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  • Digitale Medien  (2.398)
  • 1985-1989  (2.398)
  • 1986  (1.210)
  • 1985  (1.188)
  • Organic Chemistry  (1.241)
  • Engineering General  (919)
  • pharmacokinetics  (238)
Datenquelle
Materialart
  • Digitale Medien  (2.398)
Erscheinungszeitraum
  • 1985-1989  (2.398)
Jahr
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  • 101
    Digitale Medien
    Digitale Medien
    The intra- and inter-subject variability of Nifedipine pharmacokinetics in young volunteers (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 57-60 
    Details
    ISSN: 1432-1041
    Schlagwort(e): nifedipine ; pharmacokinetics ; oral contraceptives ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Plasma concentrations of Nifedipine were measured following single oral doses of Nifedipine Slow Release (Adalat Retard) on three separate occasions to young, healthy volunteers of both sexes. Intra- and inter-subject variability were assessed by comparing the pharmacokinetic parameters, AUC, Cmax and T50%AUC. Interindividual variability was less than that observed in other studies with the betablockers, metoprolol and propranolol and there was no evidence of differences between the sexes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614196
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  • 102
    Digitale Medien
    Digitale Medien
    Pharmacokinetics and pharmacodynamics of the prostacyclin analogue iloprost in man (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 61-68 
    Details
    ISSN: 1432-1041
    Schlagwort(e): iloprost ; prostacyclin analogue ; pharmacokinetics ; platelet aggregation ; healthy male volunteers ; adverse effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Plasma levels of the prostacyclin analogue, iloprost, were measured by antibody/GC/MS in healthy male volunteers given 1 and 3 ng/kg per min i.v. for 45 min, and 1 µg/kg p.o. Following i.v. infusion, the steady-state plasma levels of iloprost were strictly dose-dependent (46±8 pg/ml and 135±24 pg/ml). The disposition was biphasic with half-lives of 3–4 min and 0.5 h. After oral administration, absorption of the drug was extremely rapid, the maximum plasma level of 251±32 pg/ml being achieved after 10±6 min. The bioavailability was 16±4%. Platelet aggregation induced by 2 µM ADP was reduced by 53% and 68% at the end of the two different infusions, and by 68% 15 min after p.o. administration. The ex-vivo inhibition of platelet aggregation by iloprost was not affected by preceding drug treatment. The cAMP content of platelets was increased by a factor of 2.5 at the end of the infusions and to a lesser extent 15 min after oral dosing. A slight increase in heart rate occurred during the infusion and within 30 min after oral administration; blood pressure was virtually unaffected. Except for transient side-effects (facial flush and headache) no adverse reactions were observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614197
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  • 103
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of methysergide and its metabolite methylergometrine in man (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 75-77 
    Details
    ISSN: 1432-1041
    Schlagwort(e): methysergide ; methylergometrine ; first-pass metabolism ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Five healthy men were given 1.0 mg methysergide maleate intravenously and 2.7 mg methysergide maleate orally in a cross-over study. The systemic availability of methysergide was only 13%, most probably due to a high degree of first-pass metabolism to methylergometrine. We also found evidence of extrahepatic clearance of methysergide. After oral administration the plasma concentrations of the metabolite were considerably higher than those of the parent drug and the area under the plasma concentration curve (AUC) for methylergometrine was more than ten times greater than for methysergide. Our findings may be relevant to the treatment of migraine if methylergometrine contributes to the effect of methysergide. Methylergometrine had a significantly longer elimination half-life than methysergide (223±43 min vs 62.0±8.3 min and 174±35 min vs 44.8±8.1 min in the oral and intravenous studies respectively).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614199
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  • 104
    Digitale Medien
    Digitale Medien
    Effect of cirrhosis and renal failure on the kinetics of clotiazepam (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 89-92 
    Details
    ISSN: 1432-1041
    Schlagwort(e): clotiazepam ; liver cirrhosis ; renal insufficiency ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The kinetics of a single 5-mg oral dose of the thienodiazepine clotiazepam was evaluated in a series of patients with biopsy-proven cirrhosis, and in patients with renal insufficiency requiring maintenance hemodialysis, compared to healthy matched controls. Clotiazepam volume of distribution (Vz) was significantly smaller in cirrhotic patients than in controls (1.83 vs 2.57 l/kg), and total clearance was likewise reduced (2.15 vs 3.15 ml/min/kg). Elimination half-life was similar between groups (10.0 vs. 10.2h). There were no significant differences between renal failure and control patients in clotiazepam Vz, oral clearance, or elimination half-life. Thus cirrhosis is associated with reduced clearance of clotiazepam, probably due to impairment of its microsomal oxidation. However clotiazepam disposition is not significantly altered in dialysis-dependent renal insufficiency patients.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614202
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  • 105
    Digitale Medien
    Digitale Medien
    The effects of age and chronic liver disease on the elimination of temazepam (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 93-97 
    Details
    ISSN: 1432-1041
    Schlagwort(e): temazepam ; liver disease ; elimination ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of the newer 1, 4 benzodiazepine temazepam were evaluated in 16 healthy subjects aged 18–92 years and in 15 cirrhotic patients, to ascertain the effect of ageing and liver disease. The data were analysed both by classic two compartment and by non-compartmental methods. The mean elimination half-life in the control subjects was 15.5 h, considerably longer than previous estimates. No correlation was found between age and pharmacokinetic parameters. The cirrhotic group showed no statistically significant difference in the pharmacokinetic parameters nor in the urinary recovery of the dose from the control group. Temazepam plasma protein binding was assessed in a second group of 9 cirrhotics of similar severity to the main group and in matched controls. When these binding data were applied to the mean clearance data, a modest although not statistically significant, reduction in free drug clearance was observed in the cirrhotic group. This study adds further support to the observation that drugs which undergo ether glucuronidation have normal elimination patterns in patients with liver disease. Temazepam may prove to be a useful hypnotic sedative in patients with liver disease.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614203
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  • 106
    Digitale Medien
    Digitale Medien
    Cirrhosis of the liver markedly impairs the elimination of mexiletine (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 83-88 
    Details
    ISSN: 1432-1041
    Schlagwort(e): mexiletine ; cirrhosis of the liver ; antiarrhythmic agents ; pharmacokinetics ; intravenous administration ; protein binding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary To study the effects of cirrhosis of the liver on the pharmacokinetics of mexiletine a single i.v. dose of 200 mg was administered to six cirrhotic patients and to six healthy controls. The distribution of mexiletine in both study groups was similar, as indicated by similar values of V1 and Vss, but it tended to occur more slowly in the cirrhotics. The plasma protein binding of mexiletine was unchanged in the patients with cirrhosis. The elimination of mexiletine was markedly retarded in the cirrhotics, as indicated by its lower total clearance (2.31 vs. 8.27 ml/kg/h,) lower total elimination rate constant (0.059 vs 0.353 h−1), and longer elimination half-life (28.7 vs 9.9 h). The antipyrine half-life was 38.3 h in the patients and 14.7 h in the controls. One healthy volunteer had a Morgagni-Stokes-Adams type of syncopal attack 5 min after administration of mexiletine due to disturbance of AV conduction induced by the drug. Thus, on a pharmacokinetic basis the loading dose of mexiletine need not be modified in cirrhotic patients, whereas the maintenance dosage should be reduced to one fourth — one third of the usual dose.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614201
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  • 107
    Digitale Medien
    Digitale Medien
    Ceftriaxone pharmacokinetics following multiple intramuscular dosing (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 109-112 
    Details
    ISSN: 1432-1041
    Schlagwort(e): ceftriaxone ; intramuscular ; pharmacokinetics ; steady-state
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The steady-state pharmacokinetics and tolerance of ceftriaxone after multiple i.m. doses of 0.5 and 1 g q12 h for 3.5 days were investigated in 12 healthy, adult volunteers. Ceftriaxone was rapidly absorbed after i.m. administration with mean peak times ranging from 1.3 to 1.9 h. Steady-state plasma concentrations were apparent after the third dose of both dosage regimens, with trough plasma concentrations of 24±6 and 39±8 µg/ml (mean±SD) after the 0.5 and 1 g q12 h regimens, respectively. Multiple i.m. administrations of ceftriaxone did not alter its elimination half-life; however, small increases were observed in the plasma clearance and volume of distribution at the 1-g regimen. These increases were attributed to the non-linear binding of ceftriaxone to human plasma proteins, and are therapeutically unimportant. Ceftriaxone was well tolerated and serious or lasting adverse reactions were not encountered in the study.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614206
