of the simple expression ΔE=fΛ-β with constant f, derived from the curve-crossing model, to estimate energy barriers to reaction.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050606
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Quantitative aspects of chirality. III. Description of the influence of the structure of chiral compounds on their twisting power in the nematic mesophase by means of the dissymmetry function (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 308-316 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: For a number of chiral α,β-unsaturated carbonyl compounds, cyclohexanone and cyclohexenone derivatives, existing essentially in the form of single molecular conformation, the correlation dependences were established between the values of the calculated dissymmetry functions (DF) with respect to atomic masses and atom refractions, and the induction effectiveness of helical ordering in the nematic mesophase (twisting power). Such correlative dependencies, as the examples show, allow one to predict safely enough the twisting power of new substances with the ‘fixed’ molecular conformation. Types of dissymmetry functions and kinds of correlative dependences, the most acceptable for these reasons, were revealed. Dissymmetry functions formed on the basis of atom refractions (polarizabilities) describe the influence of the molecular structures of chiral compounds on the twisting power with higher accuracy than those that characterize the dissymmetry of the atomic masses distribution, according to the important role of the dispersion forces in the formation of helical ordering in liquid crystalline systems. The components characterizing the distribution dissymmetry of atomic refractions and masses with respect to the long and two shorter axes as the peculiar characteristics of biaxiality of chiral molecules describe the influence of the molecular structure on the twisting power with the same accuracy as the general DF do. Thus influence of chiral dopant molecules on the interactions between molecules in the uniaxial mesophases is negligible within the limits of the DF method. Based on the calculations for model systems it is established that the presence of the non-linear cinnamoyl fragment has a decisive influence on the molecular dissymmetry of the chiral α,β-unsaturated ketones. The alkyl groups influence the molecular dissymmetry only slightly, but it is important that their presence ensures the stabilization of the chiral conformer with the defined helicity of the cinnamoyl fragment.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050605
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Solvent and secondary substrate isotope effects on the acid-catalyzed ketonization of acetophenone enol in aqueous solution (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 322-326 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The enol of acetophenone was generated flash photolytically in aqueous solution by photosolvolysis of PhCBr=CH2 and photohydration of PhC≡CH and PhC≡CD, and rates of its ketonization were measured in dilute perchloric acid solutions in H2O and D2O at 25°C. The rate constants so obtained provide the solvent isotope effects, kH+/kD+ = 5.02 ± 0.08, and the secondary isotope effect for deuterium substitution at the β-position of the enol double bond, (kH/kD)β = 0.999 ± 0.014. Arguments are presented which show that these isotope effects requre a stepwise rather than a concerted mechanism for the ketonization reaction.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050607
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    New kinetic methods. 2.For Part 1 of this series, see Ref. 5. An indirect measurement of ester formation and hydrolysis rates (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 334-340 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The use of an assistant reagent to monitor spectroscopically the concentration of compounds that lack chromophores is described. It is demonstrated, for example, that the concentration of an aliphatic alcohol (present during acidcatalyzed hydrolysis or esterification reactions) can be monitored continuously by addition of a small amount of chromium trioxide. From a knowledge of the rate law and the rate constants for chromic acid oxidations, - d [CrO3]/dt = k [alcohol] [CrO3], the concentration of alcohol can be determined at any time by monitoring the absorbance of chromic acid at 363 nm. The rate at which the concentration of the alcohol is changing can then be used to calculate rate constants for the corresponding esterification or hydrolysis reactions. Rate constants obtained in this way are compared with those previously obtained by use of direct methods, and the application of this approach to the study of kinetics under conditions not accessible by other methods is illustrated.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050609
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Ionization constants of 5-furylmethylenehydantoins and 5-thienylmethylenehydantoins in 80% (w/w) dimethyl sulphoxide-water at 25°C (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 349-354 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The ionization constants of sixteen 5-furylmethylenehydantoins and 5-thienylmethylenehydantoins were measured in 80% (w/w) dimethyl sulphoxide-water solvent at 25°C. The effects of the 2-/3-furyl and 2-/-3-thienyl rings and the effects of configuration and conformation on acidity are discussed. The very low acidity of (Z)-5-(2-furyl)methylene-3-methylhydantoin suggests the possibility of some weak intramolecular interaction between the proton at N-1 and the 2-furyl oxygen in the s-cis conformation.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050611
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Reactions of molecules with two equivalent functional groups. 3. Nucleophilic substitution reactions of α, ω-dibromoalkanes [Br(CH2)nBr, n = 3,4,5] with potassium cyanide (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 327-333 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The substitution reactions of Br(CH2)nBr(1, n = 3-5) with KCN in methanol were studied in detail. Second-order rate constants k1 [formation of the mononitrile (2) from 1] and k2 (formation of the dinitrile (3) from 2) were determined, as were the rates for the reaction of H(CH2)nBr (4, n = 3-5) with KCN under the same conditions. The ratios k2/k1 ( = x) of the three homologs of 1 were found to be 1.15, 0.77 and 0.61 for n = 3, 4 and 5, respectively; a x value of 0.5 indicates that the functional groups behave independently. The second-order rate constants k1 (statistically corrected) and k2 exhibit modest enhancements compared with model compound 4 when any of the following substituents are present: δ or ∊-bromo, γ-, δ-, or ∊-cyano. By contrast, a γ-bromo substituent slightly retards the rate. These results indicate that the functional groups do influence each other to a modest degree by field effects which accelerate the reactions. Steric effects do not appear to play a significant role.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050608
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Catalysis in nucleophilic aromatic substitution reactions. A reinvestigation of the reaction between 1-fluoro-2,4-dinitrobenzene and n-butylamine (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 429-434 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The reaction between 1-fluoro-2,4-dinitrobenzene and n-butylamine in toluene shows a two-step plot of kobs, values vs the initial values of the concentration of the amine. The usual base-catalysis mechanism for HF elimination from the zwitterionic intermediate hardly explains this kinetic behaviour and the kinetic effect of addition of salts (and of 2-hydroxypyridine) to the reaction mixtures at different initial values of the concentration of n-butylamine. In contrast, the kinetic behaviours are easily explained by the presence of substrate-amine (or catalyst) interactions on the pathway of the substitution reaction.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050707
