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
  • ZIB Catalog
  • Articles: DFG German National Licenses  (3,168)
  • 2005-2009
  • 1990-1994
  • 1985-1989  (1,430)
  • 1980-1984
  • 1965-1969  (1,314)
  • 1955-1959
  • 1945-1949  (189)
  • 1935-1939
  • 1870-1879  (235)
  • 1800-1809
  • 1987  (1,430)
  • 1968  (1,314)
  • 1946  (189)
  • 1875  (235)
  • Organic Chemistry  (1,655)
  • Chemical Engineering  (983)
  • Physics  (496)
  • Insulin
Source
  • ZIB Catalog
  • Articles: DFG German National Licenses  (3,168)
Material
Years
  • 2005-2009
  • 1990-1994
  • 1985-1989  (1,430)
  • 1980-1984
  • 1965-1969  (1,314)
    • +
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Clinical Study of glucose metabolism during partial gastrectomy (1987)
    Springer
    Journal of anesthesia 1 (1987), S. 82-87 
    Details
    ISSN: 1438-8359
    Keywords: Blood glucose ; Glucose loading ; Insulin ; Epidural anesthesia ; Upper abdominal surgery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Plasma glucose, insulin, glucagon, growth hormone (GH) and cyclic-AMP (C-AMP) were measured in 14 patients undergoing partial gastrectomy under 5 g/hr glucose loading. Seven patients received general anesthesia (GOF; Group G) and the other seven, GO + epidural anesthesia (analgesia Th4–L1; Group E). Blood glucose increased in both groups, although it remained consistently lower in Group E than in Group G. Serum IRI and IRI/glucose ratio appeared consistently higher in Group E than in Group G and a significant difference was found between the two groups at the early period of surgery. The changes in plasma glucagon and GH were found independent of those in glucose. Cyclic-AMP was also consistently higher in Group G than in Group E and a significant difference was observed at the end of anesthesia. These results suggest that epidural anesthesia with 5 g/hr glucose loading may facilitate insulin release from the islet and peripheral blood uptake particularly during the early period of surgery while many other factors such as GH, cortisol and vagal stimulation seemed to be involved in the later period of surgery. (Ogata M et al.: Clinical study of glucose metabolism during partial gastrectomy; comparison between epidural and general anesthesia. J Anesth 1: 82–87, 1987)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s0054070010082
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Influence of chronic omeprazole treatment on gastric endocrine function (1987)
    Springer
    Journal of molecular medicine 65 (1987), S. 169-173 
    Details
    ISSN: 1432-1440
    Keywords: Gastrin ; Insulin ; Omeprazole ; Somatostatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of a 4-week treatment with the substituted benzimidazole omeprazole (20 mg daily) or placebo on gastric endocrine function was tested in healthy male volunteers. Compared with placebo-treated subjects basal serum gastrin levels were slightly but significantly increased after treatment with omeprazole from 10 to 22 pg/ml (medians;P〈0.05) but returned to pretreatment values after 2 weeks recovery (9 pg/ml). Antral gastrin tissue concentration increased and was still elevated after recovery; however, antral gastrin concentrations also increased in placebo controls, and increments immediately after cessation of omeprazole treatment (2.58 µg/g; median) were not significantly over control values (1.92 µg/g;P〉0.1). Postprandial gastrin release, basal and food-stimulated insulin release, antral somatostatin concentration, and volume densities of antral G and D cells were unaffected. It is concluded that, due to incomplete inhibition of gastric acid secretion at the omeprazole dose studied, only slight effects on the endocrine stomach are to be expected after 4 weeks of administration of omeprazole.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01728228
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Relationship between blood pressure and plasma insulin in non-obese and obese non-diabetic subjects (1987)
    Springer
    Diabetologia 30 (1987), S. 719-723 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; blood pressure ; obesity ; healthy man ; oral glucose tolerance test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this study, we have measured plasma insulin at fasting and following an oral glucose load and blood pressure after glucose load in 367 (247 non-obese, 120 obese) normotensive and untreated mildly hypertensive subjects. Overall, there was no independent association between fasting plasma insulin levels and blood pressure values. After controlling for age and body weight, a significant relationship between postglucose plasma insulin levels and diastolic blood pressure was found. When non-obese and obese subjects were examined separately, significant relationships were identified between postglucose plasma insulin levels and both systolic and diastolic blood pressure values in the former but not in the latter. A comparison of sex-, age-, and weight-matched hyperinsulinaemic vs normoinsulinaemic subjects showed that the former had significantly higher values of blood pressure only if not obese. These results demonstrate that the plasma insulin response to glucose is independently correlated with blood pressure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296995
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    An examination of the role of insulin dimerisation and negative cooperativity using the biological properties of the despentapeptide and deshexapeptide insulins (1987)
    Springer
    Diabetologia 30 (1987), S. 733-738 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; despentapeptide insulin ; deshexapeptide insulin ; negative cooperativity ; insulin demerisation ; lipogenesis ; insulin binding ; insulin metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The C-terminus of the insulin B chain is essential for dimerisation and expression of negative cooperativity. In order to evaluate the possible physiological role of these phenomena, we have studied the properties in vivo and in vitro of despentapeptide insulin (B 26–30 deleted), derived from beef insulin, and deshexapeptide insulin (B25–30 deleted), derived from pork insulin. These materials do not dimerise and have 15% and 0% retention of negative cooperativity respectively. Lipogenesis potencies in rat adipocytes were: despentapeptide insulin 19.9±0.3%; deshexapeptide insulin 19.9±1.5%. Binding potencies in adipocytes were: despentapeptide insulin 22.6±7.8%; deshexapeptide insulin 13.2±3.3%. Metabolic clearance rates were reduced compared to insulin (insulin = 19.1±0.9; despentapeptide insulin = 9.7±0.8; deshexapeptide insulin = 6.4±0.6ml·min−1·kg−1 at plasma concentration 0.5 nmol/l). Hypoglycaemic potencies were reduced for both analogues (40% and 30%) when calculated on the basis of plasma concentration although both analogues and insulin were equally effective at lowering plasma glucose concentration in equimolar doses. Plasma half-disappearance time was prolonged (despentapeptide insulin=7.3±0.5; deshexapeptide insulin=9.1±0.2 min). Both analogues were full agonists and conformed to the general relationship between in vitro and in vivo properties seen with a wide range of modified insulins. They resemble other analogues with modifications which reduce receptor affinity without impairing dimerisation or negative cooperativity. The results do not support a physiological role for dimerisation or negative cooperativity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296998
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Resistance of the insulin crystal to lysosomal proteases: implications for pancreatic B-cell crinophagy (1987)
    Springer
    Diabetologia 30 (1987), S. 348-353 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; proinsulin ; crinophagy ; insulin crystals ; degradation ; lysosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Insulin is thought to be chemically stabilized within β-granules in the crystal form. The other major products of the β-granule, proinsulin and C-peptide, by contrast, are not thought able to crystallize. The physico-chemical properties of peptides in soluble or crystalline form are dramatically different. The ability of insulin to crystallize in the β-granule might thus explain why this peptide, but not proinsulin/Cpeptide, remains stable even after its introduction into lysosomes as occurs during granulolysis (crinophagy). We have now studied this by exposing proinsulin or insulin to lysosomal proteases in vitro. 125I-insulin in soluble form was found to be degraded at the same rate as 125I-proinsulin. Strikingly, however, when the labelled insulin was crystallized, its rate of degradation was decreased from 1.9 to 0.2 pmol/min. We take these data as confirmation that the insulin crystal is resistant to degradation, thereby possibly accounting for (a) the presence of insulin immunoreactivity within multigranular bodies, and (b) the unusually slow rate of degradation of insulin within B cells compared with that of other hormones in their cells of origin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00299029
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Reduction of platelet aggregation induced by euglycaemic insulin clamp (1987)
    Springer
    Diabetologia 30 (1987), S. 310-313 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; platelet aggregation ; euglycaemic clamp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To examine the effect of serum insulin independent of the level of blood glucose in vivo on platelet aggregation in healthy individuals, a euglycaemic insulin clamp was applied up to 4 h. During the clamp, blood glucose at 5.0 mmol/l and insulin levels at 100 μU/ml were maintained. Blood samples were drawn before, 2 and 4 h after the start of the insulin clamp. The platelet aggregation induced by 1 μmol/l and 2 μmol/l ADP, 1 μg/ml collagen and 2.7 μmol/l epinephrine was measured in the blood samples. Platelet aggregation induced by adenosine diphosphate, collagen and epinephrine in the 4 h sample was significantly reduced from the pre-clamp value of 8.4% to 3.9% (p〈0.05), 26.2% to 7.0% (p〈0.01) and 31.8% to 9.1% (p〈0.01), respectively. On the other hand, when the same individuals were infused with physiological saline and blood glucose (4.4 mmol/l) and insulin level (10 mIU/l) were kept within normal values, there was no difference between the values of induced platelet aggregation in samples drawn before and during the insulin infusion. It was concluded that hyperinsulinaemia reduces platelet aggregation in vivo when euglycaemia was maintained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00299023
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Insulin Wakayama: familial mutant insulin syndrome in Japan (1987)
    Springer
    Diabetologia 30 (1987), S. 87-92 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; mutant ; familial ; gene ; high performance liquid chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We describe a family from Japan displaying the mutant insulin syndrome with hyperinsulinaemia and an increased insulin: C-peptide molar ratio. Serum insulin isolated from several family members showed reduced in vitro biological activity, and analysis by high performance liquid chromatography revealed a peak co-eluting with human insulin and a second species of increased hydrophobicity co-migrating with the previously reported Insulin Wakayama. The insulin genes from the propositus were cloned and sequenced, revealing one normal allele; the second allele, encoding a leucine for valine amino acid substitution at position 3 of the insulin A chain, was similar to that previously described for Insulin Wakayama. Synthesized [LeuA3] insulin showed 0.14% of receptor binding activity on rat adipocytes and a 10-fold prolonged half-life in a somatostatin-infused dog compared with human insulin. The finding of the same mutant gene in two unrelated Japanese families suggests that Insulin Wakayama may be discovered in additional Japanese families with hyperinsulinaemia and/or diabetes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00274577
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Vertebrate insulin induces diapause termination in Pieris brassicae pupae (1987)
    Springer
    Development genes and evolution 196 (1987), S. 527-530 
    Details
    ISSN: 1432-041X
    Keywords: Insulin ; Diapause termination ; Pieris brassicae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Due to its close structural homology with the 4K prothoracicotropic hormone isolated from Bombyx mori, we tested the ability of vertebrate insulin to break pupal diapause in a Lepidopteran, Pieris brassicae. Injection of 5μg of bovine insulin in diapausing pupae led to diapause termination and synchronous adult eclosion; the effect of insulin was dose-dependent. Bovine insulin-A chain and B chain injected separately failed to show any biological activity suggesting that the intact structure of the molecule is required. Bovine insulin also promoted adult development of decapitated diapausing animals. We show that insulin triggers a reactivation of the neuroendocrine system leading to a neosynthesis of ecdysone beginning 6 days after treatment. This neosynthesis also occurred in beheaded animals suggesting that insulin stimulates the prothoracic glands without acting via the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00399877
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Haemolysis affects insulin but not C-peptide immunoassay (1987)
    Springer
    Diabetologia 30 (1987), S. 394-396 
    Details
    ISSN: 1432-0428