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  • 108
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of dezocine, a new analgesic: Effect of dose and route of administration (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 121-123 
    Details
    ISSN: 1432-1041
    Schlagwort(e): dezocine ; opioid analgesics ; pharmacokinetics ; healthy volunteers ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of intravenous (IV) dezocine, and bioavailability of intramuscular (IM) and subcutaneous (SQ) dezocine, were evaluated in healthy male volunteers. Elimination half-life following 5, 10, and 20 mg IV doses averaged 2.6–2.8 h, and was independent of dose. Clearance decreased slightly, although significantly, with dose. After Deltoid IM injection, dezocine was rapidly absorbed (peak level: 0.6 h after dose), with bioavailability 97%. Thus dezocine has extensive distribution, high clearance and short half-life over a range of IV doses. It is rapidly and completely absorbed following IM or SQ administration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614208
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  • 109
    Digitale Medien
    Digitale Medien
    Comparison of single and multiple dose pharmacokinetics of theophylline using stable isotopes (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 113-120 
    Details
    ISSN: 1432-1041
    Schlagwort(e): theophylline ; pharmacokinetics ; stable isotopes ; diurnal variation ; single dose administration ; multiple dose administration ; systemic availability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Theophylline, enriched with the stable isotopes13C and15N, was administered intravenously in a dose of 10 mg to 8 healthy men following single (200 mg) and multiple (200 mg 8-hourly for 5 days) oral dose administration of aminophylline. Total plasma clearance, volume of distribution, and half-time determined from the intravenous data were similar, demonstrating that the pharmacokinetics of theophylline after chronic dosing can be predicted from the pharmacokinetics of a single dose. With chronic oral dosing, however, the mean trough concentration was 12% higher at 9 a.m. than at 5 p.m., the end of the dose interval (3.94±0.55 vs. 3.50±0.45 µg·ml−1). The AUC following oral dosing was 25% higher in the multiple dose study than in the single dose study. Simulation analysis suggested that these results could be explained by diurnal variation in the clearance or absorption rate or a combination of both. Thus, the systemic availability of theophylline measured during a single dosage interval after chronic oral dosing to steady state would be overestimated in comparison with that measured after a single oral dose.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614207
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  • 110
    Digitale Medien
    Digitale Medien
    Single dose oxazepam has no effect on acetaminophen clearance or metabolism (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 127-129 
    Details
    ISSN: 1432-1041
    Schlagwort(e): oxazepam ; acetaminophen clearance ; metabolite formation ; glucuronidation ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The metabolism of acetaminophen and oxazepam in humans is mainly dependent on the microsomal capacity for glucuronide conjugation. The clearance of acetaminophen and the formation of metabolites were evaluated in 7 patients before and during concomitant administration of oxazepam 30 mg. The subjects received a single 500 mg dose of acetaminophen i.v. and concentrations in plasma were measured for 360 minutes and in urine for 24 h in order to estimate the production of metabolites. The single therapeutic dose of oxazepam had no effect on the clearance of acetaminophen or on formation of its metabolites.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614210
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  • 111
    Digitale Medien
    Digitale Medien
    Treatment of essential hypertension with felodipine in combination with a diuretic (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 133-139 
    Details
    ISSN: 1432-1041
    Schlagwort(e): felodipine ; hydrochlorothiazide ; essential hypertension ; calcium antagonist ; pharmacokinetics ; plasma noradrenaline ; adverse effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary In a double-blind cross-over study, the effect on blood pressure (BP), heart rate (HR) and plasma noradrenaline concentration (pNA) of placebo or felodipine given in addition to hydrochlorothiazide was studied in 12 male patients with essential hypertension, not satisfactorily controlled with the diuretic alone. The first dose of felodipine decreased BP and increased HR for about 6 h. After 4 weeks of treatment with felodipine, BP was reduced for 24 h, whereas HR was only transiently increased. The elimination half-life of felodipine was about 23 h. The plasma noradrenaline concentration increased after felodipine and serum uric acid decreased. Side-effects were few and usually mild.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00614290
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  • 112
    Digitale Medien
    Digitale Medien
    Pharmacokinetics and pharmacodynamics in man of the dopamine antagonist ergot derivative, bromerguride (1986)
    Springer
    European journal of clinical pharmacology 31 (1986), S. 165-168 
    Details
    ISSN: 1432-1041
    Schlagwort(e): bromerguride ; dopamine antagonist ; pharmacokinetics ; pharmacodynamics ; prolactin level ; side-effects ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The plasma levels and urinary excretion of the dopamine antagonist, bromerguride, were measured by radioimmunoassay in healthy male volunteers given 50 µg i.v. and oral doses of 1 and 2 mg. Plasma prolactin was also measured by radioimmunoassay. Following i.v. injection, the concentration of bromerguride declined biphasically, with half-lives of 7 min and 1.2h. The total clearance was 32 ml·min−1·kg−1 and the apparent volume of distribution was 3.6 l/kg. The bioavailability of oral bromerguride was 29% after 1 mg and 25% after 2 mg. The drug was almost totally metabolized and less than 0.05% of the dose was excreted in urine in 24 h after oral administration. Plasma prolactin levels were increased in a dose-dependent manner for about 8 h. Side-effects were minimal, mainly being tiredness and headache in some of the volunteers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00606653
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  • 113
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of tenoxicam in patients with impaired renal function (1986)
    Springer
    European journal of clinical pharmacology 29 (1986), S. 697-701 
    Details
    ISSN: 1432-1041
    Schlagwort(e): tenoxicam ; renal insufficiency ; non-steroidal antiinflammatory agents ; protein binding ; metabolism ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of tenoxicam after a single oral dose of 20 mg has been studied in 12 patients with various degrees of decreased renal function. Unchanged tenoxicam and its 5′OH-metabolite in plasma and urine were determined by HPLC. The mean areas under the plasma concentration-time curve (138±53 µg/ml·h) and terminal half-lives in patients with impaired renal function did not differ from values previously reported in normal volunteers, nor did the peak concentration of tenoxicam. The half-life of 5′OH-tenoxicam and unchanged tenoxicam where the same. The urinary excretion of 5′OH-tenoxicam fell with decreasing renal function. Thus no dosage adjustment should be necessary and the usual daily dose of tenoxicam may be administered once daily also to patients with renal failure.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00615961
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  • 114
    Digitale Medien
    Digitale Medien
    The pharmacokinetics after intravenous and oral administration in man of theα 2-adrenoreceptor antagonist idazoxan (RX781094) (1986)
    Springer
    European journal of clinical pharmacology 29 (1986), S. 743-745 
    Details
    ISSN: 1432-1041
    Schlagwort(e): idazoxan ; pharmacokinetics ; alpha 2-adrenoceptor antagonist ; healthy volunteers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A high performance liquid chromatographic method was developed for the quantitative determination of idazoxan in plasma. The assay was used to study the disposition of the drug after intravenous infusion and oral administration to five normal subjects. After i.v. administration the kinetics could be described by a two compartment model with a mean elimination half life of 4.20 h. The mean calculated volume of distribution during the elimination phase was 3.20 l/kg−1 and the mean plasma clearance was 824 ml min−1. After oral administration a lag period before onset of absorption was observed in all five volunteers, the plasma levels declining monoexponentially from the peak concentration with a mean elimination half life of 5.58 h. The absolute availability varied between 26% and 41% with a mean value of 34%. Invitro measurements produced a blood/plasma ratio of 1.3 for idazoxan.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00615972
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  • 115
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of temazepam in geriatric patients (1986)
    Springer
    European journal of clinical pharmacology 30 (1986), S. 745-747 
    Details