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Comparative study of aromaticity in five-membered rings containing S, SO and SO2 groups (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 74-82 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Owing to the importance of the concept of aromaticity, different indices have been developed to try to quantify this property. The possible π delocalization through an X—SOn—X group (X = C, N; n = 0, 1 or 2) could explain heteroaromaticity in rings containing the moiety. For that reason, the aromaticity of five-membered sulphurcontaining rings with different oxidation numbers (S, SO and SO2) and including no (thiophene), one (isothiazole) or two (1,2,5-thiadiazole) adjacent atoms was investigated. Ab initio calculations were carried out to determine geometrical parameters (planarity of the ring, bond length and bond order), electronic structure (charge distribution and dipolar moment) and the participation of d-orbitals of sulphur. According to these calculations, only compounds with S(II) can be considered to be aromatic, whereas compounds bearing S(IV) or S(VI) are better described as ylides.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Hydrolyses of terpenoid diphosphates. Effects of azide ion on products of hydrolysis (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 83-92 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hydrolysis of geranyl diphosphate (GPP) at pH 7 in water gives largely linalool (LOH) + geraniol (GOH) in the ratio of 3:1. Added N-3 generates mixed acylic allylic azides and increases the LOH GOH ratio to 15:1 in 2 M NaN3, but does not speed up the overall reaction. Hydrolysis of neryl diphosphate (NPP) gives largely α-terpineol (TOH) +p LOH, but their ratio is not very sensitive to NaN3 concentration although acyclic azide and small amounts of α-terpinyl azide (TN3) are formed. Hydrolysis of α-terpinyl diphosphate (TPP) gives large amounts of the cyclic alkenes, limonene and terpinolene. Added N-3 does not change the amount of elimination, but increases the ratio of limonene to terpinolene, and diverts some substitution product to TN3. Trapping of carbocationic species from GPP by N-3 is sharply increased by addition of Mn2+, which also catalyzes the overall reaction. Products of reaction of GPP are derived from acyclic intermediates and of NPP from acyclic and cyclic intermediates, and ionizations of the three substrates do not generate common carbocationic species.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050204
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Cyclopropylmethoxycarbene: A kinetic limit on the 1,2-carbon migration (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 104-107 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Cyclopropylmethoxycarbene undergoes ambiphilic-nucleophilic intermolecular reaction with alkenes and methanol, but its intramolecular chemistry (1,2-carbon migration) is suppressed (k 〈 3 × 103 s-1) by the α-methoxy substituent.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050301
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Chemiexcitation of an anthraquinone derivative in the thermal cycloreversion of a dewar-anthraquinone derivative (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 101-103 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dewar-anthraquinone (1a) and 1,2,3-tri-tert-butyl-5,8-Dewar-anthraquinone (1b) were synthesized. Thermodynamic parameters for their cycloreversion to the corresponding anthraquinones indicate that thermal population of the excited states of the products via non-adiabatic valence isomerization is energetically feasible. On thermolysis of 1b, the formation of a detectable amount of 1,2,3-tri-tert-butyl-1,4-Dewar-anthraquinone (3) was observed. The excited singlet state of 1,2,3-tri-tert-butylanthraquinone (2b) produced via the non-adiabatic process is responsible for the formation of 3.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050206
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Molecular modelling of organophosphorus podands and their complexes with alkali metal cations (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 109-118 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A molecular mechanics study on some organophosphorus podands, with both rigid and flexible terminal groups, and on their complexes with Li+ and Na+ was carried out. Na+ causes smaller deformations of the ligands than Li+, but its complexes are less stable, as the interaction energy with the podands is weaker. The ligands with rigid terminal groups are, in general, more pre-organized for complex formation. The cation-ligand interaction energies, including also the changes in steric energies, are always higher in complexes of flexible molecules than in those containing rigid ligands. The lower entropy losses which accompany the formation of complexes of rigid molecules with alkali metal cations probably account for the observed higher stabilities of the complexes.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050302
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Hammett reaction constants for irreversible electroreduction of iodobenzenes in non-aqueous solvents (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 119-122 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polarographic half-wave potentials for the electrochemical reduction of a series of para-substituted iodobenzenes in acetonitrile, acetone, benzonitrile, dimethylformamide, dimethyl sulphoxide and methanol obey Hammett equations and the reaction constant found, ρ = 0·36 ± 0·02, is independent of the solvent used. The results obtained are discussed on the basis of a mechanism of the electrode process.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050303
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Enthalpies of solution and intermolecular forces. tert-butyl halides in hydroxylic solvents (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 93-100 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The application of cavity theories of solution and linear solvation energy relationships to the interpretation of enthalpy of solution values of tert-butyl halides in hydroxylic media, measured at 25 °C and infinite dilution, is deserted, in order to define the intermolecular forces acting between solutes and solvents. It is concluded that solvent dipolarity and solvent HBD acidity effects dominate the solution process. An empirical equation relating the enthalpies of solution with selected properties of both solvents and solutes is proposed. New experimental Δ Hs∞ values for tert-butyl iodide in 13 alcohols are reported.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050205
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Laser flash photolysis study of 10, 10-dimethyl-9-anthrylidene, a carbene with nearly degenerate singlet and triplet states (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 123-128 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 10, 10-Dimethyl-9-anthrylidene (DMA) was studied by laser flash photolysis (LFP) techniques. LFP of the requisite diazo precursor in pentane or carbon tetrachioride produced transient spectra attributed to the hydrocarbon and monochlorinated diarylmethyl radicals, respectively. In the presence of pyridine and oxygen, ylides were formed upon LFP of 10, 10-dimethyl-9-diazoanthrone. However, ylides are not formed in acetonifrile or acetone. The carbene itself was not detected by transient absorption spectroscopy. The absolute rate constants for reaction of DMA with pyridine, methanol and triethylsilane are 1·96 × 109, 1·8 × 1010, and 1·0 × 108 I mol-1 s-1, respectively. It is concluded that the singlet and triplet states of DMA are essentially degenerate.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050304