    Keywords: Insulin ; C-peptide ; radio-immunoassay ; haemolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Venous blood was taken at the end of a glucose infusion test in 19 individuals and divided into four aliquots, 3 of which were variably haemolysed by repeated passage through a 23-gauge needle to simulate traumatic venepuncture. Plasma insulin (measured by both a charcoal separation and a double-antibody method), C-peptide, and haemoglobin were measured in each aliquot, and haemolysis was also assessed visibly. A significant loss of immuno-assayable plasma insulin was found in samples with only a trace of visible haemolysis, with up to 90% lost in severely haemolysed samples. Plasma C-peptide was unaffected by haemolysis. This represents an additional advantage for the use of plasma C-peptide in assessing insulin secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292540
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Failure to demonstrate disruption of ultradian growth hormone rhythm and insulin secretion by dorsomedial hypothalamic nucleus lesions that cause reduced body weight, linear growth and food intake (1987)
    Springer
    Experimental brain research 66 (1987), S. 572-576 
    Details
    ISSN: 1432-1106
    Keywords: Dorsomedial hypothalamic nucleus ; Ultradian growth hormone rhythm ; Insulin ; Body weight regulation ; Food intake ; Organismic set point
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Weanling male rats received bilateral electrolytic lesions in the dorsomedial hypothalamic nuclei (DMNL rats); sham-operated animals served as controls. At the end of a 39-day postoperative period DMNL rats were lighter and shorter than controls and also exhibited significant hyopophagia. Their efficiency of food utilization (weight gained for the amount of food eaten) was normal, however. Subsequent determination of plasma growth hormone (GH) and insulin (IRI) levels every 15 min for 6-h periods from freely moving chronically cannulated rats showed no differences in pulsatile patterns and peaks of GH nor in plasma IRI levels between DMNL rats and controls. There was also no significant difference between mean 6-H GH and IRI concentrations between the two groups. The reduced body weight, length and food intake are apparently unrelated to the normal GH and IRI secretory patterns. In conjunction with previous data indicating normal somatomedin activity and normal responses to various homeostatic challenges, the data make a strong case for the argument that DMNL rats are not “growth-retarded”. Rather, they are normal animals that are “scaled-down” to a smaller size with maintenance of normal homeostatic capacity. This has been hypothesized to be due to the existence in these animals of an “organismic” set point.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270690
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    The role of opioid receptors in diabetes and hyperglycemia-induced changes in pain threshold in the rat (1987)
    Springer
    Psychopharmacology 93 (1987), S. 167-172 
    Details
    ISSN: 1432-2072
    Keywords: Opioid receptors ; Diabetes ; Hyperglycemia ; Insulin ; Naloxone ; Streptozotocin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The role of opioid receptors in diabetes and hyperglycemia-induced analgesia was studied in male Sprague-Dawley rats. Animals maintained under controlled environmental conditions were used in all studies. Pain latency was determined by the hot plate test (55° C) and analgesy-meter force method. The results of these studies indicate that streptozotocin-induced diabetic animals have a significantly higher pain threshold (P〈0.01) than the control groups. The pain threshold was found to be diurnally controlled with a peak at the beginning of the light phase (1000 hours) and a trough at the end of the dark phase (0800 hours). Diabetes-induced analgesia was found to be reversed by both acute or chronic insulin administration. In another study, glucose-induced hyperglycemic rats were found to have a significantly higher pain threshold (P〈0.01) than control animals, with a peak occurring at the beginning of the dark phase (2000 hours), and a trough at the begining of the light phase (0800 hours). The administration of the opioid antagonist naloxone (2 mg/kg) reversed the hyperglycemia and diabetic-induced analgesia. The results of these studies might indicate that analgesia found in diabetic or hyperglycemic animals may be related to the endogenous opioid system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00179928
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    The simulated dynamics of the insulin monomer and their relationship to the molecule's structure (1987)
    Springer
    European biophysics journal 14 (1987), S. 449-459 
    Details
    ISSN: 1432-1017
    Keywords: Insulin ; conformers ; molecular dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Insulin crystallizes in different forms, some of which show different conformations for the different molecules in the asymmetric unit. This observation leads to the question as to which conformation the molecule will adopt in solution. Molecular dynamics computer simulations of rhombohedral 2 Zn pig insulin have been carried out for both monomers (1 and 2) independently in order to study their behaviour in the absence of quaternary structure and crystal packing forces. These preliminary 120 ps simulations suggest that both monomers converge in solution to very similar conformations which differ from the X-ray structures of both monomer 1 and 2 (Chinese nomenclature), but are closer to the former, as has previously been suggested by an analysis of the crystal packing (Chothia et al. 1983) and by energy minimization (Wodak et al. 1984). The secondary structure of the molecules is basically preserved, as expected. A detailed description of the conformational changes is given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293254
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Interaction between endocrine and paracrine peptides in prenatal growth control (1987)
    Springer
    European journal of pediatrics 146 (1987), S. 113-122 
    Details
    ISSN: 1432-1076
    Keywords: Prenatal growth ; Nutrition ; Insulin ; Placental lactogen ; Tissue growth factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The evidence reviewed here shows that the endocrinology of fetal growth is very different from that operating postnatally. Pituitary hormones play little part in stimulating growth of the lean body mass or skeleton although growth hormone (GH) may be involved, in some as yet ill defined way in the ontogeny of the fetal pancreatic islet and insulin secretion. Insulin is important because it stimulates fetal cellular anabolism but acts in a permissive manner: with too little insulin growth is inhibited, with too much growth proceeds at a genetically predetermined rate. Placental lactogen (PL), or other peptides within the GH/PL family, may act as a true growth-promoting hormone in the fetus; it stimulates both cellular metabolism and mitosis. The part played by endocrine control mechanisms in the fetus is set in context by an appreciation of the importance of locally acting tissue growth factors, and in particular the somatomedins. Their part in fetal growth control is intimately bound up with the plane of nutrition experienced by the fetus. It is concluded that the simplest analysis that makes biological sense involves a consideration of hormones, tissue growth factors and nutrition, not hierarchically but as mutually interacting variables.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02343214
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Forskolin inhibition of hexose transport in cardiomyocytes (1987)
    Springer
    Pflügers Archiv 409 (1987), S. 158-162 
    Details
    ISSN: 1432-2013
    Keywords: Heart ; Myocyte ; Glucose ; Insulin ; Catecholimines ; Cyclic AMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of insulin, forskolin, isoproterenol, and epinephrine on 3-O-methylglucose (hexose) transport and cell cyclic AMP levels were determined in adult rat cardiomyocytes. Insulin stimulated hexose transport in these cells an average of 2.5-fold. Initial hexose transport rates at 1 mM hexose were 3.75×10−2 nmol/mg cell protein/second in the absence of insulin, and 8.25×10−2 nmol/mg cell protein/second in the presence of 12.3 μM insulin. Forskolin at 5 μM nearly abolished hexose transport within 3 s of exposure, but did not increase cell cyclic AMP concentrations within 9 s. The apparentK i for hexose transport inhibition was about 0.3 μM forskolin. Epinephrine and isoproterenol at 50 μM increased cell cyclic AMP 4-fold during 9 s exposure, but did not affect hexose transport. Treatment of cells with these catecholamines of forskolin for up to 99 s increased cell cyclic AMP, but only forskolin inhibited hexose transport. We coclude from these results that forskolin acts on hexose transport independent of its action on adenyl cyclase, and that cyclic AMP does not inhibit or stimulate hexose transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00584765
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Oxytocin-like immunoreactive nerves are associated with insulin-containing cells in pancreatic islets of anglerfish (Lophius americanus) (1987)
    Springer
    Cell & tissue research 249 (1987), S. 7-12 
    Details
    ISSN: 1432-0878
    Keywords: Anglerfish islet ; Oxytocin ; Insulin ; Innervation ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Recent reports indicate that oxytocin exerts direct effects on the release of insulin and glucagon from the endocrine pancreas of the rat. The purpose of this study was to determine whether oxytocin-like immunoreactivity is present in the anglerfish islet, and if it is associated with subsets of hormone-producing cells. Antisera against oxytocin, insulin, glucagon, somatostatin, neuropeptide Y, and the 200 — kd neurofilament polypeptide were applied to serial 5 μm sections of pancreatic islets. The antiserum to the 200 — kd neurofilament polypeptide labeled nerve bundles and axons, some of which were also stained with the oxytocin antiserum. Oxytocin immunoreactivity was observed in large nerves that branched into varicose fibers. These fibers were consistently associated only with clusters of insulin-producing cells. Successive application of oxytocin and insulin antisera to the same section provided additional verification of this relationship. Oxytocin-labeled nerves were not associated with cells immunoreactive to glucagon, somatostatin, or neuropeptide Y (anglerfish peptide Yg). The results demonstrate that oxytocin or an oxytocin-like peptide is located in fibers that surround only insulin-producing cells in the anglerfish islet. Although the functional significance of this observation remains to be determined, the results imply that oxytocin, or an oxytocin-like peptide, may affect the synthesis or release of insulin from anglerfish islets.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215412
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Insulin-, glucagonand somatostatin-like immunoreactivity in the endocrine pancreas of the lungfish,Neoceratodus forsteri (1987)
    Springer
    Cell & tissue research 248 (1987), S. 181-185 
    Details
    ISSN: 1432-0878
    Keywords: Endocrine pancreas ; Insulin ; Glucagon ; Somatostatin ; Immunocytochemistry ; Neoceratodus forsteri (Australian lungfish)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The endocrine pancreas of the Australian lungfish,Neoceratodus forsteri, was investigated immunocytochemically for the presence of polypeptide hormone-producing cells. Three cell types were identified, namely insulin-, glucagon-, and somatostatin-immunoreactive elements. The insulin cells are confined solely to the center of the islets. Glucagon and somatostatin cells are distributed peripherally around the central mass of the insulin cells. Isolated cells or clusters of glucagon and somatostatin cells are also dispersed within the exocrine parenchyma. The immunoreactive cell types are compared with those staining with standard histological procedures. The spatial relationships of the different cell populations are examined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01239979
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Localization of thyrotropin-releasing hormone-and insulin-immunoreactivity in the pancreas of neonatal rats after injection of streptozotocin at birth (1987)
    Springer
    Cell & tissue research 248 (1987), S. 89-94 
    Details
    ISSN: 1432-0878
    Keywords: TRH ; Insulin ; Pancreas ; Streptozotocin ; Regeneration ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Streptozotocin treatment at birth induces, in the pancreas of rats, first depletion of insulin and thyrotropin-releasing hormone and then early regeneration ofβ cells and insulin, but not TRH. This study was undertaken to investigate whether the reduction in pancreatic TRH content can be associated with changes in the intensity and the distribution of TRH-immunoreactivity, and to follow the pattern of regeneration ofβ cells through insulin- and TRH-immunoreactivity. In control animals, strong TRH-immunoreactivity was seen in insulin-containing cells on days 1–4 after birth. At day 7, the TRH-immunoreactivity was already decreased. In contrast, insulin-immunoreactivity was present throughout the neonatal period. A sparse population of cells near ducts also contained both TRH- and insulin-immunoreactivity at 1–2 days age. In streptozotocin-treated animals, TRH-immunoreactivity is found only in a few scattered insulin-containing cells in altered islets on days 1–4. Near the ducts, there were new insulin-containing cells which did not contain TRH. From day 7 regeneration of endocrine cells was characterized by new, typical islets, but these contained insulin-, but not TRH-immunoreactivity. These findings suggest a differential control of the biosynthesis of insulin and TRH within the pancreas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01239967