    ISSN: 1432-1041
    Schlagwort(e): temazepam ; pharmacokinetics ; geriatric patients ; benzodiazepines
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary A single dose of temazepam 10 mg, as a solution in soft gelatin capsules, was given to 10 fasting geriatric in-patients (mean age 83 years) in a stable clinical condition. The mean peak plasma concentration was 306 ng/ml, with a median time of 0.75 h to peak concentration. Temazepam was eliminated from plasma in a biexponential manner, with a distribution phase (mean t1/2α=0.7 h) predominating for 3 h. The drug had a mean elimination half-life of 8.7 h. In a chronic study, in which temazepam 10 mg p.o. was given nightly to 13 patients, the plasma concentrations on Days 3, 5, 8, 12 and 15 were not significantly different from each other, showing rapid attainment of steady state levels and the lack of drug accumulation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00608229
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  • 116
    Digitale Medien
    Digitale Medien
    5-Aminosalicylic acid in patients with an ileo-rectal anastomosis (1986)
    Springer
    European journal of clinical pharmacology 31 (1986), S. 23-26 
    Details
    ISSN: 1432-1041
    Schlagwort(e): sulphasalazine ; Pentasa ; slow release preparation ; 5-aminosalicylic acid ; ileo-rectal anastomosis ; ulcerative colitis ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics of 5-aminosalicylic acid (5-ASA) from sulphasalazine (SASP) and the slow-release 5-ASA preparation Pentasa was investigated in a cross-over study in 9 otherwise healthy patients with an ileo-rectal anastomosis. The 24-hour recoveries of the drugs were 90.5% and 84.7%, respectively. The median release of 5-ASA from SASP was 50% and from Pentasa 75%. Equal amounts of 5-ASA (18.0% vs 17.9%) were found in the faeces, and a significantly larger amount (4.4% vs 28.9%) of the metaboliteN-acetyl-5-aminosalicylic acid (ac-5-ASA) was found in faeces following Pentasa. A larger amount of 5-ASA was absorbed and subsequently excreted in the urine, mainly as the metabolite (2.5% vs 20.5%) from Pentasa. This confirms previous results in ileostomized patients treated with Pentasa. The present findings also demonstrate that bacterial azo-reduction of SASP in patients with ileorectal anastomosis may be an adequate way to deliver 5-ASA in this type of patient. Both treatments may be used in these patients during a flare up of ulcerative colitis, but randomized studies are needed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00870980
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  • 117
    Digitale Medien
    Digitale Medien
    Pharmacokinetics and metabolism of quinidine in extensive and poor metabolisers of sparteine (1986)
    Springer
    European journal of clinical pharmacology 31 (1986), S. 69-72 
    Details
    ISSN: 1432-1041
    Schlagwort(e): quinidine ; sparteine ; pharmacokinetics ; drug oxidation ; polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The pharmacokinetics and metabolism of quinidine were investigated in extensive and poor metabolisers of sparteine. No differences in plasma clearance, terminal half life, volume of distribution or cumulative urinary excretion of quinidine, 3-hydroxyquinidine and quinidine-N-oxide were observed between phenotypes. Thus, it is unlikely that quinidine metabolism is controlled by the sparteine/debrisoquine gene locus.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00870989
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  • 118
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of intravenous and intraperitoneal ceftriaxone in chronic ambulatory peritoneal dialysis (1986)
    Springer
    European journal of clinical pharmacology 31 (1986), S. 479-483 
    Details
    ISSN: 1432-1041
    Schlagwort(e): ceftriaxone ; dialysis ; continous ambulatory peritoneal dialysis ; pharmacokinetics ; intraperitoneal administration ; intravenous administration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The kinetics of ceftriaxone was investigated in 8 patients without infection, who were receiving continuous ambulatory peritoneal dialysis (CAPD). Ceftriaxone 1 g was injected i.v. and 1 g was given intraperitoneally in the CAPD fluid during a 4-h dwell time. Ceftriaxone was assayed by HPLC. After intravenous administration, the kinetic parameters of ceftriaxone were: plasma t1/2, 12.3 h, total plasma clearance, 14.0 ml/min, volume of distribution at steady state 0.18 l/kg, and peritoneal clearance 0.59 ml/min. Over 72 hours only 5.5% of the dose was eliminated by the peritoneal route. After intraperitoneal administration, ceftriaxone rapidly appeared in serum; the absorption t1/2 was 1.1 h and the mean peak concentration was 38.8 µg/ml. The absorption of ceftriaxone from the peritoneal space was 39%. A single 1.0 g IP dose led to serum and dialysate concentrations of ceftriaxone above the minimum inhibitory concentration for susceptible pathogens for 24 hours.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00613528
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  • 119
    Digitale Medien
    Digitale Medien
    Diuretic activity, safety and pharmacokinetics of torasemide during chronic treatment in normal subjects (1986)
    Springer
    European journal of clinical pharmacology 31 (1986), S. 1-7 
    Details
    ISSN: 1432-1041
    Schlagwort(e): torasemide ; diuretic activity ; pharmacokinetics ; healthy subjects ; side-effects
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Torasemide 40 mg/day p.o. was administered for 21 days to 8 healthy volunteers to investigate its pharmacodynamics, pharmacokinetics and safety on chronic administration. It induced a highly significant initial increase in 24-h urinary volume and 24-h excretion of sodium and chloride, but its affect diminished after the first days. On Days 0, 1, 10 and 21 the experiement was divided in 3 clearance phases, extending from 0 to 2 h, 2 to 6 h and 6 to 24 h after dosing. The fractional excretion of sodium, chloride, potassium, calcium, magnesium and inorganic phosphates peaked during the first 2 h and returned almost to the control value during the following two clearance phases. The phase-dependent changes were significant for all electrolytes, except for potassium and inorganic phosphate. Plasma electrolyte levels remained constant throughout the study, except for a small decrease in chloride and potassium and for an increase in calcium and magnesium. Fasting blood glucose and glucose tolerance test were unaffected. A small but significant decrease in LDL-cholesterol was observed on Day 10. Other plasma lipid components showed minor changes. Plasma uric acid levels were moderately increased. There was no significant change of the creatinine clearance. Body weight fell significantly (by about 2 kg) during the study. Tonal audiometry was normal before and after the study. There was no significant difference between the plasma levels of torasemide on Days 1, 10 and 21, nor between its elimination half-life on Days 1 and 21. Side-effects consisted mainly of fatigue and low-back pain on days of intense diuresis. There were no toxic symptoms. ECG recordings and blood pressure remained within normal limits.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00541460
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  • 120
    Digitale Medien
    Digitale Medien
    Comparative analysis of the pharmacokinetics of unsubstituted N1-derivatives of 1,4-benzodiazepine (1986)
    Springer
    Bulletin of experimental biology and medicine 101 (1986), S. 206-209 
    Details
    ISSN: 1573-8221
    Schlagwort(e): 1,4-benzodiazepines ; pharmacokinetics ; plasma/brain concentration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00836121
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  • 121
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of a water-soluble antioxidant of 3-hydroxypyridine type (1986)
    Springer
    Bulletin of experimental biology and medicine 101 (1986), S. 333-335 
    Details
    ISSN: 1573-8221
    Schlagwort(e): antioxidant ; 3-hydroxypyridines ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00835938
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  • 122
    Digitale Medien
    Digitale Medien
    Radioimmune and radioreceptor study of the pharmacokinetics of the enkephalin analog dalargin in man (1986)
    Springer
    Bulletin of experimental biology and medicine 101 (1986), S. 783-785 
    Details
    ISSN: 1573-8221
    Schlagwort(e): dalargin ; pharmacokinetics ; enkephalins
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00839605
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  • 123
    Digitale Medien
    Digitale Medien
    A dispersion model of hepatic elimination: 2. Steady-state considerations-influence of hepatic blood flow, binding within blood, and hepatocellular enzyme activity (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 261-288 
    Details
    ISSN: 1573-8744
    Schlagwort(e): hepatic elimination ; hepatic clearance ; availability ; intrinsic clearance ; pharmacokinetics ; dispersion model ; well-stirred model ; tube model ; distributed model ; blood flow ; binding within blood ; hepatocellular enzyme activity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The dispersion model of hepatic elimination is based on the distribution of residence times of blood elements within the liver. The model has two asymptotic solutions corresponding to the “wellstirred” model (complete mixing of blood elements) and the “parallel-tube” model (no variation in residence times of blood elements). The steady-state form of the dispersion model relevant to pharmacokinetic analysis is developed and explored with respect to changes in blood flow, in binding within blood, and in hepatocellular enzyme activity. Literature data are used to evaluate discrepancies among the predictions of the dispersion, well-stirred, and tube models. It is concluded that the dispersion model is consistent-with the data. The limitations of steady-state perfusion experiments to estimate the residence time distribution of blood elements within the liver are considered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01106707