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Transimination reaction between pyridoxal-5′-phosphate schiff bases with dodecylamine and amino acids (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 142-154 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Some transimination processes were studied using an intermolecular model formed by pyridoxal-5′ -phosphate (PLP) an amino acid and dodecylamine (DOD) in an aqueous medium. All the kinetic constants for the reversible reaction were determined. The results show that in these cases transimination proceeds through an addition-elimination by forming a diamine geminal intermediate. Equilibria are always shifted to dodecylamine-PLP Schiff base formation. Differences between the stability of this Schiff base and the ∊-aminocaproic Schiff base cannot be explained only on the basis of the different nucleophicities of amine groups and therefore differences in the imine double bond environment must be taken into account to explain this behaviour.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050306
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Cycloaddition of heterofunctionalized allenes with tert-butylthioacrylonitrile. Determination of activation parameters for diradical intermediate formation and the detection of reversible ring closure (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 160-170 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The cycloaddition reactions of 4-methylphenylthio-, methoxy-, 4-methoxyphenyl-, phenyl-, chloro- and cyanoallene with tert-butylthioacrylonitrile (BTA) in toluene-d8 solution were investigated. The relative reactivity sequence of these substituted allenes is 4-methylphenylthio ∼ methoxy- 〉 4-methoxyphenyl- 〉 phenyl- 〉 chloro- 〉 cyanoallene. Activation parameters were measured for diradical intermediate formation of BTA with 4-methylphenylthio-, methoxy- and 4-methoxyphenylallene, giving average values of Ea and ΔS± of 14.2-16.8 kcal mol-1 and ca. -33 eu, respectively. The relative reactivity sequence is consistent with a FMO allene-HOMO, BTA-LUMO dominant interaction for diradical intermediate formation. However, the regioselectivity of attack on the substituted allene appears to be thermodynamically controlled. The formation of the diradical intermediates in these cycloaddition processes appears to be irreversible. However, the ring closure of the diradical intermediates formed from 4-methylphenylthio-, methoxy- and 4-methoxyphenylallene is reversible under the conditions of the kinetic experiments. The kinetically controlled ring closure of the diradical intermediates is allyl radical SOMO controlled, while the final cycloadduct distribution is thermodynamically controlled.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050308
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050401
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Protonated propylene oxide is stable towards isomerization in the gas phase (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 201-208 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The relative stabilities of gaseous protonated propylene oxide and its isomers, protonated propanal, oxetane and acetone, were reinvestigated in a Fourier transform ion cyclotron resonance mass spectrometer by using multiple-stage tandem mass spectrometri experiments. The dependence of ion structure on internal energy was examined by generating the ions in proton transfer reactions with different exothermicities and then probing their structures by using energy-resolved mass spectrometry (collision-activated dissociation as a function of collision energy). In contrast to results obtained in several recent investigations, protonated propylene oxide was found to be distinct from its more stable isomers when generated with only a small amount of internal energy. When the exothermicity of the proton transfer reaction was higher than 6 kcal mol-1 (1 kcal = 4·184 kJ) or when the epoxide ion was subjected to multiple activating collisions, rapid isomerization to protonated propanal occurred. The energy required for opening of the epoxide ring estimated to be similar to that measured earlier for protonated cyclohexene oxide (5-10 kcal mol-1).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050405
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    ESR study of solvent effects on the electronic structure of 2-(4′ -dialkylaminophenyl)indan-1,3-dionyl radicals (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 218-224 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The ESR spectra of 2-arylindan-1,3-dionyl radicals in various solvents at 343 K were obtained and assignments of the hyperfine structures were made. The hyperfine coupling constant (hfcc) of the dimethylamino nitrogen increases whereas the 2',6'-hydrogen hfcc decreases as the ET value, a solvent polarity parameter, increases. MO calculations were made according to the semi-empirical procedure of Rieger and Fraenkel; the nitrogen and oxygen Coulomb integrals were adjusted so that the calculated spin density on the nitrogen atom agrees with that estimated from its hfcc. It is found that the π-moment of the radicals increases from 9·13 D in toluene to 9·85 D in acetic acid. The solvent dependence of the equilibrium between the radicals and its dimer has been explained in terms of the solventinduced π-moment in polar solvents.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050407
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Heats of formation of organic molecules by ab initio calculations. Aldehydes and ketones (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 225-229 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A bond and group equivalent scheme that allows the calculation of heats of formation for aldehydes and ketones from ab initio 6-31G* energies has been developed. For a group of 24 aldehydes and ketones, the RMS error for the calculated heat of formation was 0 · 46 kcal mol-1. Heats of formation have been predicted for an additional seven compounds for which the experimental values are believed to be either in error or unknown. There are some problems with the norbornanones.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050502
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Substituent effect on the relative strength of some arylthiomethyl- and arylsulphonylmethylbenzoic acids (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 239-243 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The pK values of some arylthiomethylbenzoic acids and the corresponding sulphones were determined spectrophotometerically. The role of substituent and the position of the carboxylic group are discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050504
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Experimental and theoretical study of the influence of the solvent on asymmetric diels - alder reactions (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 230-238 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Rate, endo/exo and diastereofacial selectivities of the Diels-Alder reaction between cyclopentadiene and ( - )-menthyl acrylate were measured in a series of organic solvents and organic-aqueous mixtures. Regression analyses show that a model with the α empirical solvent parameter accounts for most of the changes in rates and diastereofacial selectivities, whereas in the case of the endo/exo selectivity, inclusion of the π* and δ parameters is needed. Theoretical calculations carried out on the model reaction between methyl acrylate and cyclopentadiene using dielectric continuum and supermolecule models do not clearly show the effect of the different solvation mechanisms on rate. However, they agree with the above-mentioned influence of α and π* on the endo/exo and diastereofacial selectivities.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050503