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Immunostaining of a cell type in the islets of Langerhans of the monkey Macaca irus by antibodies against S-100 protein (1987)
    Springer
    Cell & tissue research 247 (1987), S. 11-16 
    Details
    ISSN: 1432-0878
    Keywords: Islets of Langerhans ; S-100 protein ; Insulin ; Glucagon ; Somatostatin ; Pancreatic polypeptide ; Neuro-insular complex ; Monkey, Macaca irus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary S-100 protein-immunoreactive cells were demonstrated by immunocytochemical procedures in the pancreatic islets of Langerhans in the monkey Macaca irus. By use of antibodies against human S-100 protein or bovine S-100 protein, these cells were observed in all islets in the head and tail portions of the pancreas. Immunostained cells were usually located in the center of the islets or sometimes found in a more widely distributed form, but they were never arranged in a regular concentric fashion. The number of immunoreactive cells varied from one islet to another but it was relatively limited making up only 0.75%–6.3% of all insular cells. With the use of the double-immunoenzymatic procedure for demonstration of the four main endocrine cell types (insulin-, glucagon-, somatostatin-and pancreatic polypeptide producing elements), it was possible to establish that S-100 protein-immunoreactive cells represent a distinct cell type. Antibodies against S-100 protein-stained neuroinsular complexes. The present findings speak in favor of a new cell type to be added to the large variety of S-100 protein-immunoreactive cells outside the central nervous system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216541
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Effects of dietary manipulations on blood glucose and hormonal responses following supramaximal exercise (1987)
    Springer
    European journal of applied physiology 56 (1987), S. 109-114 
    Details
    ISSN: 1439-6327
    Keywords: Supramaximal exercise ; Diet ; Blood glucose ; Insulin ; Catecholamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of supramaximal exercise on blood glucose, insulin, and catecholamine responses were examined in 7 healthy male physical education students (mean±SD: age=21±1.2 years; $$\dot V_{{\text{O}}_{{\text{2 max}}} } $$ =54±6 ml · kg−1 · min−1) in response to the following three dietary conditions: 1) a normal mixed diet (N); 2) a 24-h low carbohydrate (CHO) diet intended to reduce liver glycogen content (D1); and 3) a 24-h low CHO diet preceded by a leg muscle CHO overloading protocol intended to reduce hepatic glycogen content with increased muscle glycogen store (D2). Exercise was performed on a bicycle ergometer at an exercise intensity of 130% $$\dot V_{{\text{O}}_{{\text{2 max}}} } $$ for 90 s. Irrespective of the dietary manipulation, supramaximal exercise was associated with a similar significant (p〈0.01) increase in the exercise and recovery plasma glucose values. The increase in blood glucose levels was accompanied by a similar increase in insulin concentrations in all three groups despite lower resting insulin levels in conditions D1 and D2. Lactate concentrations were higher during the early phase of the recovery period in the D2 as compared to the N condition. At cessation of exercise, epinephrine and norepinephrine were greatly elevated in all three conditions. These results indicate that the increase in plasma glucose and insulin associated with very high intensity exercise, persists in spite of dietary manipulations intended to reduce liver glycogen content or increase muscle glycogen store. These data suggest that the blood glucose increase following supramaximal exercise is most likely related to hepatic glycogenolysis in spite of a substantial decrease in liver glycogen content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00696385
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    The influence of gamma-irradiation upon the chemical and biological properties of insulin (1987)
    Springer
    Pharmacy world & science 9 (1987), S. 172-178 
    Details
    ISSN: 1573-739X
    Keywords: Chromatography ; Drug stability ; Gamma rays ; Insulin ; Sterilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Partially purified insulin preparations of bovine and porcine origin, were subjected to gamma-irradiation with doses ranging from 1.0 up to 25 kGy (0.1–2.5 Mrad) at 0
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01967537
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Complexes of 2,2′,2″-Nitrilotriphenol. Part 1. A Study of Bimolecular Nucleophilic Substitution at the Boron Atom (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 499-510 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tetradentate ligand 2,2′,2″-nitrilotriphenol forms a boron complex III with an intramolecular, transannular N→B dative bond of 1.68 Å in a strained tricyclo[3.3.3.0]undecane chelating system. The complex reacts with nitrogen bases L, such as pyridine, quinuclidine and others, to form complexes III-L, in which the intramolecular B-N bond is replaced by one between B and the external nucleophile. In solution, this displacement reaction is reversible. It was studied by temperature-dependent NMR spectroscopy. The resulting reaction and activation parameters suggest that the reaction is a bimolecular nucleophilic substitution (SN2).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700303
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Complexes of 2,2′,2″-Nitrilotriphenol. Part 3. Crystal and Molecular Structures of Three Aluminium Complexes (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 520-533 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystal and molecular structures of three Al(III) complexes of the tripod ligand 2,2′,2″-nitrilotriphenolate (I) are presented. They all show 5-coordinate Al in approximately trigonal bipyramidal geometry, with an external nucleophile X occupying the second axial position. X is OH- in[Al(I)(OH)]-[Hquin]+ (quin = quinuclidine), N in [Al(I)(py)] (py = pyridine), and one of the O-atoms of a second molecule in the dimeric [(Al(I))2]. Correlated variations in the axial bond lengths of the trigonal bipyramid are observed: [(Al(I))2]: Al-Nint. = 2.094 Å, Al-Oext. = 1.850 Å; [Al(I)(py)]: Al-Nint. = 2.153 Å, Al-Next., = 1.992 Å; [Al(I)(OH)]-: Al-Nint. = 2.278 Å, Al-Oext. = 1.765 Å. They are interpreted in terms of a dissociative reaction path at the Al(III) centre.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700305
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Molluscicidal Saponins from Swartzia madagascariensis DESVAUX (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 570-576 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The phytochemical investigation of the dried fruits of Swartzia madagascariensis (Leguminosae) afforded the five triterpenoid saponins 1-5. They were shown to be glucuronides of oleanolic acid and of gypsogenin by chemical and spectral means (FAB-MS, 13C-NMR, GC/MS). One of the isolated compounds, identified as 3-O-[O-α-L-rhamnopyranosyl-(1→3)-(β-D-glucopyranosyluronic acid)]oleanolic acid, was responsible for the high molluscicidal activity of Swartzia madagascariensis fruits against the schistosomiasis-transmitting snails Biomphalaria glabrata and Bulinus globosus.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700309
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    The Hydrolysis of Ethyl 1-Methyl-2,4-cyclopentadiene-1-carboxylate by Nonenzymatic and Enzymatic Methods. Carbon-Carbon vs. Carbon-Oxygen Bond Cleavage (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 587-592 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title ester 5 is shown to undergo C-C bond cleavage under the conditions of basic ester hydrolysis (KOH/EtOH) with formation of potassium ethyl carbonate (6) and the tautomeric methylcyclopentadienes 7 and 8. In contrast, porcine liver esterase (PLE, EC 3.1.1.1) cleanly hydrolyses 5 to give the isolable 1-methyl-2,4-cyclopentadiene-1-carboxylic acid (13). The latter undergoes thermal dimerization with conservation of the geminal-substitution pattern. The configuration of the Diels-Alder adduct 17 is ascertained by it photochemical transformation into bishomocubane dicarboxylic acid 12, easily distinguished by its C2 symmetry. Under the conditions of acid-catalyzed hydrolysis, dimerization of ester 5 and polymerization prevail, unless low acid concentration is used. The dimer 9 of 5 has one ester function that is reluctant to undergo basic hydrolysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700311
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Potassium Carboxylates by Direct Carbonylation of Potassium Alkoxides (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 593-599 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of the K+ alkoxide of linalool (1) in benzene with CO at 425-440 bar and 120-130° for 12-30 h gave the K+ salt of 2,6-dimethyl-2-vinyl-5-heptenoic acid (4a) in a ca. 25% yield based on ca. 65% converted alkoxide. Reaction of the [K+ ⊂ 18-crown-6] alkoxide of 1 with CO at 50-55 bar and 40° for 90-140 h gave a mixture containing mainly the [K+ ⊂ 18-c-6] salts of 4a (ca. 62%) and of the homogeranic acids 3a and 6a (together ca. 27% of the mixture) in a ca. 35% combined yield based on 50-60% converted alkoxide. The uncomplexed or complexed K+ alkoxide of (S)-1 gave, with ca. 85% net retention, the K+ salt of (S)-4a. Reaction of the [K+ ⊂ 18-c-6] alkoxide of geraniol (2) with CO at 50 bar and 40° for 65-70 h gave myrcene (10) and geranyl formate (11) in a ca. 40-50% yield each based on ca. 85% converted alkoxide. Reaction of the [K+ ⊂ 18-c-6] alkoxide of 3-pentyl-1,4-pentadien-3-ol (14) at 50 bar and r.t. for 70 h gave a mixture of the [K+ ⊂ 18-c-6] salts of 2-pentyl-2-vinyl-3-butenoic acid (15a) (67%) and the 4-pentyl-2,4-hexadienoic acids 18a and 19a (together 23% of the mixture) in a ca. 90% combined yield based on ca. 65% converted alkoxide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700312
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Synthesis and Copper(I) Complexes of a Series of 9- to 13-Membered N3 Macrocycles (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 680-689 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eight cyclic triamines with ring sizes between 9 and 13 were synthesized by the p-toluenesulfonate method. The open-chain triamines bis(2-aminoethyl)amine (dien) and bis(3-aminopropyl)amine (diprop) were used as starting materials. In some cases, the corresponding dimeric cyclic hexaamines have been isolated and characterized as major by-products. The complexation of Cu(I) by the triamines has been studied potentiometrically in CH3CN/H2O. All ligands L form ternary complexes [Cu(CH3CN)L]+. The corresponding association constants vary between 1011 and 107, decreasing with increasing ring size. In addition, complexes [Cu(CH3CN)yLH]2+, y = 1 or 2, are found as less important species with maximum concentrations of 7 to 50%.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700318
    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 Microstructure of Selective Palladium Hydrogenation Catalysts Supported on Calcium Carbonate and Modified by Lead (Lindlar Catalysts), Studied by Photoelectron Spectroscopy, Thermogravimetry, X-Ray Diffraction, and Electron MicroscopyThe following abbreviations and acronyms are used in the text: B. e. : Binding energy [eV], BET: Brunauer-Emmett-Teller (method of surface-area determination by physisorption of N2), AES: Auger electron spectroscopy, XPES: X-ray photoelectron spectroscopy, UPES: Ultraviolet photoelectron spectroscopy, ISS: Ionscattering spectroscopy, UHV: Ultrahigh vacuum (10-5 Pa), FTIR: Fourier-transform IR spectroscopy, TGA: Thermal gravimetric analysis, XRD: X-ray diffraction, XDA: Energy dispersive microanalysis, SEM: Scanning electron microscopy, TEM: Transmission electron microscopy, FWHM: Full width at half maximum. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 627-679 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A detailed analysis of the system Pd + Pb on CaCO3 is presented. This system known as Lindlar catalyst is used for selective hydrogenations of C≡C bonds to C=C bonds. It was found to consist of seven distinct chemical phases. Essential ingredients are solid solutions of hydrogen and oxygen in Pd. The latter phase enables the metal particles to be attached to the support via an orientational relationship calcite (113)∥Pd + O (111). The addition of Pb neither changes the micromorphology of the disk-shaped Pd particles nor does it modify the electronic structure of Pd as studied by chemisorption experiments. The addition of Pb seems to block certain active sites and, thus, to enhance the selectivity. The support was found to be a multi-domain mixture of calcite and aragonite with domain sites of several hundred Å. The free surface of the pore-free solid is covered by a calcium-hydroxide carbonate. This phase as well as several other Pb phases seem to represent only spectator materials. Verification of this as well as finding the correlation between structure and function of the various components requires a kinetic analysis which is outside the scope of this paper. It is demonstrated that a variety of analytical techniques is required to unravel the complex nature of such a ‘simple' catalyst’ as it is Pd on CaCO3.