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  • 124
    Digitale Medien
    Digitale Medien
    In vivo interaction of the enantiomers of disopyramide in human subjects (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 335-356 
    Details
    ISSN: 1573-8744
    Schlagwort(e): disopyramide ; pharmacokinetics ; stereoisomers ; antiarrhythmic agents
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Disopyramide, an antiarrhythmic agent, is marketed as a racemic mixture of two enantiomers. The racemic drug has unusual pharmacokinetic properties because of its concentration-dependent binding to plasma proteins in the therapeutic plasma concentration range. This study examined, in healthy subjects, the individual pharmacokinetic properties of both total and unbound d-and ldisopyramide in plasma after intravenous administration of each enantiomer separately (1.5mg/kg).Also investigated is the pharmacokinetics of total d-and l-disopyramide in plasma after intravenous administration of a pseudoracemate. Both d-and l-disopyramide are found to exhibit concentration-dependent binding to plasma proteins, with d-disopyramide being more avidly bound at lower concentrations. The stereoselective, concentration-dependent binding to plasma proteins resulted in distinct pharmacokinetic properties when the enantiomers were given together as the pseudoracemate. d-Disopyramide had a lower plasma clearance and renal clearance, a longer half-life, and a smaller apparent volume of distribution than l-disopyramide. However, when the enantiomers were administered separately, there were no differences in the clearance, renal clearance, and volume of distribution between enantiomers calculated from either total or unbound drug concentrations. The results reveal an important pharmacokinetic interaction between the enantiomers of disopyramide when given as a racemic mixture, which may be dose-dependent and is not apparent upon administration of the enantiomers separately.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059195
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  • 125
    Digitale Medien
    Digitale Medien
    The impact of neglecting nonlinear plasma-protein binding on disopyramide bioavailability studies (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 365-379 
    Details
    ISSN: 1573-8744
    Schlagwort(e): disopyramide ; bioavailability ; protein binding ; nonlinear ; sustained release ; pharmacokinetics ; ultrafiltration ; immunoassay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Disopyramide has nonlinear protein binding and thus the relationship between the extent of its bioavailability and AUC,the area under the plasma concentration-time curve, is (1) nonlinear and (2) absorption rate-dependent. The unbound species follows linear pharmacokinetics. A solution of disopyramide, the innovator's product, and two generic formulations were found to be statistically indistinguishable in their bioavailability of disopyramide, whether comparison was based upon AUCor area under the plasma unbound concentration-time curve (AUCu).The AUCand AUCugave similar results because of truly similar bioavailability, coupled with sufficiently similar release rates, among the four preparations chosen for study. The concentration dependence of disopyramide protein binding and the time course of unbound plasma concentrations were fit by models which then allowed prediction of AUCunder various biopharmaceutical scenarios. Nonlinear binding of disopyramide to plasma proteins renders AUCan insensitive parameter for the discrimination of products with different extents of bioavailability; immediate release products allowing bioavailabilities of 75 or 125% relative to the solution can generate AUCs86 and 112%, respectively, of that from the solution. Nonlinear binding, furthermore, leads to a tendency for AUC tooverestimate the bioavailability of slower release products in single-dose studies; if AUCwere the index of bioavailability, products permitting the same bioavailability as the solution but releasing over 12 hr could appear to allow 114% relative bioavailability. Moreover, in some situations the bias arising from the insensitivity of AUCto product differences can be reinforced by the dependence of AUCon release rate; an apparent relative bioavailability of 80% can be achieved by a 12-hr release product allowing a true relative bioavailability of a mere 58%. While multiple-dose studies appear largely to avoid the tendency to overestimate low bioavailability in slow-release products, in these studies AUCappears to be even more insensitive in resolving discrepancies between products. Assay technology now available makes AUCua feasible and more reliable index of bioavailability than AUCwhen plasma protein binding of drugs is nonlinear.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059197
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  • 126
    Digitale Medien
    Digitale Medien
    On the pharmacokinetics of 16-acetyl-gitoxin and its bioavailability from pengitoxin-containing tablet formulations (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 357-364 
    Details
    ISSN: 1573-8744
    Schlagwort(e): 16-acetyi-gitoxin ; pengitoxin ; pharmacokinetics ; bioavailability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In six volunteers the pharmacokinetics of 16-acetyI-gitoxin (16AG, 0.5mg) administered intravenously (A1) and as an oral solution (A2) and of pengitoxin (PAG, 0.6 mg) administered intravenously (A3) was evaluated. In six volunteers the bioavailability of 16AG from two PAG tablet formulations (1.2 mg) (B2, B3) was measured by comparison with the absorption after administration of a pengitoxin solution (1.2mg) (B1). In both studies the test was performed using a crossover design. After a single i.v. injection of equimolar doses, 16AG and PAG showed similar mean kinetic parameters: t 1/2 =51.6hr (16AG) and 60.8 hr (PAG), CL=11.7ml min−1 (16AG) and 12.7ml min−1 (PAG), CLR=4.1 ml min−1 (16AG) and 4.2ml min−1 (PAG). The 16AG was absorbed from solution with a mean half-life of 0.2hr to an extent of 98.6%. The mean urinary excretion /Ae(0, 4)/ of 16AG amounted to 24.6% (A1), 20.8% (A2) and 28.1% (A3). On the basis of AUCvalues, the mean bioavailability of PAG from either tablet formulation amounted to 79.6% (B2) and 89.6% (B3). The pharmacokinetic parameters of 16AG (PAG) are closer to those of digitoxin than those of digoxin. In general, 16AG is characterized as a digitoxin with a digoxin-like elimination half-life.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059196
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  • 127
    Digitale Medien
    Digitale Medien
    Pharmacokinetics of isosorbide dinitrate and its mononitrate metabolites after intravenous infusion (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 1-17 
    Details
    ISSN: 1573-8744
    Schlagwort(e): isosorbide dinitratekw]isosorbide 2-mononitrate ; isosorbide 5-mononitrate ; metabolism ; pharmacokinetics ; modeling ; simultaneous estimation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Plasma concentrations of isosorbide dinitrate (ISDN) and its two active metabolites 2-isosorbide mononitrate (2-ISMN) and 5-isosorbide mononitrate (5-ISMN) have been measured during and for 6 hr after intravenous infusion at a rate of 2.5mg/hr during 1.75 hr in six cardiac patients, by a capillary gas chromatographic method. Data were analyzed by simultaneous modeling of the observed kinetics of the three compounds. Two or three phases were detected on the postinfusion ISDN concentration-time curves. ISDN concentrations declined with a mean terminal half-life of 2.81 hr±0.7 SD. The mean systemic clearance of ISDN (2.9 L/min ±0.7 SD) and its mean total volume of distribution (259 L +- 48 SD) were relatively high. Plasma 5-ISMN concentrations were 5- to 6-fold greater than those of 2-ISMN during the whole observation period. Maximum levels of 2-ISMN (6.7 ng/ml ± 0.9 SD) and of 5-ISMN (27 ng/ml ± 6 SD) occurred within a few minutes after the end of infusion. The mean half-lives of 2-ISMN (1.59 hr± 0.19 SD) and of 5-ISMN (3.78 hr± 0.79 SD) estimated by the model were smaller than those calculated by a model-independent method (2.95 hr± 0.41 SD and 5.98 hr± 2.22, respectively), but were in good agreement with those reported in the literature following separate administration of both metabolites to man. This study shows how such modeling can distinguish between metabolite formation and elimination processes and allow the determination of metabolite half-lives after administration of the precursor drug.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059280
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  • 128
    Digitale Medien
    Digitale Medien
    Physiological pharmacokinetic modeling ofcis-dichlorodiammineplatinum(II) (DDP) in several species (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 131-155 
    Details
    ISSN: 1573-8744
    Schlagwort(e): pharmacokinetics ; physiological model ; cisplatin ; DDP ; cis-dichlorodiammineplatinum(II)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A physiological pharmacokinetic analysis ofcis-dichlorodiammineplatinum(II) (DDP) is presented for the rabbit, dog, and human. The results are compared to a previous analysis for the rat. DDP binds irreversibly to low-molecular weight nucleophiles and macromolecules to form mobile and fixed metabolites at rates which are tissue-specific. The rate constant for the formation of fixed metabolite in plasma, determined by in vitro incubation, ranges from 0.004 to 0.008 min−1.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01065258