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Enhancement or suppression of CIDNP intensities by a second magnetic nucleus: Interplay between g factor difference, external magnetic field, and hyperfine coupling constants (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 209-217 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The enhancement factors of the 1H polarization induced in radical pairs generated by α-cleavage of 12C=O- and C=O-labelled ketones deviate from the ratios expected on the basis of the relative abundances of the respective carbon isotopomers. For dibenzyl ketone, the ratio of absolute CIDNP intensities of the 1H(13C) doublet (90% 13C=O) to the 1H(12C) singlet (10% 12C=O) was found to be 〉9:1 at 58·3 kG and 〈9:1 at 21 kG. Similar deviations were observed for other 13C labelled ketones, viz. deoxybenzoin (13C=O) and acetophenone (13C=O or 13CH3). This novel enhancement or suppression effect on the CIDNP enhancement can be ascribed to the presence of a second hyperfine coupled nucleus in the intermediate radical pair. The individual contributions of the g factor difference (Δg), the external magnetic field strength (Ho), and the hfc constants of the observed (aA) and the interacting nucleus (ax) in the enhancement-suppression are exemplified. The experimental results are consistent with theoretical calculations of the mutual effect of Δg, H0, aA and ax on the CIDNP enhancement factor of the observed nucleus.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050406
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Reduction of 1-benzyl-3-cyanoquinolinium ion by phosphonate: Solvent effects in propan-2-ol-water mixed solvents (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 269-274 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Rate constants (k2) were determined for the reduction of 1-benzyl-3-cyanoquinolinium ion by phosphonate dianion in mixed solvents consisting of propan-2-ol and water. The reduction product was mostly 1-benzyl-3-cyano-1,4-dihydroquinoline with a trace of the 1,2-isomer. The solvent properties were varied by increasing the fraction of water in the mixed solvent, which increases the polarity of the solvent. Increasing the proportion of alcohol makes the solvent a better electron pair donor. The higher fraction of propan-2-ol in the mixed solvent gives rise to a substantial increase in k2. A quantitative comparison of the solvent effect on this reaction with the solvent effects on related reactions suggests a solvent Brønsted α value of 0·45. This suggests that the PO3- unit of the transition state interacts only weakly with the solvent although the final oxidized product is phosphate.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050508
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Interaction of formamide with stilbazolium betaines: Steric effects in amides (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 609-613 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The visible spectrum of di-tert-butylstilbazolium betaine (DTBSB) was recorded in eight simple amides. The appearance of a ‘coarse’ structure in the main absorption band is due to the shielding effect of the tert-butyl groups, which hinder the approach of the solvent. Since this structure disappears in formamide, it is concluded that this solvent associates through its NH to the carbonyl group of DTBSB. For the other amides, there is a clear relationship between the steric effect, for both the N- and C-substituents, of the solvent-solute hydrogen bond association and the structure of the visible band.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050909
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Structure of, and internal rotation in, hexakis [4-(2-phenylpropan-2-yl) phenoxy] benzene, and structural comparison with its precursor phenol 4-(2-phenylpropan-2-yl)Phenol (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 628-632 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The title compounds (1 and 3, respectively) were studied by X-ray crystal structure analysis. Both are trigonal, space group R3, with lattice parameters a = 27.718(6), c = 8.161(2) Å, Z = 3 and a = 31.267(7), c = 6.560(2), Z = 18, respectively. The dodecamethyl compound 1 is isomorphous with its parent hexakis(4-benzylphenoxy)benzene (2), a known host. However, ‘collapse’ along the c-axial direction has occurred such that the appreciable clathrate cavity of 2 has been replaced by only a very small residual void for 1. Phenol 3 does not pack in discrete [OH]6 hydrogenbonded hexamers; instead, molecules are assembled in infinite chains, linked by OH…O hydrogen bonds of length 2.735(3) Å, which are propagated along threefold screw axes. A variable-temperature CPMAS NMR study of sidechain aryl group rotation in 1 gives a value ΔG≠ of 14.0 ± 0.7 kcal mol-1 (at 42 °C) for the (crystallographically unique) para -disubstituted ring, a similar 14 kcal mol-1 free energy barrier being found hindering rotation of this ring, and of the outer phenyl ring of 1, at 9°C.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610051003
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Diastereofacial selectivity in 1,3-dipolar cycloadditions to cyclobutens. 8. HF/3-21G transition structures of the reactions of formonitrile oxide with CIS-3,4-dichlorocyclobutene and norbornene (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 819-823 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A transition structure for the syn and anti attack of formonitrile oxide on both cis-3,4-dichlorocyclobutene and norbornene was obtained using HF/3-21G method. These calculations correctly predict dominance of the syn attack in the reaction of dichlorocyclobutene and 100% syn selectivity, with respect to the methano bridge, in the reaction of norbornene. Analysis of the activation energy shows that the inherent facial bias of dichlorocyclobutene is reflected, at the transition state, in a complex way in the deformation energy of both dichlorocyclobutene and formonitrile oxide and in the interaction energy between them. With norbornene the out-of-plane deformation energy of the olefinic hydrogens clearly emerges as the major factor in controlling facial selectivity.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610051207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610051001
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Effect of hexadecyltrimethylammonium bromide micelles on the rate of oximolysis of esters (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 341-348 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two amphiphilic oximes, 10-phenyl-10-hydroxyiminodecanoic acid (oxime II) and 4-(9-carboxynonanyl)-1-(9-carboxy-1-hydroxyimino nonanyl)benzene (oxime III) were synthesized. The pKa values of oximes II and III and acetophenoxime (oxime I) and the rates of oximolysis of p-nitrophenyl acetate (NPA) and p-nitrophenyl octanoate (NPO) were determined in the presence and absence of micellar hexadecyltrimethylammonium bromide (CTAB). The rates of oximolysis increased by up to 3 × 104-fold in the presence of CTAB. Quantitative analysis of micellar effects, using an ion-exchange pseudo-phase model, allowed the determination of the second-order rate constants for the reactions of oximes I-III with NPA and NPO in the micellar pseudo-phase. The calculated rate constants in the micellar pseudo-phase were lower than those in water, demonstrating that the rate enhancements were due to substrate concentration in the micelles. Comparison of the rate constants in micelles and water suggests that the sites of reaction of oximes I-III with NPO and NPA are similar to those in bulk aqueous solution. Micellar incorporation of the hydrophobic oximes II and III does not lead to a major change in the nucleophilicity of the oximate anion.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050610