    Additional Material: 36 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700317
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Verapliquinones: Novel Diprenylquinones from an Aplidium sp. (Ascidiacea) of Ile-Verte Waters, Brittany (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 621-626 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An Aplidium sp. (Ascidiacea), collected in French Atlantic waters near the Ile Verte, is shown to contain verapliquinone B (2) and verapliquinone D (6) as the first examples of linear diprenylquinones of the neryl type, besides their respective isomers 1 and 5 of the geranyl type.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700316
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Fe(II)-Induced Fragmentation Reaction of γ-Hydroperoxy-α,β-enones. Part 1. Synthesis of 13(14→8)-abeo-Steroids (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 701-716 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some steroidal analogues embodying the hitherto unknown 13(14→8)-abeo skeleton have been synthesized by Fe(II)-induced rearrangement (tandem β-fission/reductive alkylation) of 14α-hydroperoxy-7-en-6-ones. The configurational assignment was made by thorough analysis of NMR spectra; the structure of one of the products was unambiguously assessed by X-ray single-crystal analysis.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700320
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Light-Induced, Thermal, and Acid-Catalyzed π-Skeletal Rearrangements of Five-Ring-Annelated HeptalenesPresented in part by H.-J.H. in a lecture at the ETH in Zürich, 1985. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 742-759 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that, upon irradiation in CDCl3 solution, 5,6,8,10-tetramethylheptalene-1,2-dicarboxylic anhydride (6) rearranges to its double-bond-shift (DBS) isomer 7 in an equilibrium reaction (Scheme 2). The isomer 7 is DBS stable at -50°. At ca. 30°, a thermal equilibrium with 97.8% of 6 and 2.2% of 7 is rapidly established. Similarly, the ‘ortho’-anhydrides 9 and 11 (Schemes 4 and 5) can be rearranged to their corresponding DBS isomers 12 and 13, respectively. Whereas 12 is DBS stable at 30° (at 100° in tetralin, 94.0% of 9 are in equilibrium with 6.0% of 12), the i-Pr-substituted isomer 13 is already at 30° in thermal equilibrium with 11 leading to 98.7% of 11 and 1.3% of 13. It is shown by rearrangement of diasteroisomeric ‘ortho’-anhydrides of known relative and absolute configuration (Scheme 6) that the DBS in such five-ring-annelated heptalenes occurs with retention of the configuration of the heptalene skeleton as already established for other heptalene compounds. It is found that the DBS process may also take place under acid catalysis (e.g. HCl/CH3OH), thus yielding 9 from 12 (Scheme 9). The ‘ortho’-anhydrides 21 and 23 (Scheme 10) which are isomeric with 9 and 11 (Scheme 3) undergo rapid DBS' already at room temperature. The thermal equilibrium 21⇄22 consists of 18% of 21 and 82% of 22 at 30° and that of 23⇄24 of 17% of 23 and 83% of 24 at -30°. From these equilibrium mixtures, the pure DBS isomer 22 can be obtained by crystallization. Again, these rapid DBS' occur with retention of configuration of the heptalene skeleton (Fig. 4).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700323
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Synthese und NMR-Spektren von Nonafulven sowie Vergleich mit 10-PhenylnonafulvenHerrn Prof. Dr. Hans Nitschmann zum 80. Geburtstag gewidmet52. Mitt. über Fulvene, Fulvalene; 51. Mitt. [1]; Kurzmitt. [2]. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 862-880 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and NMR Spectra of Nonafulvene and Comparison with 10-PhenylnonafulveneExperimental procedures for the reaction of cis,cis,cis,trans-cyclononatetraenide (ccct-CNT-; see 4) with bromomethyl acetate (1a, R = H, X = Br) to give (cyclononatetraenyl)methyl acetate (5a; 84% yield) as well as for the base-induced elimination of HOAc from 5a to give nonafulvene (6a; 44% yield) are described. Spectroscopic as well as chemical evidence for 6a and 6b is presented. An approximate high-field-NMR analysis of 6a and 6b has been completed. The results are in favour of a fast interconversion of the type 6A⇄6B (Scheme 4), and supported by the MNDO-optimised geometry of 6a. The first X-ray analysis of a cyclononatetraene (i.e. of 5b) has been accomplished: 5b is a polyolefinic molecule with largely alternating bond lengths and with a nine-membered ring deviating strongly from planarity.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700327
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Field-Desorption Mass Spectra of Fern Phloroglucinols Containing Three to Six Ring ConstituentsDedicated to the late Prof. Peter Brown (12.IX.1938-15.III.1981), Dept. of Chemistry, Arizona State University, Tempe, Arizona 08521, U.S.A., Whose premature death was a great loss to his friends and collegues. The last letter which we received from him (November 15, 1980) contained the first FD mass spectra of five relatively large fern phloroglucinols which he had successfully analyzed. Two of these spectra, in which no thermal rearrangement and /or fragmentation was observed, are reproduced in this article (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 881-893 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It has been previously shown that the structural analysis of the title compounds by electron-impact ionization (EI)mass spectrometry is complicated by extensive, if not complete, thermal rottlerone-type rearrangement and/or fragmentation reactions. The use of a ‘softer’ ionization technique such as field desorption (FD) is, therefore, required in order that these compounds may be characterized in terms of their molecular size and composition. In this report, the FD mass spectra of typical representatives of this class of compounds are described along with the attempted suppression of undesirable thermal reactions by the optimization of the emitter temperatures.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700402
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Structures and Electrical Properties of Some New Organic Conductors Derived from the Donor Molecule TMET (S,S,S,S,-Bis(dimethylethylenedithio) tetrathiafulvalene) (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 942-953 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystal structures and electrical properties of radical-cation salts of the chiral organic donor TMET (S,S,S,S,-bis-(dimethylethylenedithio)tetrathiafulvalene) are described. Two structural types, 2:1 with octahedral anions Pf-6, AsF-6, SbF-6, I-3 (incommensurate), and 3:2 with tetrahedral anions BF-4, CIO-4, ReO-4 are observed. Resistivity measurements between 2 and 298 K indicate that the 3:2 types are organic metals, while the other compounds are semiconductors. (TMET)3(CIO4)2 is metallic down to about 120 K at ambient pressure and remains metallic down to 2 K at 8 kbar.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700405
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Bildung tricyclischer Thietan-Derivate durch intramolekulare(2+2)-Cycloaddition (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 992-994 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Formation of Thietane Derivatives via Intramolecular (2+2) CycloadditionOn irradiation, the two 4-vinyl-1,3-thiazole-5(4H)-thiones 1a, b, synthesized from thiobenzoic acid and the corresponding 3-amino-2H-azirines 2a,b, undergo an intramolecular (2+2)-cycloaddition reaction of the C=S and C=C bonds to give the tricyclic thietane derivatives 3a,b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700409
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Photochemical Synthesis of 2-Alkylidene-1,3-cyclocalkanediones. Preliminary Communication (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 995-996 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photolysis (λ = 254 nm) of 4-(tert-butyl)-4,6,7,8-tetrahydro-7,7-dimethy-2H-1-benzopyran-2,5(3H)-dione (3a) in t-BuOH affords 2-(2,2-dimethylpropylidene)-5,5-dimethyl-1,3-cyclohexanedione (1a) in 80% yield via homolysis of the lactone O—CO bond and subsequent ketene elimination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700410
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Some Cyclic Oligopeptide with S2n Symmetry (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1012-1016 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some cyclic oligopeptides formed by an equal number of alternating D- and L-amino-acid residues have been synthesized by using the hydrochloride of the open-chain peptide acid as precursor and the mixed-anhydride condensation method. The cyclic oligopeptides (tetra-, hexa-, and octavaline, hexaleucine, and hexaphenylalanine) form very stable H-bonded structures (IR-amide band at 3270-3290 cm-1) which are insoluble in common organic solvents. In CF3COOH/CDCI3 (25°), they yield 1H-NMR spectra snowing the expected equivalency of the various amino-acid residues.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700413
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Strukturaufklärung ungewöhnlicher Umlagerungsprodukte von S-(1-Alkenyl)sulfoximiden mit Hilfe der Stossaktivierungsmassenspektrometrie (CAD-MS) (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1041-1049 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structure Determination of Unusual Rearrangement Products of S-(1-Alkenyl)sulfoximides by Collisionally Activated Dissoication Mass Spectrometry (CAD-MS)The Molecular ions of s-(l-alkenyl)--N-(p-tolyl)sulfoximides 1 are transformed into the N(phenylsufenyl)sulfonamides 3+ by a 1,2-migration of the alkenyle group to the O-atom of the sulfoximide function followed by a 2,3-sigmatropic rearrangement. The structure of the production e has been unambiguouslydetermined by the CAD method, showing the identity of the ion e (m/z368) obtained from 1a and from 4a.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700416
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Reaktionen von 1,2-Bis(trimethylsilyl)iminen mit Selen-und Tellur-halogeniden (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1076-1078 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of 1,2-Bis(trimethylsilyl)imines with Selenium and Tellurium HalogenidesThe reactions of benzil-bis(trimethylsily)imine and phenanthrene-9,10-bis(trimethylsilyl)imine with SeOCl2, SeCl4 and TeCl4 are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700420
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Remote Tricarbonyl(diene)iron Substituent Effect on Ester Heterolysis. The Solvolyses of 5,6,7,8-Tetramethylidenebicyclo[2.2.2]oct-2-yl Methanesulfonate and of its Tricarbonyliron Mono- and Dinuclear ComplexesPart of Ph.D. thesis of J.-C. Zwick, Ecole Polytechnique Fédérale de Lausanne, 1987. Part of this work has been presented at the Fall Meeting of the Swiss Chemical Society in Bern, Oct. 10, 1986. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1079-1094 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Buffered acetolyses and hydrolyses of 5,6,7,8-tetramethylidenbicyclo[2.2.2]oct-2-yl methanesulfonate (17), of its ‘syn-endo’ (18), ‘syn-exo’ (19), ‘anti-endo’ (20), ‘anti-exo’ (21) tricarbonyliron complexes and of its ‘anti-exo,syn-endo’ (22) and ‘anti-endo,syn-exo’ (23) bis(tricarbonyliron) dinuclear complexes have been investigated (product analysis and kinetics). In contract with the solvolyses of the uncomplexed mesylate 17, the solvolyses of the complexed esters can be highly chemo- and stereoselective. The nature of the products (non-rearranged bicyclo[2.2.2]oct-2yl vs. rearranged bicyclo[3.2.1]oct-2-yl derivatives) depends on the relative configuration of the tricarbonyl(diene)iron moieties and on the medium. The rates of solvolyses of 17 are only slightly affected by complexation of one or both s-cis-butadiene units with Fe(CO)3 groups, except in the cases where the diene moiety ‘anti’ with respect to the mesylate is complexed onto its ‘endo’ face (20,23). In these cases, significant rate-retardation effects are observed, consistent with the inductive effect of the Fe(CO)3 substituent. Such retardation effects are overwhelmed by competing accelerating homoallylic participation by uncoordinated ‘anti’ -diene moieties (18,19) or, as in the case of the ‘anti-exo’-Fe(CO)3 complexes 21 and 22, by possible direct metal participation to the ionization process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700421
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Synthetic Models of the Active Site of Cytochrome P-450. 1st Communication. The Synthesis of a Doubly-Bridged Iron(II)-Porphyrin Carrying a Tightly Bound Thiolate LigandPresented in part at the ‘Gordon Research Conference’ on the ‘Chemistry and Biology of Pyrroles’, New Hampshire, 27.7.-1.8.86 (W.-D.W.), and at the ‘Swiss Chemical Society’ meeting, Bern, 10.10.86 (B.S.). (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1173-1193 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The doubly-bridged iron(II)-tetraphenylporphyrin derivative 6, carrying a sterically fixed S- ligand in the ‘proximal’ position and the substrate at the ‘distal’ site, was synthesised as an enzyme model for cytochrome P-450. Compound 36, the CO complex of 6, displays a split Soret band (403 and 457 nm) similar to the native cytochrome P-450.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700425
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Stereoselektive Alkylierung an C(α) von Serin, Glycerinsäure, Threonin und Weinsäure über heterocyclische Enolate mit exocyclischer DoppelbindungZughörige Kurzmitteilungen: [1] (Weinsäre) [2] (Threonin) [3] (Serin) [4] (Glycerinsäure).Siehe auch die Diskussionen in den vor kurzem erschienenen Übersichtsartikeln [5][6]. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1194-1216 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Steroselective Alkylation at C(α) of Serine, Clyceric Acid, Threonine, and Tartaric Acid Involving Heterocyclic Enolates with Evocyelic Double BondsThe chiral, non-racemic title acids are converted to methyl dioxolane-(cf. 13), oxazoline-(4) and oxazolidinecarboxylates (cf. 9). Deprotonation by Li(i-Pr) 2N at dry-ice temperature gives solutions of the lithium enolates A-D With exocyclic enolate double bonds. These are stable crough with respect to β-elimination (Scheme 1) to be alkylated with or without cosolvents such as HMPA or DMPU The products are formed in good to excellent yields and, with the exception of the tartrate-derived acetonlde (see Scheme 2), with diastereoselectivities above 90%. While the tartrate-and threonine-derived enolates (A and B, resp.) are chiral due to the second stereogenic center of the precursors, the serine- and glyceric-acid-derived enolates (Aand B, resp.) are chiral due to the second sterogenic center of the precursors, the serine-nd glyceric-acid-derived enolates are non-racemic due to a tert butyl-substituted (pivalaldehyde-derived) acetal center (C and D, resp.). The products of alkylation can be hydrolyzed to give α-branched tartaric acid (Scheme 2), allothreonine (Scheme 3), serine (Scheme 4), and glyceric-acid derivatives (Scheme 5) with quaternary stereogenic centers. The configurations of the products are determined by NOE-NMR measurements and by chemical correlation. These show that the dioxolane-derived enolates A and D are alkylated preferentially from that face of the ring which is already substituted (‘syn’-attack), while the dihydrooxazol-and oxazolidine-derived enolates B and C are alkylated from the opposite face (‘anti’-attack). The ‘syn’-attack is postulated to arise from strong folding of the heterocyclic ring due to electronic repulsion between the enolate π-system and non-bonding electron pairs on the heteroatoms (see Scheme 6).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700426