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  • 129
    Digitale Medien
    Digitale Medien
    Receptor-mediated model relating anticonvulsant effect to brain levels of camazepam in the presence of its active metabolites (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 309-321 
    Details
    ISSN: 1573-8744
    Schlagwort(e): camazepam ; temazepam ; oxazepam ; pharmacokinetics ; anticonvulsant effect ; radioreceptor assay ; rat ; mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In a displacement test using3H-diazepam as a radioligand, the in vitro affinities of metabolites of camazepam (CZ) for the benzodiazepine receptors were 1–50 times more potent than that of CZ. In contrast, only three metabolites (temazepam, oxazepam, and hydroxy CZ), as well as CZ itself, exhibited an in vivo affinity parallel to their ability to protect against pentylenetetrazole-induced clonic convulsion in rats. In addition, CZ and these active metabolites displaced the radioligand from their receptor sites in a concentration-dependent saturable manner, indicating the competitive bimolecular interaction of these molecules with their receptors. The percent anticonvulsant effect was a nonlinear, single-valued function of the in vivo percent displacement of specific3H-diazepam binding, independent of these displacers after i.v. dosing; this relationship could be approximated by the Hill equation. On the basis of these findings, a receptor-mediated model, including the Langmuir equation to describe the receptor binding-brain concentration relationship and the Hill equation to accommodate the anticonvulsant effect-receptor binding relationship, was constructed. This model was found to adequately relate the time course values of anticonvulsant effect and of brain levels of CZ and its active metabolites after oral administration. These results demonstrate that CZ and its active metabolites exert anticonvulsant effect by competitive binding to the benzodiazepine receptors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01106709
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  • 130
    Digitale Medien
    Digitale Medien
    Effect of caffeine on ceftriaxone disposition and plasma protein binding in the rat (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 397-408 
    Details
    ISSN: 1573-8744
    Schlagwort(e): caffeine ; ceftriaxone ; plasma ; tissue ; pharmacokinetics ; compartment model ; protein binding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Previous studies have shown that caffeine can affect drug kinetics by altering drug binding to plasma protein, drug absorption, or drug distribution. In this study, the effect of caffeine on the in vivoprotein binding and the disposition of ceftriaxone (a highly protein-bound cephalosporin) were investigated in the rat. Ceftriaxone 100mg/kg and caffeine 20mg/kg were i.v. injected via the tail vein and ceftriaxone in plasma, plasma filtrate, urine, feces, and tissues (brain, heart, kidney, liver, gut, lung, and muscle) was assayed by HPLC with UV detection. The fraction of free ceftriaxone in plasma ranged from 5.6 to 32.8% of total ceftriaxone (3–347 μg/ml) without caffeine and showed no alteration by caffeine. The total amount of ceftriaxone excreted in urine and feces was increased significantly (p〈0.05)from 13.1±1.8mg (mean±SD, 54.6% of total) to 15.3 ±1.1 mg (63.8% of total) by caffeine coadministration. The terminal half-life of ceftriaxone in plasma was shortened from 59 to 47 min, and the area under the plasma drug concentration-time curve (AUC)was reduced from 612 to 516 μg hr/ml Although the peak drug concentrations and the times of peak concentration of ceftriaxone in tissues were not altered by caffeine administration, the elimination of ceftriaxone was increased, as indicated by generally shorter half-lives (decreases ranged from 17.5% in liver to 34.2% in brain) and lower AUCvalues (from 9.0% in heart to 54.5% in brain). These results suggest that caffeine does not alter the protein binding of ceftriaxone, but enhances the elimination of ceftriaxone in the rat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059199
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  • 131
    Digitale Medien
    Digitale Medien
    Drug pharmacokinetics and the carbon dioxide breath test (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 29-49 
    Details
    ISSN: 1573-8744
    Schlagwort(e): carbon dioxide ; breath test ; pharmacokinetics ; metabolite ; extraction ratio ; aminopyrine ; caffeine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The interrelationship of the pharmacokinetics of a drug and the expiration of carbon dioxide formed as a metabolite have been studied. The pharmacokinetic characteristics of the drug that affect the usefulness of the carbon dioxide excretion as a measure of liver function were examined by means of computer simulations. The parent drug extraction ratio, fraction demethylated, volume of distribution, and absorption rate of an oral dosage form all contribute to the carbon dioxide breath test result. A drug that would be a useful substrate when the carbon dioxide breath test is used as a probe for changes in liver function should be at least 50% metabolized by demethylation, have a hepatic extraction ratio of 0.2–0.5, and be administered in a form that is rapidly absorbed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059282
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  • 132
    Digitale Medien
    Digitale Medien
    Effects of the rate and composition of fluid replacement on the pharmacokinetics and pharmacodynamics of intravenous furosemide (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 495-509 
    Details
    ISSN: 1573-8744
    Schlagwort(e): furosemide ; pharmacokinetics ; pharmacodynamics ; fluid replacement
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Effects of differences in the rate and composition of intravenous fluid replacement for urine loss on the pharmacokinetics and pharmacodynamics of furosemide were evaluated using the dog as a model animal. Each of six dogs received 8-hr constant intravenous infusion of 20 mg (15 mg used in one dog) of furosemide with 0% replacement (treatment I), 50% replacement (treatment II), and 100% replacement (treatment III) with lactated Ringer's solution, as well as with 100% replacement with 5% dextrose in water (treatment IV). Most pharmacokinetic parameters, such as plasma clearance, steady-state volume of distribution, mean residence time, and terminal half-life, were essentially the same in all four treatments. Renal clearances and urinary excretion rates of the drug in treatments II–IVwere essentially the same, but about 20% higher than those in treatment I.In spite of the similarities in kinetic properties, diuretic and/or natriuretic effects from furosemide were markedly different among the four treatments. For example, mean 10-hr urine outputs were 646, 1046, 3156, and 1976 ml and mean 10-hr sodium excretions were 87.0, 142, 383, and 97.2 mmole for treatments I–IV,respectively. Except for treatment III,diuresis and/or natriuresis were found to be time-dependent, generally decreasing with time until reaching a low plateau during later hours of infusion. The present findings also showed that (1)no fluid replacement and 100% replacement with 5% dextrose solution both produced the same degree of severe acute tolerance in natriuresis, indicating the insignificance of water compensation in tolerance development; (2)in treatment II,where neutral sodium balance was achieved, the development of acute tolerance in diuresis and natriuresis can mainly be attributed to negative water balance under this special condition; (3)at steady state the hourly diuresis and natriuresis could differ up to about ten times between treatments. Some implications for the kinetic/dynamic relationship or modeling, in the clinical use, and in the bioequivalence evaluation of dosage forms are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059657
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  • 133
    Digitale Medien
    Digitale Medien
    Amiodarone pharmacokinetics. I. Acute dose-dependent disposition studies in rats (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 601-613 
    Details
    ISSN: 1573-8744
    Schlagwort(e): amiodarone ; pharmacokinetics ; dose-dependent ; rats
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Single intravenous bolus doses of amiodarone hydrochloride of 30, 60, 90 and 120 mg/kg were administered to male Sprague-Dawley rats to determine the effects of dose on amiodarone pharmacokinetics. Serial blood samples and total urine were collected over 48 hr and assayed for amiodarone and desethylamiodarone by HPLC. The blood amiodarone concentration-time curves for the four doses were best described by a triexponential equation with terminal half-lives (t 1/2γ ) ranging from 17 to 20 hr. Over the dose range studied, no changes in γ, t 1/2γ , or central compartment volume (Vc=1.2–1.4 L/kg) were observed. On the other hand, reductions in amiodarone clearance (CL and steady-state volume of distribution (V ss of 44% (17.7 to 10.0 ml/min per kg) and 50% (16.4 to 8.2 L/kg), respectively, were noted as the dose of amiodarone increased. The conversion of amiodarone to desethylamiodarone (fm was dose-independent and amounted to approximately 10% of each amiodarone dose. No amiodarone or desethylamiodarone was detected in the urine of any of the treated animals. The blood-to-plasma concentration ratio of amiodarone was concentration-independent and therefore did not account for the dose-dependent changes in Vss and CL observed. The data suggested that the dose-dependent changes noted were due to an alteration in the volume (s) of the peripheral tissue compartment(s).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01067966