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Photochemical reactions of 2,2′-furil. Solvent dependent photoreduction via the lowest excited singlet and triplet states (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 355-360 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 2,2′-Furil (di-2-furyl diketone) undergoes photoreduction to give furoin on irradiation at 366 nm in triethylamine-containing benzene and ethers. On the other hand, in ethanol the photoirradiation leads to the formation of an enediol type of compound, 1,2-di(2-furan)ethene-1,2-diol. The results of quenching and sensitization both for the photoreactions and the phosphorescence demonstrate that furoin and the enediol are formed via the lowest excited singlet and the triplet states of 2,2′-furil, respectively.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050612
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050701
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Quantum mechanical and molecular mechanical studies of the hydrolysis of methyl nitrate and the solvent effect (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 361-366 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The alkaline hydrolysis reaction of methyl nitrate was simulated by quantum mechanical and molecular mechanical methods. The gas-phase reaction was calculated to proceed with no barrier when ab initio calculations at the STO-3G level were utilized, and with a very small barrier (5.70 kJ mol-1) when the MINDO/3 method was applied. In solution, the solvation energy was estimated to be 70.33 kJ mol-1 by molecular mechanical calculations. Thus the activation energy (76.03 kJ mol-1) of alkaline hydrolysis of methyl nitrate was found to be in good agreement with the available experimental value (82.42 kJ mol-1). The results indicated that the substantial activation barrier in alkaline hydrolysis was essentially solvent-induced.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050613
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Solvolysis of 1,1-diphenylethyl derivatives in highly aqueous media. Reaction via ion pairsPaper presented in part at the Third European Symposium on Organic Reactivity (ESOR III), Goteborg, Sweden, 1991. (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 367-371 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Solvolysis of 1,1-diphenyl-1-X-ethane (1-X) [X = 4-nitrobenzoate (PNB), 3,5-dinitrobenzoate (DNB), AcO, MeOH+, EtOH+ or H2O+] was studied in 20 vol% dimethyl sulphoxide in water, in which specific salt effects are very small, and in 25 vol% acetonitrile in water. Substrates with negatively charged leaving groups yield more elimination product 1,1-diphenylethene (3) than those with uncharged groups, indicating the intermedicacy of ion pairs. Thus, three times more alkene is formed in the reactions of the substrates 1-OAc and 1-PNB than in the acid-catalysed hydrolysis of 1-OMe and 1-OAc. The substitution products may be formed via the solvent-equilibrated carbocation since the measured nucleophilic selectivities are very similar with different leaving groups.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050614
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Oxidation of indole by N-sodio-N-chlorobenzenesulphonamide (chloramine-B) in alkaline medium catalysed by os(viii): A kinetic and mechanistic study (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 373-381 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of oxidation of indole (In) and 5-substituted indoles (OCH3, Br and Cl) by chloramine-B (CAB) were studied in alkaline medium with Os(VIII) as catalyst at 303 K. At low [In]0 the rate law rate = k [CAB] [Os(VIII)] [In]0 is obeyed, which changes to rate = k [CAB] [Os(VIII)] [OH-]-1 at higher substrate concentrations. Variation of ionic strength has no effect on the rate and the dielectric effect is negative. The reaction was studied at different temperatures and activation parameters were evaluated. Hammett correlation of substituent effects indicated a linear free energy relationship with ρ+ = - 1.0, showing the formation of an electrondeficient transition state. From enthalpy-entropy relationships and Exner correlations, the isokinetic temperature β was found to be 330 K, indicating enthalpy as a controlling factor. The mechanism assumes the formation of a complex between oxidant and Os(VIII) at high and low [In]0. Proton inventory studies in H2O-D2O mixtures showed the involvement of a single exchangeable proton of OH- ion in the transition state.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050702
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Molecular mechanics of bridged ferrocene derivatives: Conformational energy surfaces of [3]-, [4]- and [45] ferrocenophanes (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 382-394 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A molecular mechanical model is presented which allows computational interpretation of stereodynamics in ferrocenophanes by using a simple form of bending potential for angles involving the central iron atom and extended to carbon atoms of different cyclopentadienyl rings. Potential energy surfaces of [3] -, [4] - and [45] ferrocenophanes were studied in detail. For [3] ferrocenophane, the calculated energy barrier of the bridge reversal process agrees well with the experimental value. The previous interpretation of a rigid bridge in [4] ferrocenophane is questioned on the basis of the calculated low barriers. The predominance of experimentally indistinguishable enantiomeric pairs may be responsible for the misinterpretation. [45] Ferrocenophane is estimated to interconvert into D5-symmetric global energy minima over barriers of 13-15 kcal mol-1 through one-by-one flipping of five tetramethylene bridges.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050703
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Using theoretical descriptors in quantitative structure activity relationships: Some physicochemical properties (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 395-408 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The application of computational techniques to biology, chemistry and physics is growing rapidly. Quantitative structure-activity relationships (QSAR) have been used widely to relate biological activities and physicochemical properties to molecular structural features. A difficulty in this approach has been non-uniformity of parameter sets resulting in the inability to examine contributions across properties and data sets. Linear solvation energy relationships (LSER) developed by Kamlet and Taft successfully utilize a single set of parameters to correlate a wide range of biological, chemical and physical properties. The empirical LSER solvatochromic parameters have been replaced with theoretically determined parameters to permit greater ease in a priori property prediction. These TLSER descriptors have given good correlations and interpretations for some biological activities. This paper discusses the application of these descriptors to six physicochemical properties involving equilibria, kinetics and spectra. The results show good correlation and physical interpretation.