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Novel Synthesis of Agaritine, a 4-Hydrazinobenzyl-Alcohol Derivative Occurring in Agaricaceae (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1261-1267 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 4-hydrazinobenzyl alcohol (3 was prepared (58%)) by diiobutylaluminiumhydride reduction of methyl 4-hydrazinobenzoate (4), whereas LiA1H4 or LiBh4 reduction of4 proceeded further to yield (via intermediate 3) (4-tolyl)hydrazine (5). The alcohol 3 was stable under O2-free conditions and exhibited no tendency to eliminate H2O, neither thermally nor with H+ catalysis. Oxidation of 3 with SeO2 yielded 4-(hydroxymethyl)benzine-diazonium ion (8), identified by its azo coupling product 9 with 2-naphthol. Condensation of 3 with 1-benzyl 5-Hydrogen N-(benzyloxycarbonyl)-L-glutamate (10) in presence of dicyclohexylcarbodiimide afforded 81% of N2-(benzyloxycarbonyl)-L- glutamic acid 1-(benzyl-ester) 5-{2-[4-(hydroxymethyl)phenyl]hydrazide} (11) which upon controlled hydrogenolysis (quinoline-sulfur-poisoned Pd/C catalyst) gave 82% of L-Glutamic acid 5-{2-[4-(hydroxymethyl)phenyl] hydrazide} (1), i. e. agaritine, a metabolite of Agaricus bisporus. Without poisoning of the catalyst, hydrogenolysis of (11) yielded L-glutamic acid 5-[2-(4-tolyl)hydrazide] (12).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700505
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    The Solid and Solution Conformations of (±)-Corycavine (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1482-1486 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structure of corycavine, a protopine-type alkaloid, has been determined by X-ray analysis. A conformational feature observed is the existence of a strong electrostade interaction between the N- and C-atom at a distance of 2.618 Å. Such an interaction stabilizes the 10-membered ring conformation of the structure. Analyses of NMR spectra indicate that corycavine has the same conformation in solution as in the crystal state.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700605
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Dimethylformamide-Exchange Mechanism on Some First-Row Divalent Transition-Metal IonsPart 33 of the series ‘High-Pressur NMR Study’. Part 32: [1].Taken in part from the diploma work of C. Cossy, Université de Lausanne, 1983.This work was presented in part at the 24th International Conference on Coordination Chemistry, Athens, Greece, August 1986. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1516-1525 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of temperature on the dimethylformamide exchange on Mn(DMF)2+6 and Fe(DMF)2+6 has been studied by 13C- and 17O-NMR, respectively, yielding the following kinetic parameters: k298 equals; (2.2±0.2). 106 S-1, ΔH≠ = 34.6 ± 1.3 kJ mol-1, ΔS≠ = -7.4 ± 4.8 J K-1mol-1 for Mn2+ and K298 = (9.7 ± 0.2).105 S-1, Delta;H≠ = 43.0 ± 0.9 kJ mol-1, ΔS≠ = + 13.8 ± 2.8 J K-1mol-1 for Fe2+. The volumes of activation, ΔV≠ in cm3mol-1, derived from high-pressure NMR on these metal ions, together with the previously published activation volumes for Co2+ and Ni2+ (+2.4 ± 0.2 (Mn2+), +8.5 ± 0.4 (Fe2+) +9.2 ± 0.3 (Co2+), + 9.1 ± 0.3 (Ni2+)) give evidence for a dissociative activation mode for DMF exchange on these high-spin first-row transition-metal divalent ions. The small positive ΔV≠ value observed for DMF exchange on Mn2+ seems to indicate that a mechanistic changeover also occurs along the series, (probably from Id to D), as for the other solvents previously studied (Ia to Id, for H2O, MeOH, MeCN). This changeover is shifted to the earlier elements of the series, due to more pronounced steric crowding for dimethylformamide hexasolvates.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700608
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Two New Antifungal Naphthoxirene Derivatives and their Glucosides from Sesamum angolense WELW (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1551-1557 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two novel naphthoxirene derivatives 1 and 2 their glucosides 3 and 4 have been isolated from the root bark of Sesamum angolense Welw. (Pedaliaceae) by preparative liquid chromatography. The structure of 1 was established by X-ray diffraction analysis. The identities of the other naphthcxirenes were deduced by spectroscopic (IR, UV, 1H-NMR, 13C-NMR, EI-MS, DCI-MS) and chemical methods (oxidation, acid and enzymatic hydrolysis). Compounds 1-3 exhibited antifungal activity. Naphthoxirene 1 was, in addition, cytotoxic to human colon carcinoma cells.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700613
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    On Negative Birefringence in Water-in-Oil Microemulsions (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1531-1536 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The occurrence of a negative birefringence in water-in-oil (W/O) microemulsions has been substantiated and analyzed. The analysis is based on the well-established aqueous nanodroplet model of W/O microemulsions. In the particularly investigated water/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/aliphatic oil systems, the AOT monolayer exhibits a negative induced intrinsic birefringence, which is brought about by the pronounced polarizability of the alkyl moiety of the AOT molecule approximately perpendicular to the direction of its permanent dipolement.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700610
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Erratum (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 2246-2246 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700829
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Mitteilungen - Communications (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 2305-2306 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700830
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Herstellung und Charakterisierung in Membranen von Ionophoren mit Selektivität fü Natrium-Ionen (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 153-157 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preparation of Neutral Sodium-Selective Ionophores and their Characterization in Membrane ElectrodesDifferent ionopbores based on N,N′-dibenzyl-N,N′-diphenyl-1,2-phenylenedioxydiacetamide (1) have been prepared by substitution of the aromatic ring carrying the ether O-atoms. Substituents of widely different electronegativity (CH3, CH3O, CHO, CN NO2, Br) do not relevantly influence the ion selectivity.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700119
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Complexes of 3,3′-Oxybis[(diphenylphosphino)methylbenzene] with Ni(II), Pd(II), Pt(II), Rh(I), and Ag(I). How Important is Backbone Rigidity in the Formation of trans-Spanning Bidenatate Chelates?? (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 158-170 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bidentate diphosphine ligand, 3,3′-oxybis[(dipenylphosphino)methylbenzene] (1) forms monomeric, trans-square-planar complexes MX2(1) (M = Ni, Pd, Pt; X = Cl-, Br- I-, and, in part, N3-, NCS-, CN-, NO3-) as well as Pt(H)Cl(1), Pt(H)Br(1), and RhCl(CO)(1). Polymeric species have been observed with substitutionally inert metal centres: trans-[PtCl2(1)]2 and cis-[PtCl2(1)]n (mean value of n ≈ 4-5) 31P-NMR, and selected IR and UV/VIS parameters are reported. Ligand 1 shows a marked preference for trans-spanning and monomeric chelate formation, despite its various degrees of freedom of internal rotation in the lignad backbone. The readily available ligand 1 as well as analogues with other donor atoms, therefore, appear useful in most potential applications of trans-spanning chelate ligands. The crystal structure of AgCl(1)·0.5 (CH3)2C=O·0.39 C6H12 (space group C2/c,a = 21.02 Å, b = 14.57 Å, c = 24.79 Å, β = 99.77°, V = 7531.4 Å3, Z = 8) confirms the presence of three-coordinate Ag(I), with a coordination intermediate between a trigonal-planar and a T-shaped geometry (P-Ag-P = 145.61(8)°).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700120
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Aza-2-dienes-1,3. Partie 5. Préparation de N-aminoimidazoles, 3H-pyrroles, triazolo[1,2,4][1,5-a]pyrazines et imidazo[1,2-a]pyrazines (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 187-195 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Aza-1,3-dienes. Access to N-Aminoimidazoles, 3H-Pyrroles, [1,2,4]Triazolo[1,5-a]pyrazines, or Imidazo[1,2-a]pyrazinesNucleophilic attack of 5-(dialkylamino)-2-aza-1,3-diene-1,1-dicarbonitriles (or their 1-methoxycarbonyl analogous) by hydrazines or hydrazdes gives substituted N-aminoimidazoles, [1,2,4]triazolo-[1,5-a]pyrazines, or α-dihydrazino derivatives. With α-amino esters (or analogous), imidazo[1,2-a]pyrazines are produced. Addtion of cyanide anions occurs also with formation of substituted 3H-pyrroles. Structures and rationalisation of this nucleophilic attack are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700123
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Syntheses of Tetrahydrolipstatin and Absolute Configuration of Tetrahydrolipstatin and Lipstatin (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 196-202 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Lipstatin (1), a natural product, and tetrahydrolipstatin (2) are pancreatic lipase inhibitors. Non-stereoselective and partially stereoselective syntheses of 2 are used to establish the absolute configuration of tetrahydrolipstatin and lipstatin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700124
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Ring-Open Analogues of Adenine Nucleoside. Aminoacyl Derivatives of Cyclo- and Acyclo-Nucleosides (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 219-231 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of acyclic analogues of ribo- and deoxyribonucleosides is described. These compounds (Table 3) are both poor substrates and poor inhibitors of adenosine deaminase. The synthesis of dinucleotides from these analogues is also described, and the activity along with the inhibitory properties of some of them are studied against deaminase enzyme. These nucleotides are resistant to degradation by phosphodiesterases. HCl impregnated on silica gel is an excellent reagent for the preparation of the chloromethyl ether precursors of acyclo-nucleosides. A general and rapid procedure is developed for the preparation and isolation of the 5′-aminoacyl derivatives of robo- and arabinonucleosides. Quinoline has a marked effect on aminoacylations without racemization. Compounds 35a, b possess remarkable antiviral effects in vitro. A procedure is also developed for the conversion of acyclo-ribonucliosides 13e, f to acyclo-deoxyribonucleosides 11e, f.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700127
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Functionalisation of saturated hydrocarbons. Part 9Part 8:[1].. Oxidation of patchouli alcohol by the ‘gif system’: Isolation and organoleptic properties of three new ketonic derivativesDedicated to Prof. Vlado Prelog on the occasion of his 80th birthday (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 273-280 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidation of patchouli alcohol (1) using the ‘Gif system’ afforded as major isolated products three new ketonic derivatives 16-18. The structures of these compounds were established by spectral techniques including 2D-NMR. Ketones 16-18 display interesting organoleptic properties.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700202
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Synthese von ω-(5-Oxo-1-cyclopentenyl)alkansäure-methylestern aus 2-Nitrocycloalkanonen (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 315-320 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of Methyl ω-(5-Oxo-1-cyclopentenyl)alkanoates Starting from 2-NitrocycloalkanonesA convenient synthesis of methyl ω-(5-oxo-1-cyclopentenyl)alkanoates 1 is described. 2-Nitrocycloalkanones 2 are converted to 2-(3,3-dimethoxypropy1)-2-nitrocycloalkanones 4. Treatment of 4 with MeOH/MeONa led to the ring-opened nitronates 5 which underwent a Nef reaction to form the corresponding oxo derivatives 6. Partial hydrolysis of followed by base-catalyzed aldol reaction gave the desired products in high yields.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700207
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Cyclobut-2-enones from Alkynes via Dichlorocyclobut-2-enonesIn part taken from the Ph.D. thesis of A.A.A., University of Zürich, 1986. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 321-328 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The [2 + 2]-cycloaddition of dichloroketene (prepared in situ from CCl3COCl and Zn(Cu)) with three alkynes 1a-c to form 2,3-dimethyl-(2a), 2,3-diethyl-(2b) and 3-butyl-4,4-dichlorocyclobut-2-enone (2c) proceeds rapidly in the absence of POCl3. The primary products 2a-c rearrange in situ to the 2,4-dichlorocyclobut-2-enones 3a-c under the influence of ZnCL2 produced during the reaction. ZnCl2 converts both 2a and 3a into a 4:6 equilibrium mixture of the two; this isomerization does not occur with LiCl. The Cl-atoms of both 2a, b and 3a, band of 2c may reductively be removed with Zn(Cu) in AcOH/pyridine to afford the alkylcyclobutenones 4a-c. Without pyridine, this reduction gives ca. 1:1 mixtures of the double-bond isomers 4 and 5 in low yields. The cyclobutenones 2c and 4c may be deuterated by CD3COOD in the presence of pyridine. D-Atom is introduced into 2c at C(4) and at C(γ), and into 4c at C(2) and C(4). A mechanism for this deuteration is considered, which does not involve a cyclobutadienolate 7, but rather a cyclobutenolate of type 8. The reductions of 2 and 3 to 4 might also pass through the same type of intermediate 8.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700208
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    3-(Dimethylamino)-2,2-dimethyl-2H-azirin als α-Aminoisobuttersäure(Aib)-Äquivalent: Cyclische Depsipeptide durch direkte Amid-CyclisierungVorläufige Mitteilung s. [1]; vgl. auch [2]. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 329-338 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-(Dimethylamino)-2,2-dimethyl-2H,-azirine as an α-Aminoisobutyric-Acid (Aib) Equivalent: Cyclic Depsipeptides via Direct Amid CyclizationIn MeCN at room temperature, 3-(dimethylamino)-2,2-dimethyl-2H-azirine (1) and α-hydroxycarboxylic acids react to give diamides of type 8 (Scheme 3). Selective cleavage of the terminal N,N-dimethylcarboxamide group in MeCN/H2O leads to the corresponding carboxylic acids 13 (Scheme 4). In toluene/PhSH, phenyl thioesters of type 11 are formed (see also Scheme 5). Starting with diamides 8, the formation of morpholin-2,5- diones 10 has been achieved either by direct amide cyclization via intermediate 1,3-oxazol-5(4H)-ones 9 or via base-catalyzed cyclization of the phenyl thioesters 11 (Scheme 3). Reaction of carboxylic acids with 1, followed by selective amide hydrolysis, has been used for the construction of peptides from α-hydroxy carboxylic acids and repetitive α-aminoisobutyric-acid (Aib) units (Scheme 4). Cyclization of 14a, 17a, and 20a with HCI in toluene at 100° gave the 9-, 12-, and 15-membered cyclic depsipeptides 15, 18, and 21, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700209