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  • 134
    Digitale Medien
    Digitale Medien
    Analysis of pethidine disposition in the pregnant rat by means of a physiological flow model (1986)
    Springer
    Journal of pharmacokinetics and pharmacodynamics 14 (1986), S. 381-395 
    Details
    ISSN: 1573-8744
    Schlagwort(e): pethidine ; rat ; physiological flow model ; pharmacokinetics ; pregnancy ; scale up ; opiates, GC-MS analytical method ; simulations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The disposition of pethidine (meperidine) in the pregnant rat is described by means of a physiological flow model. The model includes arterial and venous blood, brain, fat, fetal, hepatic, intestinal, muscular, pulmonar, and renal tissues. The concentration-time profiles of pethidine calculated by the model are consistent with experimental data, except for the brain and renal tissues, where the model predicts initially higher concentrations. Simulations are carried out to further explore the contribution from different organs on the kinetics in blood and tissues. The tissue-to-blood partition coefficients vary over a range from 5 to 316, where fat has the lowest and liver the highest after a correction is made due to hepatic extraction. Rapid uptake occurs into highly perfused organs such as brain, kidneys, liver, and lungs, followed by fetus, intestines, muscle, and fat. Data indicate no marked membrane resistance to pethidine of the investigated organs, except for fetal tissues, but rather a perfusion-limited uptake. Simulations suggest that muscles and adipose tissue play an important role in the rat, becoming the major reservoir of drug during the intermediate and terminal elimination phase, respectively. Volume of distribution and the biological half-life agree with reported findings. Pethidine is subject to a high systemic blood clearance, which exceeds the total hepatic blood flow in the rat. No degradation of pethidine is found in blood, and therefore a pulmonary expression for pethidine clearance is added as a potential source of pethidine elimination. The elimination of pethidine after a single i.v. bolus dose is found to be dependent on simulated changes in cardiac output and hepatic blood flow. A simulation is performed with the scaled model to mimic the human concentration-time profiles in maternal blood and brain tissues and fetal tissue during repetitive doses of pethidine.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01059198
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  • 135
    Digitale Medien
    Digitale Medien
    Saturable Processes Affecting Renal Clearance of Cefixime in Dogs (1986)
    Springer
    Pharmaceutical research 3 (1986), S. 150-155 
    Details
    ISSN: 1573-904X
    Schlagwort(e): renal clearance ; cephalosporin ; cefixime ; tubular reabsorption ; saturable protein binding ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The pharmacokinetics of cefixime, a new orally active cephalosporin, was studied after an intravenous dose of 50 mg/kg to four beagle dogs. Cefixime was shown to exhibit concentration dependent serum protein binding and saturable tubular reabsorption. The drug was excreted mainly in the urine, the net result of glomerular filtration and saturable tubular reabsorption. The experimental results were analyzed by model independent pharmacokinetic equations and with theoretical models describing renal clearance. Modification of the models, based on observed data, was proposed. The experimental methods employed and the pharmacokinetic approach offered in this study can be applied to drugs that exhibit concentration dependent protein binding and saturable renal elimination processes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1016309923717
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  • 136
    Digitale Medien
    Digitale Medien
    The Effect of Amiodarone on Theophylline Pharmacokinetics in the Rat (1986)
    Springer
    Pharmaceutical research 3 (1986), S. 167-169 
    Details
    ISSN: 1573-904X
    Schlagwort(e): amiodarone ; theophylline ; pharmacokinetics ; drug interaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Amiodarone is an investigational antiarrhythmic agent which has been implicated in reducing the activity of the hepatic mixed-function oxidase system. To evaluate this effect further, two groups of six male Sprague–Dawley rats each received theophylline (6 mg/kg, iv) preceded by either normal saline or amiodarone HC1 (100 mg/kg, iv). Blood samples were obtained serially for a period of 6 hr and the sera were assayed for theophylline by high-pressure liquid chromatography (HPLC). In rats pretreated with amiodarone, a significant 45% reduction in the mean (± SD) systemic clearance [0.057 (0.010) vs 0.031 (0.004) liter/hr/kg, P 〈 0.001] and a greater than 100% increase in the mean elimination half-life [2.03 (0.46) vs 4.29 (0.71) hr, P 〈 0.001] of theophylline were observed. These data demonstrate an acute inhibitory effect of amiodarone on the hepatic microsomal enzyme system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1016366008696
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  • 137
    Digitale Medien
    Digitale Medien
    Engineering Targeted In Vivo Drug Delivery. I. The Physiological and Physicochemical Principles Governing Opportunities and Limitations (1986)
    Springer
    Pharmaceutical research 3 (1986), S. 333-344 
    Details
    ISSN: 1573-904X
    Schlagwort(e): drug delivery, targeted ; prodrugs ; pharmacokinetics ; pharmacodynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract A physiologically based model is presented to aid prediction of the pharmacological benefits to be derived from the administration of a drug as a targeted drug–carrier combination. An improvement in the therapeutic index and an increase in the therapeutic availability are the primary benefits sought. A measure of the former is obtained from the value of the drug targeting index, a newly derived parameter. Both the drug targeting index and the therapeutic availability are directly calculable. The minimum information needed for approximating both parameters is the candidate drug's total-body clearance and some knowledge of the target site's anatomy and blood flow. Drugs with high total-body clearance values that are known to act at target tissues having effective blood flows that are small relative to the blood flow to the normal eliminating organs will benefit most from combination with an efficient, targeted carrier. Direct elimination of the drug at the target site or at the tissue where toxicity originates dramatically improves the drug targeting index value. The fraction of drug actually released from the carrier at both target and nontarget sites can radically affect index values. In some cases a 1% change in the fraction of the dose delivered to the target can result in a 50% change in the drug targeting index value. It is argued that most drugs already developed have a low potential to benefit from combination with a drug carrier. The approach allows one to distinguish clearly those drugs that can benefit from combination with targeted in vivo drug carriers from those drugs that cannot.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1016332023234
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  • 138
    Digitale Medien
    Digitale Medien
    Influence of Malnutrition on the Disposition of Metronidazole in Rats (1986)
    Springer
    Pharmaceutical research 3 (1986), S. 352-355 
    Details
    ISSN: 1573-904X
    Schlagwort(e): malnutrition ; metronidazole ; pharmacokinetics ; rats ; metabolism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The influence of dietary protein deficiency on the disposition of metronidazole and its two major metabolites was examined in male Sprague–Dawley rats fed for 4 weeks on a 23% (control-) or a 5% (low-) protein diet ad libitum. Following an intravenous bolus dose of 10 mg/kg metronidazole hydrochloride, blood samples were obtained serially for a period of 24 hr after drug administration. Serum concentration–time data were analyzed by nonlinear least-squares regression, as well as noncompartmental techniques. The average mean residence time (MRT) was significantly prolonged by 48%, while the systemic clearance (Cl) was decreased by 42% in the protein-deficient rats. Since there was no alteration in the apparent steady-state volume of distribution (V ss), the mean harmonic half-life was increased from 2.9 to 5.0 hr in the protein-deficient rats. Although the percentage of metronidazole recovered as total drug in the urine over 24 hr was not significantly different between the two groups of animals, rats on a low-protein diet excreted a significantly smaller percentage of the administered dose as unchanged metronidazole (mean ± SD, 24.6 ± 3.8 vs 36.5 ± 12%) and a larger percentage (16.7 ± 2.6 vs 8.3 ± 1.8%) as the hydroxylated metabolite. No significant difference in the partial metabolic clearance of the hydroxylated metabolite of metronidazole was seen between the two groups of animals; however, there was a significant decrease in the renal clearance of metronidazole (1.45 ± 0.68 vs 0.55 ± 0.06 ml/min/kg) in the rats fed a low-protein diet. We conclude that the decreased clearance of metronidazole in protein deficiency is a result primarily of the decreased glomerular filtration rate, decreased biliary excretion, and/or increased net tubular reabsorption of metronidazole.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1016433724142
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  • 139
    Digitale Medien
    Digitale Medien
    Bioavailability of Propranolol After Oral, Sublingual, and Intranasal Administration (1986)
    Springer
    Pharmaceutical research 3 (1986), S. 108-111 
    Details
    ISSN: 1573-904X