    Additional Material: 12 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050704
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    O-17 NMR studies on α-diazoketones (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 424-428 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The O-17 NMR spectra of 13 α′-alkyl- and aryl-substituted α-diazoketones were measured. The results obtained show a clear discrimination between them. A good correlation in a series of para-substituted α-diazoacetophenones between O-17 chemical shifts and both α+p and dual substituent parameters indicated a greater contribution of resonance than inductive effects.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050706
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Kinetics of deprotonation of triphenyl(2-substituted-9-fluorenyl)phosphonium ions in 50% dimethyl sulfoxide-50% water. Intrinsic rate constants, imbalances and evidence for changes in transition state structure (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 409-423 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Rate constants (kB1 and kBH-1) for the reversible deprotonation of triphenyl(2-Z-9-fluorenyl)phosphonium ions (Z = H, Br, NO2) by piperidine, morpholine, n-butylamine, 2-methoxyethylamine, glycine ethyl ester, cyanomethylamine, OH- and water were determined in 50% Me2SO-50% (v/v) water at 20°C. Brønsted αCH (variation of carbon acid) and β values (variation of amine), and intrinsic rate constants [log k0 = log kB1/q when pKBHa - pKCHa + log(p/q) = 0] were obtained. αCH decreases with increasing basicity of the amine whereas βB decreases with increasing acidity of the carbon acid. These trends, which imply changes in the transition-state structure with reactivity, can be described by the interaction coefficient pxy = ∂βB/∂pKCHa = ∂αCH/ - ∂pKBHa = 0.03 (primary amines) and 0.01 (piperidine/morpholine). αCH is smaller than βB, indicating an imbalance due to a lag in the delocalization of the negative charge into the fluorenyl moiety at the transition state. The influence of the Ph3P+ group on the intrinsic rate constant is analyzed in terms of possible contributions by inductive/field (I), resonance (R), polarizability (P) and steric (S) effects. Using 9-carbomethoxyfluorene as a reference, it is shown that the stronger electron-withdrawing I effect of the Ph3P+ group relative to the COOMe group enhances log k0 substantially; the fact that the R effect of Ph3P+ is weaker than that of COOMe also contributes to an increase in k0, and so does the P effect of the phosphorus. All these increases are virtually completely offset by the rate-retarding S effect of the bulky Ph3P+ group. A similar analysis for the Me2S+ derivative studied by Murray and Jencks [J. Am. Chem. Soc. 112, 1880 (1990)] leads to similar conclusions except that the still smaller R effect is probably one of the main reasons why k0 for the Me2S+ derivative is more than ten times higher than for the Ph3P+ derivative; another potential reason is a difference in the steric effect.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050705
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050801
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Editorial (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 435-435 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050802
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Complexes of TRI- and tetraprotonated forms of 1,4,7,10,13-pentaazacyclopentadecane with various mono- and divalent anions in aqueous media (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 443-450 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acid dissociation and anion complexation properties of 3+ and 4+ forms of 1,4,7,10,13-pentaazacyclopentadecane were investigated by pH potentiometry, conductometric titration and 13C NMR experiments. The 3+ and 4+ species form complexes with a variety of mono- and divalent anions, and their complexation constants can be determined by pH potentiometric methods. However, no iodide complexes are detected and neither is a pentaprotonated species. Enthalpy and entropy changes for the acid dissociation of the 3+ ligand and for its complexation with chloride are estimated. The complexation and acid dissociation properties of the ligand are discussed in terms of internal hydrogen bonding interactions and solvation effects.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050804
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Potentiometric evaluation of the ion-selective characteristics of 2-borono-1,3-XYLYL crown ethers (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 437-442 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(vinyl chloride) (PVC) membranes impregnated with 2-borono-1,3-xylyl crown ethers were evaluated in ion-selective electrodes. The response pattern obtained with these crown ethers appears to be essentially independent of ring size but there is a linear correlation between selectivity and hydration enthalpy of the cation which is similar to that obtained for electrodes prepared only with the lipophilic anionic site KTCIPB. The similarities in correlation and mechanism between these two types of electrodes has been attributed to the presence of anionic sites in both cases dominating the observed selectivity. For the four ionophores considered the pH-dependent ionization of the boronate group to the boronate anion is proposed to be responsible for the domination of anionic sites on the properties of the ionophores. The ionophores proved to be good K+ neutral carriers, showing responses to this ion in the range 10-1-10-4 M. The compounds tested showed a fast response to changes in K+ concentration which was stable to within 〈 0.2 mV h-1.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050803
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Alkali metal ion-assisted cleavage of crown ether anisoles by toluenethiolate anion (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 457-460 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of alkali metal ions (Li+, Na+, K+, Cs+) on the reactivity of toluenethiolate anion in the demethylation of 2-methoxy-1,3-xylyl-18-crown-5, 2-methoxy-1,3-xylyl-24-crown-7 and the model compounds anisole and 2,6-dimethylanisole was investigated in dimethylformamide (+3.3 M water) at 60°C. It was found that the metal ion effects are markedly influenced by the presence of the polyether chain in the reaction system. Whereas reactions of the model compounds are slightly inhibited by the presence of alkali metal ions, the latter strongly enhance rate of demethylation of the crown ether derivatives, the observed catalytic factors ranging over nearly three orders of magnitude. These remarkable rate-enhancing effects are ascribed to a strong transition-state stabilization by metal ions through cooperation of electrostatic binding with the negative charge developing on the oxygen atom of the methoxy group undergoing nucleophilic attack and coordinative interaction with the polyether chain.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050806