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Synthese von 2-Hydeoxy-3-methyl-2-hexen-4-olid (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 369-374 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 2-Hydroxy-3-methyl-2-hexen-4-olidThe title compound 13a, a substance used in food-flavoring, was synthesized in 89% overall yield, starting from methyl 2-hydeoxy-3-butenoate (3a). The key step in this transformation is the isomerization of the C=C bond in 3a which yielded methyl 2-oxobutanoate as an intermediate. The latter underwent a self-condensation yielding 2-hydroxy-4-(methoxycarbonyl)-3-methyl-2-hexen-4-olid (11a), which, after hydrolysis and decarboxylation, gave 13a. In addition, the syntheses of five other compounds related to 13a are reported.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700214
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Triaziridine 7. Mitteilung6. Mitteilung: [1].. Stabile pyramidale Konfigurationen an den Stickstoff-Atomen von Dialkyl-und Trialkyl-triaziridinen (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 381-389 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Stable Pyramidal configurations at the Nitrogen Atoms of Dialkyl-and Trialkyl-triaziridinesStereochemical features of the recently synthesized nine samples of di- and trialkyl-triaziridines, namely the 1,3-cyclopentylen-(series a) and the two stereoisomers of the diisopropyl derivatives (series b and c), containing as the third substituent an H-atom (2), a CH3 group (3)or a CH2OH group (4), were elaborated on the basis of the 1H-, 13C-, and 15N-NMR spectra. The three N-atoms of the saturated N3-homocycle were found to be stable to pyramidal inversion in all cases. According to their NMR spectra, 2-4 of the series a and b possess twofold symmetry (Cs), while 2-4 of series c are asymmetric. Thus, series c has the trans-configuration at N(2)/N(3) and, consequently, the cis-configuration at N(1)/N(2), while series a and b have the cis-configuration at N(2)/N(3) and -since the all-cis-arrangement is excluded-the trans-configuration at N(1)/N(2). The asymmetry of the trans-configurated 2c turned into twofold symmetry (C2), when a little CF3COOH was added. The 1H- and 13C-NMR data of series b and c of our alkyl-triaziridines exhibit a shielding effect, according to which there are two types of i-Pr groups, i-Pr(a) and i-Pr(b). They differ in the NMR signals of the H- and the C-atoms of their CH groups: the H-atoms of i-Pr(a) are more deshielded by 0.75-1.111 ppm and its C-atoms are more shielded by 10.0-160.0 ppm as compared to the corresponding atoms of i-Pr(b). i-Pr(a) is cis (on the N3-homocycle) to a large substituent (such as i-Pr, Me, CH2OH) and to a lone pair, while i-Pr(b)is cis only to a small (H) or to no substituent and to one or two lone pairs. An analogous effect appears in the NMR signals of the CH3 and CH2OH groups at N(1) of 3 and 4 in the series b and c.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700216
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Synthese eines Nickel(II)-B,C,D-hexadehydrocorrinats durch (A→D)-CyclisierungKurzmitteilung: [1].Professor Dr. Gerhard Quinkert zum 60. Geburtstag gewidmet (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 402-411 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of a Nickel(II) B,C,D-Hexadehydrocorrinate by (A→D)-Ring ClosureThe B,C,D-hexadehydrocorrin of type 10 fills a gap in the corrin family whose members can occur at different oxidation levels. We report here on the synthesis of a correspondingly protected secocorrin 23 and its convenient cyclization to 10
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700219
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Studies on the Biosynthesis of Tabtoxin (Wildfire Toxin). Origin of the Carbonyl C-Atom of the β-Lactam Moiety from the C1-Pool (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 412-422 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Re-isolation of Pseudomonas tabaci strain NCPPB 2730 from its host, the tobacco plant, led to an activation of the bacteria in order to produce the β-lactam dipeptide tabtoxin (Wildfire toxin, 1). Incorporation of several 14C-labelled amino acids as well as L-[methyl-13C]methionine, L-[1,2-13C2]- and L-[3,4-13C2]aspartate, rac -[1,2-13C2]glycerol, and [1,2-13C2]acetate into isotabtoxion (2) demonstrated that the building blocks of tabtoxin (1) are L-threonine, L-aspartate, the Me group of L-methionine and a C2-unit derived from the C3-pool (Fig. 3). The Me group of L-methionine provides the carbonyl C-atom of the β-lactam moiety. These findings represent a novel pathway in β-lactam biosynthesis. Mechanistic aspects with respect to the β-lactam ring formation are discussed. A biradical 16 is proposed as an intermediate during the cyclization of a N-formyl-α-amino ketone 15.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700220
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Mitteilungen - Communications (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 488-491 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700229
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    On the Purported Structure of Cyclodeca[1,2,3-de: 6,7,8-d′e′]dinaphthalene (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 480-487 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of the bis(sulfonium salt)7 in a solution of Na2CO3 in H2O/EtOH yielded three main products 8-10. The spectroscopic data of 8 were identical to those which led Mithcell and Sondheimer to assign them to cyclodeca[1,2,3-de: 6,7,8-d′e′]dinaphthalene (3). Our investigations show, however, that the correct structural assignment leads to the structure of 7,7a-dihydrodibenzo[de,mn]naphthacene (8).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700228
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987) 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700101
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Mehrstufige Redoxsysteme. XLIX. MitteilungXLVIII. Mitteilung:[1]. Mit π-Systemen substituierte 1,3-Dimethylidencyclobutane: Synthese und Eigenschaften (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 929-941 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Multistep Redox Systems. 1,3-Dimethylidenecyclobutanes Substituted by π-Syntheses and PropertiesAs potential redox systems 1,3-dimethylidenecyclobutanes are synthesized in which the ‘exo’-methylidene group participates in a cyclopentadienyl (typeC4)or cycloheptatrienyl (type A5) system. Benzo-annellated systems are also described. The formation of the C=C bond by the reaction of thioketones (3 and 31) with diazo compounds is extended to extended to 1,6,7,21, and 24, which so far had not been employed. In some cases, intermediate thiiranes can be isolated (e.g.4) which are smoothly transformed into the target compounds of types C4 and A5 by extrusion of sulfur. The new C=C bonds may be introduced stepwise, thereby allowing the synthesis of unsymmetrically substituted 1,3-dimethylidenecyclobutanes (e.g. 20 and 35). Reduction of by Na does not produce bicyclobutanes but compounds 43 and 44 with one dihydrofulvene unit.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700404
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Verecynarmin A, a Novel Briarane Diterpenoid Isolated from Both the Mediterranean Nudibranch Molluse Armina maculata and its Prey, the Pennatulacean Octocoral Veretillum cynomorium (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 984-991 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The briarane diterpenoid verecynarmin A (=(-)).(8R,9S,11R,12aR,4Z,6Z)-11,12-epoxy-8,8a,9,10,12,12a,13-octahydro-1,5,8a,12-tetramethylbenzo[4,5]cyclodeca[1,2-b]furan-9-yl acetate; ((-)-1) is shown to be contained in both the Mediterranean nudibranch mollusc Armina maculata(RAFINESQUE) and its prey, the pennatulacean octocoral Veretillum cynomorium(PALLAS). The structure is mainly solved by 1D-NMR, 2D-NMR, and NOE studies of (-)-1. However, the relative configurations at the epoxide and angular methyl centres, as well as the preferred conformation, are established by shift-reagent and NOE studies of diol(-)-4 obtained by epoxide-ring opening of (-)-1 with LiA1H4. The absolute configuration is established via deacetylation of (-)01 followed by Horeau's esterification.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700408
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Oxidationsreaktionen methyl-substituierter 2,1,3-Benzothiadiazole und 2,1,3-Benzoselenadiazole mit Selen-dioxid (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 997-1000 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxidation Reactions of Methyl Substituted 2,1,3-Benzothiadiazoles and 2,1,3-Benzoselenadiazoles with Selenium DioxideThe synthesis 5-8 by oxidation of 4-methyl-(1),5-methyl(2), 5,6-dimethyl-2,1,3-benzoselenadiazole (3), and 5,6-dimethyl-2,1,3-benzothiadiazole (4), respectively, with selenium dioxide as well as their spectroscopic properties are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700411
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Steric Effects on Reaction Rates. Part IX. Force-Field Parameters for Bridgehead and Rigid Tertiary Carbenium Ions (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1017-1024 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular-mechanics calculations for strain of carbenium ions are tested using Bentley's unified reactivity scale for bridgehead solvolysis as reference. Excellent correlations are obtained for solvolytic bridgehead reactivity with the calculated steric-energy difference (ΔEst) between substrate (R—H or R—OH) and cation (R+). After adjustment of appropriate force-field parameters, the approach is successfully extended to the rigid, but planar cations derived from structures 15-20; however, the general set of parameters cannot be applied to highly strained systems such as the cation formed from 17. With all of the 18 sets of parameters tested, the 2-endo-norbornyl derivative 16, is adequately correlated, while the exo isomer 15 exhibits enhanced reactivity by a factor of ca. 102 to 103.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700414
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Complexes of 2,2′,2″-Nirtilotriphenol. Part IV. Cage Compounds with Phosphorus(III) and Phosphorus(V) (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1063-1069 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ligand 2,2′,2″-nitrilotriphenol reacts with P(III) and P(V) compounds to form corresponding phosphorus complexes. Syntheses and NMR data of 2,2′,2″-nitrilotriphenyl phosphite (II), 2,2′,2″-nitrilotriphenyl phosphate (III) and of a hydrolysis product of II, 2,2′-[N-(2-hydroxyphenyl)imino]diphenly phosphonate (IV), are reported, as well as crystal structures of II and IV. Phosphite II shows a bicycloundecane framework; no NċPinteraction is present. The phosphonate IV shows two coordinated and one dangling phenol group; the N-atom does not interact with the P-atom. Strong acids protonate II as well as III to form cations: in these, NMR evidence indicates coordination of the N-atom to the P-atom.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700418
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Octacarbonyldicoblat-Inauced (1,3) H Shits in 1-Methylallenecarboxylates and Allenic LactonesDedicated to Professor Dr. André S. Dreiding (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1070-1075 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The allenecarboxylates 1a,b and allenic lactones 4a,b undergo thermally induced (1,3) H Shifts in the presence of Co2(CO)8. The non-isolated 1,3-dienes 2a,b react further affording the Diels-Alder Adducts 3a,b Scheme 1 in high yields. These adducts were not formed in the case of the 2-vinybutenolides 5a,b. On irradiationin the presence of Co2(CO)8 or Mn2(Co)10, the studied allenes reacted in a different manner, yielding either cyclization products 7 and 8 (Scheme 3) or products 9 and 10, formed via H abstracton and solvent addition (Schemes 4 and 5).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700419
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Brominations of Cyclic Acetals from α-Amino Acids and α- or β-Hydroxy Acids with N-Bromosucinimide (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1104-1114 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The preparation of novel electrophilic building blocks for the synthesis of enantiomerically pure compounds (EPC) is described. Thus, the 2-(tert-butyl)dioxolanones, -oxazolidinones, -imidazolidinones, and -dioxanones obtained by acetalization of pivalaldehyde with 2-hydroxy-, 3-hydroxy-, or 2-amino-carboxylic acids are treated with N-bromosuccinimide under typical radical-chain reaction conditions (azoisobuytyronitril/CCl4/reflux). Products of bromination in the α-position of the carbonyl group of the five-membered-ring acetals are isolated or identified (2, 5, and 8; Scheme 1). The dioxanones are converted to 2H, 4H-dioxinones under these conditions (12, 14, 15, 21, and 22; Schemes 2 and 3). The products can be converted to chiral derivatives of pyruvic acid (methylidene derivatives 3 and 6) or of 3-oxo-butanoic and -pentanoic acid (16 and 23). The mechanism of the brominations is interpreted. The conversion of serine to enactiomcrically pure dioxanones 26-28 (Scheme 4) is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700423
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Addendum (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1229-1229 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700428
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Mitteilungen - Communications (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1230-1231 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700429
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Enzyme-Catalyzed Hydrolysis of Some Functionalized Dimethyl MalonatesPresented at the meeting of the Swiss Chemical Society, Berne, October 10, 1986. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1250-1254 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is described for the preparation of (+)-(R)-methyl hydrogen 2-(tert-butoxymethyl)-2-methyl-malonate (5e) in synthetically useful amounts from readily available starting material.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700503
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Diels-Alder-Reaktionen von 2,4-Bis{[(tert-butyl)dimethylsilyl]oxy}-3-aza-1,3-pentadien mit HeterodienophilenTeil der geplanten Dissertation von U. R. [1]. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1255-1260 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diels-Alder Reactions of 2,4-Bis{[(tert-Butyl)dimethylsilyl]oxy}-3-aza--1,3-pentadien with HeterodienophilesThe 2,4-bis{[(tert-butyl)dimethylsilyl]oxy}-3-aza-1,3-pentadien(2) reacts via the Diels-Alder adducts 3, 6a-c, and 8a, b, which cannot be isolated, giving the triazines 4, 7a-c, and the oxadiazines 9a, b. The hydrolysis of 4 in MeOH affords the N-acetyl-acetamid derivative 5. The formula of 9a is proven by an X-ray-structure analysis.