    Schlagwort(e): propranolol ; intranasal ; sublingual ; absorption ; bioavailability ; pharmacokinetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The bioavailability of propranolol was compared after oral, sublingual, and intranasal administration in eight healthy male volunteers. Relative to the bioavailability after intranasal (in) administration, which was previously shown to be nearly complete (F relin = 100%), the sublingual (sl) administration of a standard 10-mg tablet gave a bioavailability of F relsl = 63 ± 22%, while the oral (or) administration yielded only F relor = 25 ± 8%. The serum concentration–time curves of propranolol after sublingual administration resembled those of a sustained-release preparation. This sustained-release phenomenon after the sublingual route is reflected in the mean residence times (MRTs) of propranolol in the body (MRTor = 5.7 ± 1.3 hr, MRTsl - 6.4 ± 1.3 hr, MRTin = 4.6 ± 1.0 hr; mean ± SD; N = 8). MRTs after sublingual administration were significantly longer than after the oral and the intranasal doses (P 〈 0.05 and P 〈 0.002, respectively).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1016345504153
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  • 140
    Digitale Medien
    Digitale Medien
    Pharmacokinetics and Reversible Biotransformation of Sulfinpyrazone and Its Metabolites in Rabbits. I. Single-Dose Study (1986)
    Springer
    Pharmaceutical research 3 (1986), S. 173-177 
    Details
    ISSN: 1573-904X
    Schlagwort(e): sulfinpyrazone ; pharmacokinetics ; reversible metabolism ; single dose
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In rabbits receiving sulfmpyrazone (SO) and the sulfide metabolite (S) in four separate experiments, the biotransformation of SO into S was found to be reversible, which resulted in approximately parallel terminal disposition profiles for the three major substances in plasma, i.e., SO, S, and the p-OH-sulfide (OH-S). However, differences in disposition kinetics were observed between the intravenous and the peroral administration. The formation of OH-S was independent of both the administered compound and the administration route. The results obtained in the present studies, the previously documented enterohepatic recirculation, and the formation of S by hindgut flora may have implications for studies on sulfinpyrazone, which has been used as an antithrombotic agent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1016370209604
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  • 141
    Digitale Medien
    Digitale Medien
    Pharmacokinetics and Reversible Biotransformation of Sulfinpyrazone and Its Metabolites in Rabbits. II. Multiple-Dose Study (1986)
    Springer
    Pharmaceutical research 3 (1986), S. 178-183 
    Details
    ISSN: 1573-904X
    Schlagwort(e): sulfinpyrazone ; pharmacokinetics ; reversible metabolism ; multiple dose
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract In crossover studies rabbits were given sulfmpyrazone (SO) and its sulfide metabolite (S) perorally once daily (10 mg/kg) for 5 days. Comparison of the pharmacokinetic parameters obtained after the first and the fifth dose indicates that repeated dosing does not alter disposition kinetics of both SO and S, except that in dosing with S the observed terminal half-life for S is significantly reduced, from 4.59 ± 0.55 to 2.86 ± 0.6 hr (SD). In other studies rabbits were given higher single doses (15, 25, and 50 mg/kg) perorally and comparison was made between these dose sizes and the first dose (10 mg/kg) of multiple administration with S. Some kinetic parameters tended to be altered in a nonlinear fashion, and greater intersubject variations were observed because of the dose increase, while oxidation to SO or p-hydroxylation to OH-S from S was not significantly altered.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1016322326443
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  • 142
    Digitale Medien
    Digitale Medien
    Pharmacoclinical data on high dose medroxyprogesterone acetate in advanced breast cancer (1986)
    Springer
    Breast cancer research and treatment 8 (1986), S. 161-163 
    Details
    ISSN: 1573-7217
    Schlagwort(e): medroxyprogesterone acetate ; pharmacokinetics ; response ; toxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01807705
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  • 143
    Digitale Medien
    Digitale Medien
    Preparation of Optically Active Secondary Amines by Thermal Decomposition of (Methylbenzyl)urea Analogs: Absolute Configuration of (+)- and (-)-Mecamylamine. Preliminary CommunicationThe full paper will be published elsewhere.Patent application has been filed. (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 283-287 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Thermolysis of the (α-methylbenzyl)urea diastereoisomers 4 and 5 of (±)-mecamylamine ((±)-1) and 6 and 7 of (±)-1-noreseroline O-methyl ether ((±)-3) in refluxing alcohol afforded optically pure amines in high yield, besides optically pure carbamates of (α-methylbenzyl)amine which can be recycled. The absolute configuration of (-)-mecamylamine hydrochloride ((-)-1 · HCl) was determined by X-ray diffraction analysis.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690205
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  • 144
    Digitale Medien
    Digitale Medien
    2,5-Chinonmethide des 1,6-Methano[10]annulens mit S,N- und N,N-Acylketenacetal StrukturMeinem hochverehrten Lehrer, Prof. Dr. Siegfried Hünig, Würzburg, zum 65. Geburtstag gewidmet (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 315-328 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 2,5-Quinonemethides of 1,6-Methano[10]annulene with the Structures of S,N- and N,N-Acylketene AcetalsInvestigation on the chemical reactivities of 2-(tert -butoxy)-1,6-methano[10]annulene and the syntheses of the compounds 2, 4, 6-8, 11, 13-22 are described; the results of 1H- and 13C-NMR-spectroscopic measurements are reported.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690209
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  • 145
    Digitale Medien
    Digitale Medien
    1,2-Epoxycarotinoide. 6. Mitteilung. Isolierung von 1′,2′-Epoxy-1′,2′-dihydro-ε,ψ-carotin aus der ‘Delta-Mutanten’-Tomate (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 340-344 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 1,2-Epoxycarotenoids Isolation of 1′,2′-Epoxy-1′,2′-dihydro-ε,ψ-carotene from a ‘Delta Mutant’ TomatoFrom ‘Delta Mutant’ tomatoes, optically active 1′,2′-epoxy-1′,2′-dihydro-ε,ψ-carotene (7) was isolated. According to the CD data, the configuration is 6R and presumably 2′S.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690212
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  • 146
    Digitale Medien
    Digitale Medien
    (Cholestanyloxycarbonyl)benzyl esters as peptide substituents: Conformational properties of fully protected oligo-L-lysines with C-terminal (cholestanyloxycarbonyl)benzyl and benzyl ester moieties (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 350-358 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: This study involves L-lysine oligo peptides, protected at the N-terminus by the Nps and at the ε-amino functions by Boc groups. Two series were prepared from dimer to octamer, one containing the p-[(cholestan-3β-yloxy)carbonyl]benzyl, the other one the benzyl ester group at the C-terminus. Conformational analyses were performed by IR absorption. The occurrence of the intermolecular β-structure in the solid state and in CH2Cl2 solution was demonstrated for the highest oligomers. The relative stabilities of the self-associated species were determined by adding a variety of polar solvents to the CH2Cl2 solutions. The cholestanyl-containing peptides have a lower propensity to self-aggregate than the benzyl-ester analogues. Self-aggregation and decreasing solubility run in parallel. It was also directly shown that soluble urea derivatives may disrupt intermolecular H-bonds in CH2Cl2, a point of practical interest, particularly in solid-phase peptide synthesis.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690214
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  • 147
    Digitale Medien
    Digitale Medien
    Die toxischen und sedierend wirkenden Bufadienolide von Kalanchoedaigremontiana HAMETet PERR (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 359-367 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Toxic and Sedative Bufadienolides of Kalanchoe daigremontiana HAMET et PERR.From the toxic Crassulacee Kalanchoe daigremontiana five biosynthetically related bufadienolides have been isolated and structurally elucidated by X-ray and 1H- and 13C-NMR spectroscopy. The compounds were identified as bersaldegenin 1,3,5-orthoacetate (2), bersaldegenin 1-acetate (4), bersaldegenin 3-acetate (3), 1β,3β,5,11α,14-pentahydroxy-12,19-dioxo-5β,14β-bufa-20,22-dienolide 1,3,5-orthoacetate ( = daigremontianin; 1), and 3β-acetoxy-1β,5,14-trihydroxy-5β,14β-bufa-20,22-dienolide ( = daigredorigenin-3-acetate, 5). According to the pharmacological investigations, the two orthoacetates 1 and 2 comprise the positive inotropic, sedative, and toxic activity of the plant.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690215
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  • 148
    Digitale Medien
    Digitale Medien
    Enantioselective Synthesis of D-erythro-Sphingosine and of Ceramide (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 368-373 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The enynol 2 was transformed into D-erythro-sphingosine 11 (7 steps, 46%) and into ceramide 1 (8 steps, 41% overall yield). The key steps were the mono-epoxidation of the enynol 5 (Ti(t-BuO)4, (-)-D-diethyl tartrate, t-BuOOH) to 6 (86%, ≥ 98% ee), the regioselective intramolecular opening of the oxirane 6 via the benzylurethane 7, and the reductive tranformation of the acetylene 9 into the oxazolidinone 10 (Li, EtNH2, 88%).