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Effect of counterion binding and alkyl chain length on the phase transition behaviour of DI-n-alkyl phosphate vesicles (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 451-456 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This paper describes a fluorescence depolarization and 31P NMR spectroscopic study of the phase transition behaviour of a series of identical and mixed-chain di-n-alkyl phosphate vesicles in the presence of different counterions (Na+,K+,Me4N+,Ca2+). Using trans, trans, trans-1, 6-diphenyl-1, 3, 5-hexatriene (DPH) as a fluorescent probe, the fluorescence polarization (P) was measured for the identical-chain vesicles (Na+, K+, Me4N+) as a function of temperature. The temperature for the main phase transition (Tm) only responded to variation of the counterion in the case of the longer-chain di-n-alkyl phosphates, with Tm decreasing in the sequence Na+ 〉 K+ 〉 Me4N+. This result is rationalized in terms of a decreasing counterion binding, which affects chain ordening in the core of the bilayer. Peak intensities and line widths of the 31P NMR resonances for the bilayer vesicles suggest a more complex phase behaviour, but the overall results are reconcilable with the picture emerging from the fluorescence depolarization experiments. Fluorescence depolarization measurements were also carried out with vesicles formed from the sodium di-n-alkyl phosphates and in the presence of various concentrations of Ca2+ (0-6 mM) at temperatures above Tm. For both the identical-chain and mixed-chain di-n-alkyl phosphate vesicles, a steep increase in P was found between ca 1.0 and 1.4 mM Ca2+, indicative of a strong Ca2+-induced ordening of the alkyl chains.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050805
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Survey of the DNA binding properties of natural and synthetic polyamino compounds (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 461-466 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Using a flourescence-detected ethidium displacement assay, the calf thymus DNA complexation properties of 27 mono-, di-, tri-, tetra- and hexacationic polyamines were determined. The DNA-binding affinity of these polyamine compounds increased with increasing cationic charge on the polyamine. Although most of the compounds exhibited no base pair binding selectivity, two of the tricationic polyamines possessing additional neutral amine groups exhibited approximately tenfold GC binding selectivities.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050807
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Modulation of the cation complexing properties in the ‘lower rim’ chemically modified calixarene series (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 496-501 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of chemical modifications on the lower rim of calix [n] arenes is analysed with respect to the cation binding ability of the receptor. Extraction data and stability constants of the complexes are discussed. Three main factors are investigated: the size of the calixarene, the conformation of the calixarene and the nature of the ligating group attached to the phenolic oxygen. The work concentrates on esters, ketones, amides, thioamides and carboxylic acids. Some data concern chemically modified tetrahomodioxacalix [4] arene esters.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050811
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Binding cooperativity in the self-assembly of double stranded silver(I) trihelicates (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 529-532 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Spectroscopic and potentiometric studies of Ag(I) binding by tris-bipyridine strands indicate that the formation of trinuclear silver trihelicates is a process displaying positive cooperativity.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050815
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Supramolecular control of molecular electronic behaviour of TCNQ-. salts (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 533-539 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Crown ether complexation of 1:1 alkali metal TCNQ salts, MTCNQ (M=K, Rb, Tl) leads to structures containing isolated TCNQ dimers. These materials provide valuable models for investigating the spectroscopic and electronic behaviour of TCNQ-. dimer components which are key structural fragments of, for example, organic metals and semiconductors.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050816
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050901
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Partial rate factors in photochemistry: The meta photocycloaddition of methylbenzenes to cyclopentene (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 581-589 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The partial rate factors of the four modes of meta photocycloaddition of methyl-substituted benzenes to cyclopentene have been determined by measuring quantum yields of formation of the most important meta photocycloadducts of benzene, toluene and the three xylenes. It is demonstrated that the results can be applied to predict quantum yields of any meta photocycloadduct of methylbenzenes to cyclopentene. The predicted yields agree very well with those determined experimentally, and it is shown that the effects of two or more methyl groups are fully additive. The method is promising for the investigation of mechanisms of photochemical reactions and can be used to predict regioselectivities.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050905
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Ionization kinetics of rhodamine b leucocyanide in the presence of poly(vinylbenzyltrimethylammonium chloride) (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 595-599 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The participation of the carboxylate group in the ionization of Rhodamine B leucocyanide was studied in an aqueous solution of poly(vinylbenzyltrimethylammonium chloride) (PVBTA) or cetyltrimethylammonium bromide (CTAB) at constant temperature and pH 8. The experimental rate constant (kexp) decreases with increasing PVBTA concentration. The results are interpreted in terms of the binding of the ionized form of Rhodamine B leucocyanide (RBCN-) to a single class of completely independent binding sites on the PVBTA. From this model, a value of 1.09 × 106 l mol-1 was obtained for the binding constant. The effect of CTAB is different from that obtained with PVBTA. After a region in which there are large changes in kexp with the CTAB concentration, this constant reaches a zone where its value is independent of the surfactant concentration. The decrease in kexp in the first zone was explained in terms of an ionic association between RBCN- and the cationic heads. In the second zone, it was assumed that a micellar effect operates on the ionization kinetics. In a similar form, the esterification of the carboxylate group leads to a slower ionization rate.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050907