    Notes: No. Abstract.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700504
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Zwei weitere Iridoid-glycoside und ein Monoterpen-glycosid aus Sambucus ebulus L. (Caprifloiaceae). 3. Mitteilung über die Inhaltsstoffe der Zwergholunderwurzel (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 91-101 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Iridoid Glycosides and a Monoterpene Glycoside from Sambucus ebulus L. (Caprifloiaceae)From the roots of Sambucus ebulus L., two novel valeriana-type ester iridoid glycosides, 6′-O-apiosylebuloside (1) and 7,7-O-dihydroebuloside (3), along with the open-chain monoterpene glycoside 5 were isolated. Their structure elucidation is based mainly on one- and two-dimensional NMR methods. 1H,1H-COSY experiments permitted complete assignment of signals arising from the disaccharide unit in 1. Biogenetically, 3 seems to represent the equivalent of loganin in the valeriana-type series of iridoid glycosides.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700111
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Synthese von ‘D-Isothreonin’ und ‘L-Alloisothreonin’ aus L-Alanin (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 116-120 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of ‘D-Isothreonine’ and ‘L-Alloisothreonine’ Starting from L-AlanineStarting from L-alanine, ‘D-isothreonine’ ( = (2R, 3S)-3-amino-2-hydroxybutanoic acid) and ‘L-alloisothreonine’ ( = (2S, 3S)-3-amino-2-hydroxybutanoic acid) were synthesized.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Oxidative Breaking of Long-Chain Acetylenic Enol Ethers of Glycerol of the Marine Sponges Raspailia pumila and of Model Compounds with Aerial Oxygen (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1400-1411 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The raspailynes (novel long-chain enol ethers of glycerol having the enol ethers double bond conjugated in sequence, to an acetylenic and an olefinic bond, isolated from the North-East-Atlantic sponges Raspailia pumila and R. ramosa) are stable under normal hydrolytic conditions for enol ethers. In contrast, when their solutions are evaporated, these lipids such as raspailyne Bl (=(-))-3-[(1Z,5Z)-(tetradeca-1,5-dien-3-ynyl)oxy]-1,2-propanediol;(--2) rapidly react with aerial O2 under normal laboratory-daylight conditions, with rupture of the C=C enol ether bond to give 1-O-formylglycerol (3) and an aldehyde (such as tridec-4-en-2ynal(4) from (-)-2). This reaction must be caused by triplet O2, since thermally generated singlet O2 has no effect on (-)-2 in solution. That the mere presence of an enol-ether moiety conjugated to an acetylenic group is responsible for such a behaviour is demonstrated with the model compounds 1-methoxypentadec-1-en-3-yn-5-ol (6a) and its 5-O-acetyl or 5-O-tetra-hydropyranyl derivatives 6b and 6c, respectively. Resistance to both hydroytic conditions and singlet O2 of these compounds is thought to arise from electron depletion at the enol-ether C(beta;) atom by the acetylenic group. Plausible reaction pathways for enol-ether bond rupture in these compounds by aerial O2 are outlined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700521
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Catalytic Intramolecular Palladium-Ene Reactions. Preliminay CommunicationPresented at the ‘4th IUPAC-Symposium on Organometallic Chemistry Directed towards Organic Synthesis’ (OMCOS IV), July 28, 1987, Vancouver, Canada. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1477-1481 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pd(dba)2[dba = dibenzylideneacetone]/PPh3-or Pd(PPh3)4-catalyzed cyclizations of acetoxy-dienes 2 → 3 and 10 → 11 gave 1-vinyl-2-methylidene-subsituted cyclopentances and cyclohexanes in high yield, consistent with a palladium-ene/β-elimination mechanism (D → E → F, Scheme 2). The efficient and highly stereoselective cyclizations 7 → 7 and 8 → 9 illustrate intramolecular allylpalladium insertions into 1,2-dialkyl-, trialkyl-, trialkyl-, and cyclic alkenes followed by elimination of the exocyclic β-H giving 1,2-divinylcyclopentanes. These new olefin insertions proceed faster in AcOH (compared to THF) and occur preferentially cis relative to the Pd (13 → 14 → 15).
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700604
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Drug-induced modifications of the immune response part 9Part8: [1]4-(Arylamino)-2,5-dihydro-2-oxo-N-(trans-2-phenylcycolopropyl)furan-3-carboxamides as Novel Antiallergic Compounds (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1526-1530 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and antiallergic activity of a series of 4-(arylamino)-2,5-dihydro-2-oxo-N-(trans-2-phenyl-cyclopropyl)furan-3-carboxamides 10 are described. Treatment of N-substituted 2-amino-4,5-dihydro-4-oxofuran-3-carboxylic acids 9 with chlorooxobis(2-oxo-1,3-oxazolidin-3-yl)phosphorus (2) and an appropriate aromatic amine in the presence of Et3N, resulted in a novel 3(2H)-furanone-→2(5H)-furanone rearrangement that led to the facile preparation of the new amides 10. The latter exerted a potent antiallergic activity when tested in the dermal vascular permeability and active anaphylaxis assays in rats. The most active compound 10b inhibited the action of serotonin, histamine, and bradykinin by 94, 92, and 100%, respectively, when administered intraperitoneally to rats at doses of 100 mg/kg. The present series of 10 represents a novel class of antiallergic agents.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700609
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Notiz über die Verwendung von 3-(Arylsulfonyl)-2-cycloalkenonen als 2-Cycloalkinon-Synthese-Equivalente (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1537-1539 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Note on the Use of 3-(Arylsulfonyl)-2-cycloalkenones as Synthesis Equivalents of 2-Cycloalkynones3-(Arylsulfonyl)-2-cyclopentenones and 3-phenylsulfonyl-2-cyclohexnone undergo Diels-Alder reactions with cyclopentadiene. Elimination of arylsulfinic acid leads to products, which would have been obtained directly from a Diels-Alder reaction of 2-cyclopentynone or 2-cyclohexynone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700611
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Inhibition of Electron-Hole Recombination in Substitutionally Doped Colloidal Semiconductor Crystallites (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1596-1604 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The subtitutional doping of 120-Å- sized TiO2 Particles with Fe(III)ions has a profound effect on the charge carrier recombination time in this colloidal semiconductor. In undoped particles, the mean lifetime of an electronhole pair is ca. 30 ± 15 ns. Doping with 0.5% Fe(III) drastically augments the charge-carrier lifetime which is extended to minutes or hours. The slow character of the recombination dynamics in Fe(III)-doped colloids was confirmed by laser photolysis using the characteristic optical of electrons in TiO2 to monitor the time course of the reaction. EPR studies showed the Fe(III) ions to enter the host lattice on Ti(IV) sites, charge compensation taking place through the formation of oxygen vacancies. Valence-band holes produced under band-gap excitation react with these centers it the bulk forming Fe(IV), the conduction band electrons being trapped by Ti(IV) at the particle surface. Presumably, the spatial separation of the trapped electron and hole sites inhibits their recombination.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700617
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    The Radical Anions of 1,2-diphenylcyclohexene and Structurally Related Compounds. Conformational ESR and ENDOR studies (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1558-1568 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ESR, ENDOR, and TRIPLE resonance studies have been performed on the radical anions of 1,2-diphenylcyclohex-1-ene (4), 1,2-di(perdeuteriophenyl)cyclohex-1-ene ((D10)4) the trans-configurated 3,4-diphenyl-8-oxabicyclo[4.3.0]non-3-ene (5) and its 2,2,5,5-tetradeuterio derivative (D4)5, and 2,3-diphenyl-8,9,10-trinorborn-2-ene (6). The spectra of \documentclass{article}\pagestyle{empty}\begin{document}$ 4^{- \atop \dot{}} $\end{document} exhibit strong temperature dependence along with a specific broadening of ESR hyperfine lines and proton ENDOR signals. The coupling constant, which bears the main responsibility for these features, is that of the β-protons in the quasi-equatorial positions of the cyclohexene ring, and the experimental findings are readily rationlized in terms of relatively modest conformational changes without invoking the inversion of the half-chair form. The hyperfine data for the β-protons in \documentclass{article}\pagestyle{empty}\begin{document}$ 5^{- \atop \dot{}} $\end{document} closely resemble the corresponding low-temperature values for \documentclass{article}\pagestyle{empty}\begin{document}$ 4^{- \atop \dot{}} $\end{document}, However, the ‘unusual’ features observed for \documentclass{article}\pagestyle{empty}\begin{document}$ 4^{- \atop \dot{}} $\end{document} are absent in the ESR and ENDOR spectra of \documentclass{article}\pagestyle{empty}\begin{document}$ 5^{- \atop \dot{}} $\end{document}, because the half-chair conformation of the cyclohexene ring in \documentclass{article}\pagestyle{empty}\begin{document}$ 5^{- \atop \dot{}} $\end{document} is deprived of its flexibility. Although the boat form of this ring in \documentclass{article}\pagestyle{empty}\begin{document}$ 6^{- \atop \dot{}} $\end{document} is also rigid, the spectra of \documentclass{article}\pagestyle{empty}\begin{document}$ 6^{- \atop \dot{}} $\end{document} are temperature-dependent, due to an interconversion between two propeller-like conformations of the phenyl groups. The pertinent barrier is 30 ± 5 kJ·mol-1. An analogous interconversion presumably takes place in \documentclass{article}\pagestyle{empty}\begin{document}$ 4^{- \atop \dot{}} $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 5^{- \atop \dot{}} $\end{document} as well, but, unlike \documentclass{article}\pagestyle{empty}\begin{document}$ 6^{- \atop \dot{}} $\end{document}, it is not amenable to experimental study.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700614
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Synthesis and Formation of Ironcarbonyl Complexes of 3′,3′-Dimethyl-2,3,5,6-tetramethylidenespiro[bicyclo[2.2.1]heptane-7,2′-oxirane]. Single-Crystal and Molecular Structure of syn,exo2,3-anti,endo5,6-trans-μ-[(1r,2r,3s,4s,5s,6r)-c,2,3,c-η:c,5,6,c-η-(3′,3′-dimethyl-2,3,5,6,-tetramethylidenespiro[bicyclo[2.2.1]heptane-7,2′-oxirane])]bis(tricarbonyliron)Interaction between non-conjugated chromophores, Part 27. Part 26, see [1]. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1638-1648 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 3′,3′-dimethyl-2,3,5,6-tetramethylidenespiro[bicyclo[2.2.1]heptane-7,2′-oxirane] (3) was derived from 6,6-dimethylfulvene and maleic anhydride. Its reaction with 1 equiv. of ethylenetetracarbonitrile (TCNE) was not regioselective and gave a 1:1 mixture of the corresponding monoadducts 10 and 11. The rate constants of the Diels-Alder additions of 10 and 11 to TCNE were significantly smaller than that of the reaction 3 + TCNE. Monocomplexation of 3 with Fe2(CO)9 was highly exo-face selective giving a mixture of the corresponding monocomplexes 12(anti-exo) and 13(syn-exo). The latter were complexed with Fe2(CO)9 in a non-stereoselective fashion, giving mixtures of the dicomplexes 14(anti-exo, syn-endo), 15(anti-exo,syn-exo), and 16(anti-endo, syn-exo). Exchange of the CO ligands was a faster process for the endo-Fe(CO)3 moieties than for the exo-Fe(CO)3 moieties. Line-shape analysis of the 13C-NMR spectrum of 15 established that one of the exo-Fe(CO)3 groups in 15 rotates ca. 3 times as fast as the other Fe(CO)3 group at 40°. The structure of the anti-endo, syn-exo dicomplex 16 was determined by single-crystal X-ray diffraction studies.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700621
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    New Antifungal Chromenyl Ketones and their Pentacyclic Dimers from Hypericum revolutum VAHLPresented in part at the 34th Annual Congress on Medicinal Plant Research, Hamburg, FRG, 22-27 September, 1986. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1694-1702 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two new 2H-1-benzopyranyl ketones 1 and 2 and three new pyrano[3,2-c: 4,5,6-d′ e′]di[1]benzopyrandiyl diketones 3, 4a/4b, and 5 have been isolated from the leaves and twigs of Hypericum revolutum VAHL (Guttiferae). The structure of 3 (hyperevoline) was established by X-ray analysis as 1,1′-[1,13,13a,13b-tetrahydro-5,8,10-trihydroxy-2,2,6,9,13,13-hexamethyl-2H, 7aH-pyrano[3,2-c:4,5,6-d′e′]di[1]benzopyran-4, 11-diyl]bis[2-methyl-1-propanone]. The structures of the isolated compounds were established by spectroscopic (UV, IR, EI-MS, 1H- and 13C-NMR) and chemical (acetylation and acidic dimerization) methods.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700705
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Mammalian Alkaloids: Configurations of Optically Active Salsoline- and 3′,4′-Dideoxynorlaudanosoline-1-carboxylic AcidsSalsoline and norlaudanosoline are well known alkaloids, and these names will be used in the General Part (for systematic names, see Expert. Part). The systematic name for salsoline is 1-methyl-7-methoxy-1,2,3,4-tetrahydroisoquinolin-6-ol and that for norlaudanosoline, also named tetrahydropapaveroline, is 1-(3′,4′-dihydroxybenzyl)-1,2,3,4-tetrahydroisoquinoline-6,7-diol. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1721-1731 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of the optical isomers of (±)-methyl 6,7-dimethyl-3′,4′-dideoxynorlaudanosoline-1-carboxylate ((±)-2) was accomplished by reaction of (±)-2 with (+)-(R)-1-phenylethyl isocyanate, separation of the urea diastereoisomers (-)-4A and (+)-4B, and alcoholysis of the ureas in refluxing BuOH. Optically active isoquinoline-carboxylates 2A,B and hydantoins 8A,B isolated were characterized. The absolute configuration of the reaction products was established by X-ray analysis of the optically active hydantoin (+)-8A. Hydrolysis of the methyl isoquinolinecarboxylates 2A,B with 48% HBr soln. at reflux afforded the desired optically active 3′,4′-dideoxynorlaudanosoline-1-carboxylic acids 1A,B required for enzyme-inhibition studies. Details of the X-ray diffraction analysis of (+)-methyl salsoline-1-carboxylate hydrobromide ((+)-11A·HBr) prepared earlier are included. CD spectra of (+)-(S)-methyl 6,7-dimethyl-3′,4′-dideoxynorlaudanosoline-1-carboxylate hydrobromide ((+)-2A. HBr) and (-)-(R)-methyl salsoline-1-carboxylate hydrochloride ((-)-11B·HCl) confirmed the assignment of their (S)- and (R)-configurations, respectively.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700707
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Determination of the Quantum Yield of Intersystem Crossing of Rose Bengal (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1760-1773 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The quantum yield of intersystem crossing (Φisc) of a sensitizer is related to the quantum yield of singlet-oxygen production (Φ(1O2)) by the efficiency of the energy transfer (ϕet) and is an important parameter in the evaluation of potential applications of sensitized photo-oxidations. Using two different laser photolysis techniques, the energy-transfer method and the partial saturation method, Φisc of rose bengal has been determined in MeOH and in aqueous solutions. The results confirm that with Φisc(H2O) = 1.05(± 0.06) and Φisc(MeOH)=0.90(±0.08), the generally assumed relation Φisc · ϕet = Φ(1O2), with ϕet = 1, cannot be maintained any longer (Φ(1O2, H2O) = 0.75 and Φ(1O2, MeOH) = 0.76). During these experiments, a second intermediate has been observed which is produced from the triplet state of rose bengal and, stabilized in a anionic micellar solution, has been shown to be the radical cation of the sensitizer. The efficiency of the electron transfer has been evaluated from transient absorption and bleaching recordings, and it seems conclusive to attribute the results to the difference between Φisc and Φ(1O2).
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700712
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    ‘Face-to-Face’-Benzo-anellierte homologe Hypostrophene. Synthesen, Röntgenstrukturanalysen und PE-Spektren (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1816-1842 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ‘Face-to-Face’ Benzo-anellated Homologous Hypostrophenes. Syntheses, X-Ray-Structure Analyses and PE Spectra‘Face-to-face’ Benzo-anellated homologous hypostrophenes (series M), of interest as substrates for [6 + 6]-photocycloaddition reactions, have been synthesized. From X-ray structural analyses of 13b and 13c shortest C—C distances of 2.80(2.76)/2.71 Å and interorbital angles (ω) of 129° (128°)/130° between the benzene rings have been determined. The PE spectra are discussed in the context of transannular π,π interactions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700718
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Formation and Structure of the Phosphoranyl Radical Derived from 1,2-Phenylene Phosphorochloridate: a Solid-State ESR Study (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1897-1904 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The crystal structure of 1,2- phenylene phosphorochloridate has been determined. X-Ray irradiation of these crystals, at low temperature, leads to the formation of a radical exhibiting hyperfine structure with P and Cl nuclei. The corresponding ESR tensors are obtained, and they show that this radical is a phosphoranyl radical adopting a slightly distorded σ* structure. The same species could be produced in frozen solution, its hyperfine tensors are, then, more in accordance with a trigonal-bipyramid structure. The effects of the host matrix on the stabilization of the structure of phosphoranyl are investigated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700724
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Isolierung und Strukturaufklärung von 36 Diterpenoiden aus Trichomen von Plectranthus edulis (VATKE) T.T. AYE (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1911-1929 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Isolation and Structure Elucidation of 36 Diterpenoids from Leaf-Glands of Plectranthus edulis (VATKE) T.T. AYEAnalysis of the polar diterpenoids from the yellow glands of the title plant from Kenya and Abyssinia led to the identification of several novel abietanoids. Main compound is the known edulon A (40), a 5(4→3) abeo-abietane. Minor compounds include 6 different royleanones, 15 spirocoleons, 3 vinylogous quinones, 8 acylhydroquinones (as their 6,7-dioxo compounds or the tautomeric disophenols), 2 naphthaquinones (as the 1,10-seco-abietanoids), and deacetyledulon A. The known coleon-A-lactone (37) now has also been found in Plectranthus edulis. The intermediacy of the γ-enollactol 44, combined with a leaving group on C(3) is postulted to explain the biogenesis of the unusual 4H-5-oxaaceanthrylen skeleton of edulon A.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700726
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Synthesis of trans-10,11-Dihydro-10,11-dihydroxy-5H-dibenz[b,f]azepine-5-carboxamide, a Major Metabolite of Carbamazepine (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1955-1962 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stereoselectivity of the reduction of 5-carbamoyl-10,11-dihydro-11-oxo-5H-dibenz[b,f]azepine-10-yl acetate (6), prepared in two steps from 10,11-dihydro-10-oxo-5H-dibenz[b,f]azepine-5-carboxamide (4), has been studied. Among the reagents used, diisobutylaluminum hydride (DIBAH) was found to give the highest trans/cis diol ratio. This allowed the preparation of the important trans-diol metabolite 3 of carbamazepine (1).
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700730
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Are the known Δ2-cephems inactive as antibiotics because of an unfavourable steric orientation of their 4α-carboxylic group? Synthesis and biology of two Δ2-cephem-4β-carboxylic acids (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1967-1979 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two representatives of the yet unknown type of Δ2-cephem-4β-carboxylic acids were prepared. Contrarily to the prediction based on the activity model of Cohen, both acids proved inactive as antibiotics. Possible reasons for this discrepancy are briefly discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700732
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Isolierung von 10′-Apo-β-carotin-10′-ol und (3R)-10′-Apo-β-carotin-3,10′-diol (Galloxanthin) aus Rosenblüten. 5. Mitteilung über Rosenfarbstoffe1. bis 4. Mitt., s. [1-4]. (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 1988-1993 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Isolation of 10′-Apo-β-carotene-10′-ol and (3R)-10′-Apo-β-carotene-3,10′-diol (Galloxanthin) from Rose FlowersThe novel (all-E)-10′-apol-β-carotene-10′-ol (2) and (all-E,3R)-10′-apo-β-carotene-3,10′-diol (5) have been isolated from petals of one yellow species and various whitish or yellow blend varieties of rose cultivars. Each (all-E)-compound is accompanied by a (Z)-isomer, probably the (9Z)-isomer. Diol 5 proved to be identical with galloxanthin, an apo-10′-carotenol previously isolated from the retina of chicken.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700803
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Nucleotides. Part XXVI.Part XXV: [1].. A new synthesis of 9-(′-D-ribofuranosyl)uric acid and its 5′-monophosphateDedicated to Professor Morio Ikehara, Osaka University, Osaka, Japan (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 210-218 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Syntheses for 9-(β-D-ribofuranosyl)uric acid (16) and its 5′-monophosphate 14 have been achieved starting from guanosine and applying the 2-(p-nitrophenyl)ethyl group for protection of the aglycon moiety as well as the phosphate function. A more efficient and direct approach to 14 uses O6, O8-dibenzyl protection and phosphorylation by the Yoshikawa procedure. The various protected intermediates have been characterized by spectroscopic means and elemental analysis.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700126
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Erratum (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 271-271 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700131
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Intramolecular Cyclizations of Allenic Acylureas and -Amides (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 262-270 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Allenic acids are found to add to dicyclohexylcarbodiimide affording, in the presence of Et2NH, the 4H-1,3-oxazin-4-ones 5 via 4. Under neutral conditions, they add to diaryl- or pyridyl(cyclohexyl)carbodiimides and triphenylketene imine to give the corresponding tricyclo[5.2.2.01,5]undeca-4,8,10-trien-3-ones 7, 8, 9, and 12. The allenic phenyl ester 13a dimerises, on heating in a [2+2] head-to-head fashion, to 14 but fails to undergo intramolecular Diels-Alder cyclization, to 15.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700130
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Addition of Chiral Glycine, Methionine, and Vinylglycine Enolate Derivatives to Aldehydes and Ketones in the Preparation of Enantiomerically Pure α-Amino-β-Hydroxy Acids (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 237-261 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral enolates of imidazolidinones and oxazolidinones from the title amino acids react with carbonyl compounds to afford the corresponding alcohols in excellent yields (see Scheme 5). Furthermore, the addition to aldehydes proceeds with high diastereoselectivity to give, after acid hydrolysis, threo-α-amino-β-hydroxy acids of high enantiomeric purity. Some of the threo-α-amino-β-hydroxy acids prepared in this work are the proteinogenic (S)-threonine (26), the naturally occurring (S)-3-phenylserine (28), and (S)-3-hydroxyleucine (27) as well as the unnatural (S)-4,4,4-trifluorothreonine (30) and (S)-3-(4-pyridyl)serine (31). The N-methylamide of (2S,3R,4R,6E)-3-hydroxy-4-methyl-2-(methylamino)-6-octenoic acid (32), the unique amino acid in the immunosuppressive cyclosporine, was prepared by the new method. This report presents also information suggesting that both steric and stereoelectronic effects are responsible for the good stereoselectivities observed.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700129
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Mitteilungen - Communications (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 272-274 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700132
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Masthead (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987) 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700201
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Elektrochemische Oxidation von (S)-Äpfelsäure-Derivaten: ein Weg zu enantiomerenreinen alkylierten Malonaldehydsäure-estern (1987)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 70 (1987), S. 292-298 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electrochemical Oxidation of (S)-Malic-Acid Derivatives: a Route to Enantiomerically Pure Alkylmalonaldehydic EstersThe 3,3-dialkymalic-acid diesters, prepared by the previously described diastereoselective alkylations through dilithium alkoxide enolates, are saponified to the monoesters containing a free α-hydroxycarboxylic-acid moiety(Scheme 3). The monoesters are subjected to electrochemical oxidative decarboxylation in MeOH. If the intermediate monoacids are purified, the malonaldehydic esters (2-formy1-2-alkylcaroxylates) Obtained by this procedure are enantiomerically pure; they have the same structural features, i.e. two enantiotopic functionalized branches on the (persubstituted) stereogenic center, as the well known 3-hydroxy-2-methylpropanoic acid (‘Roche acid’) which was employed frequently as a starting material for the preparation of either enantiomer of various target molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19870700204
    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...