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Dynamic behaviour of [2] metacyclo [2] (3,4) thiophenophane (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 617-618 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The conformational analysis of dimethyl [2] metacyclo [2] (3,4)thiophenophane (1), which is the thiophene analogue of [2.2] orthometacyclophane, is described. The comparison between the dynamic NMR spectra of 1 and the computer-simulated spectra led to the energy barrier between syn and anti conformers of 1. This is the first conformational analysis of a [2,2] orthometa-type cyclophane.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610050911
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Supramolecular metallocatalysts for the cleavage of amino acid esters (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 619-627 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Transition metal ions are effective catalysts of the hydrolytic cleavage of amino acid esters and their effects can be enhanced and properly directed when they are chelated to functionalized ligands. The resulting metallocatalysts are attracting increasing attention and the systems so far investigated are briefly reviewed. Particular emphasis is given to supramolecular systems which may add to the metallocatalysts the benefits of the cooperativity, set upon convergent non-covalent interactions of their components, needed for substrate recognition. The results obtained with metallomicellar aggregates and molecular metalloreceptors, with particular reference to those studied in the authors' laboratory, are reported in more detail. In the case of loosely structured metallomicelles, remarkable accelerations and, generally, modest selectivities have been observed; less spectacular kinetic effects, but promising substrate selectivity, have been obtained with structurally well defined metalloreceptors.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610051002
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    The photochemistry of pyrene-cytosine conjugates: Modelling the carcinogenic action of aromatic hydrocarbons (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 644-648 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Photoreduction, but not the corresponding photooxidation, of cytosine can be sensitized by a covalently appended pyrene molecule in a process that may have some importance for understanding the known carcinogenic activity of polynuclear aromatic hydrocarbons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610051005
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Molecular recognition by macrocyclic receptors having multiple hydrophobic branches in a synthetic bilayer membrane (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 633-643 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Hybrid molecular assemblies were prepared in combinations of a synthetic peptide lipid, involving an L-alanine residue interposed between an anionic head group and a hydrophobic double-chain segment, with cationic macrocyclic hosts, a steroid cyclophane bearing four rigid steroid moieties and octopus cyclophanes having eight flexible hydrocarbon branches. On addition of the cyclophanes to multi-walled bilayer membranes composed of the anionic lipid, thermodynamic parameters (ΔH and ΔS) associated with the phase transition between the gel and liquidcrystalline states were subjected to changes that are consistent with the formation of the hybrid assemblies. Anionic fluorescent guests, 8-anilinonaphthalene-1-sulphonate and 6-p-toluidinonaphthalene-2-sulphonate, were effectively incorporated into the hydrophobic cavities provided by the cationic cyclophanes embedded in the bilayer membrane through hydrophobic and electrostatic interactions. The guest-binding modes of the hybrid assemblies are classified into two types; a guest is included in the proximity of the hydrogen-belt domain of the bilayer membrane in one mode, and a guest is incorporated into the hydrophobic bilayer domain composed of double hydrocarbon chains of the lipid in another.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610051004
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Alkaline earth metal ion catalysis of alcoholysis of crown ether aryl acetates. Effect of the base-solvent system (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 663-669 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of strontium and barium ions on the acyl transfer reaction to ethoxide ion from 2-acetoxy-1,3-xylyl-15-crown-4, 2-acetoxy-1,3-xylyl-18-crwon-5, 2-acetoxy-1,3-xylyl-21-crown-6 and the model compound phenyl acetate was investigated in ethanol at 25°C. Significant catalytic effects were observed in all of the studied reactions as a result of stronger metal ion associations with the transition states than with reactants. The rate enhancements observed with the crown ether substrates are much larger than those observed with phenyl acetate, the largest acceleration being displayed by 2-acetoxy-1,3-xylyl-21-crown-6, which reacts with EtOBaBr 5 × 105 times faster than with EtONMe4. These findings provide strong evidence that cooperation of electrostatic binding to the negative charge developing at the carbonyl oxygen and coordinative binding to the polyether chain is highly efficient in the metal-bound transition state. Comparison of rate data reported here with analogous data obtained in methanol solution clearly shows that both modes of interaction contributing to the stability of the metal-bound transition state are much more efficient in ethanol than in methanol solution.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610051008
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610051101
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Mechanistic significance of the magnitude of cross-interaction constants (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 736-740 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The relationship between the magnitude of the cross-interaction constant, |ρij|, and the force constant of activation, ΔF
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610051105
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Solution conformations and hydrolytic stability of 2′ - and 3′ -substituted 2′,3′-dideoxyribonucleosides, including some potential inhibitors of human immunodeficiency virus (1992)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 5 (1992), S. 741-747 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Sugar ring conformations of a number of 2′ - and 3′ -substituted 2′,3′-dideoxyribonucleosides were determined in 2H2O by 1H NMR spectroscopy. First-order rate constants for the cleavage of their N-glycosidic bond in aqueous acid were measured. The dependence of sugar ring conformation and hydrolytic stability on the polar nature of the 2′/3′-substitutent is discussed.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610051106
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...