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690216
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  • 149
    Digitale Medien
    Digitale Medien
    An ESR Study of the Radical Cations of Tetrathiafulvalene (TTF) and Electron Donors Containing the TTF Moiety (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 141-151 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Hyperfine data and g factors are reported for the radical cations of tetrathiafulvalene (TTF; 1) and of its derivatives 2-13. From the intense satellite spectra of 1+-13+ not only the coupling constants of the 33S isotopes in the TTF moiety could be determined, but also, in favourable cases, those of the 13C isotopes in the central double bond. The former values range from 0.370 (8+) to 0.470 mT (4+) and the latter from 0.255 (8+) to 0.360 mT (4+) in the radical cations of bis(ethylenedithio)-TTF (8+) and tetracyano-TTF (4+). The radical cation of TTF (1+) exhibits intermediate values, 0.425 for the 33S and 0.285 mT for the 13C isotopes. The spin population in 1+-13+ resides, to a large extent, in the central S2C = CS2 part of the π-system. It tends to increase (decrease) by substitution with electron-accepting (donating) groups in the 2,3,6,7-positions of TTF.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690117
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  • 150
    Digitale Medien
    Digitale Medien
    Conformation-Odor Relationships in Norlabdane Oxides (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 163-173 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Conformational factors have been found responsible for the dramatic change in odor between (-)-deoxyambreinolide (12) and its (+)-epi derivative 13. The presumably molecular event during the receptor interaction has been simulated by the diastereoisomeric 11-methyl-ambrox derivatives 3 and 5 as model compounds.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690120
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  • 151
    Digitale Medien
    Digitale Medien
    Crystal Structures of Chiral Ionophores: Bis(9,9′-spirobifluorene)-26-crown-4 and -32-crown-6 (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 626-631 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The X-ray crystal structures of bis(9,9′-spirobifluorene)-26-crown-4βbenzene solvate (monoclinic, a = 15.47 Å, b 11.265 Å, c = 15.220 Å, β = 91.54°, space group C2) and bis(9,9′-spirobifluorene)-32-crown-6·dichloromethane solvate (tetragonal, a = 20.958 Å, c = 11.779 Å, space group P41212) are described. Both compounds act as enantioselective ionophores for α-aminoalcohols.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690312
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  • 152
    Digitale Medien
    Digitale Medien
    Steric Effects on Reaction Rates. Part VIII. The Significance of Front Strain Release in Solvolysis of Bridgehead Derivatives (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 635-645 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The steric requirements of leaving groups for 14 bridgehead derivatives have been examined using MM2 calculations. The strain varies almost monotonously throughout the series upon variation of the leaving group from H to C1, OH, CH3, CH3CH2O, (CH3)3CO, (CH3)3C and no significant trends for differential F-strain effects are detected expect for the perhydrophenalene derivative 13. The experimental rates of solvolysis of bridgehead derivatives correlate well with the calculated steric energy differences between substrate R-X and the corresponding carbenium ion R⊕. However, the strain calculations using the more recent force-fields (MM2) disagree, in part, with those reported in the literature: chloride and p-toluenesulfonate leaving groups correlate with identical slopes, and the perhydrotriquinacene derivative 10 shows no anomalous behavior. The calculations suggest that F-strain and C,C-hyperconjugation should not play any dominant role in bridgehead solvolysis.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690314
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  • 153
    Digitale Medien
    Digitale Medien
    Die Synthese und der thermische Zerfall des 1,2-Diazabenzo[e]-semibullvalens und dessen Beziehung zur Thermolyse des Benzobenzvalens (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 670-675 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Synthesis and the Thermal Decay of 1,2-Diazabenzo[e]semibullvalene and its Relation to the Thermolysis of BenzobenzvaleneThe [4 + 2]-photoadduct of naphthalene and 4-phenyl-4H-1,2,4-triazol-3,5-dione (PTAD) was subjected to a triplet-sensitized di-π-methane rearrangement. Hydrolysis of the resulting urazol 15 gave a stable semicarbazide 16 which by nickel-peroxide oxidation gave 1,2-diazabenzo[e]semibullvalene (10). At 40 °C, the latter decays in CHCl3 solution to produce benzofulvene (2) as the principal product, accompanied by benzobenzvalene (1) and small amounts of naphthalene. This decay reaction is rationalized in terms of a 1,3-dipolar cycloreversion which is followed by denitrogenation to give indenyl carbene (19). The thermolysis of 1 in solution is believed to proceed via the same carbene. At present, these findings provide only a partial answer to the benzobenzvalene enigma (i.e., in solution at 150°, 1 gives 2, but in the gas-phase at 300°, 1 yields naphthalene). MeOH is shown to add readily to 10 in a homologous Michael addition.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690317
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  • 154
    Digitale Medien
    Digitale Medien
    Formale Totalsynthese von (±)-Isocomen durch Anwendung der α-Alkinon-Cyclisierung (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 659-669 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Formal Total Synthesis of (±)-Isocomen by Application of the α-Alkinon CyclizationA total synthesis of the racemic form of the sesquiterpene isocomene (A) was accomplished by application of the cyclopentenone anellation B→D (Scheme 1) which includes the α-alkynone cyclization C→D, a gas-phase flow thermolytic process. Starting with the known product 2 (Scheme 3) of the anellation B→D, the elaboration of ring C of A proceeded in 9 steps to the α-alkynone 16 (Scheme 5) which was cyclized at 540° selectively to give the angularly fused triquinane 4 (77%). A two-step procedure then led to 5 (Scheme 6), a last but one intermediate in a known total synthesis of (±)-A. The conversion of 16 to 4 also demonstrated the compatibility of an acetoxy function with the anellation sequence B→D.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690316
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  • 155
    Digitale Medien
    Digitale Medien
    Photochemical Rearrangements of 5,6-Epimino-5,6-dihydro-β-ionone and Derivatives (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 692-697 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: On irradiation at -20°, 5,6-epimino-5,6-dihydro-β-ionone (E)-3 rearranges to the products 6 and 7. The N-methyl derivative (E)-4 does not lead to any photoproduct upon brief irradiation; on prolonged irradiation, only unspecific photodecomposition is observed. The N-acylated derivative (E)-5 undergoes rapid (E)/(Z)-isomerization and slow rearrangement to 12 and 13.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690320
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  • 156
    Digitale Medien
    Digitale Medien
    Pteridine. Teil LXXX.Teil LXXIX: [1]. Synthese, Reaktionen und Photochemie von Pteridinthionen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 708-717 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis, Reactions, and Photochemistry of PteridinethionesThe pteridine-6(5H)-thione 1 and various pteridine-7(8H)-thiones (13, 22, 26) have been synthesized, and their photochemical reactivity has been investigated under aerobic conditions. The formation of different photooxidation products is pH-dependent. In acidic to neutral media, disulfides (2, 15, 23, 29) are formed, whereas neutral to alkaline solutions favour the formation of pteridinesulfinic (3, 17) and -sulfonic acids (6, 16, 24, 30). Prolonged irradiation of the disulfides 2 and 15 led to the intensively yellow fluorescing bis(thio)dilumazines 19 and 20, respectively.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690323
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  • 157
    Digitale Medien
    Digitale Medien
    Cacospongione A, cacospongienone A, and cacospongienone B, new C21 difuran terpenoids from the marine sponge Cacospongiascalaris SCHMIDT of the Côte d' Azur (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 726-733 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The sponge Cacospongia scalaris (family Thorectidae), collected at the Cap de Nice (Cǒte d'Azur), is shown to contain a series of truncated, linear C21 difuran terpenoids comprising the known sponge products furospongin-1 ((+)-1), furospongin-2 (2), and dihydrofurospongin-2 ((-)-(E)-3), besides the new products cacospongione A ((-)-4), cacospongienone A ((-)-(Z)-6), and cacospongienone B ((-)-(E)-6), whose absolute configurations have been assigned by chemical correlations with (+)-1. Possibly, one of the two cacospongienones is an artifact, as these two terpenoids interconvert on standing. This is the first finding of linear C21 difuran terpenoids, which are typical of the Spongiidae, in a member of the family Thorectidae.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690325
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  • 158
    Digitale Medien
    Digitale Medien
    Mitteilungen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 749-750 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690327
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  • 159
    Digitale Medien
    Digitale Medien
    Deoxy-nitrosugars 12th communication11th Communication: [1]. Synthesis of isosteric mono-phosphonate analogues of β-and α-D-fructose 2,6-bisphosphate (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 751-760 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A synthesis of the isosteric mono-phosphonate analogues 2a and 19 of the β-and α-D-fructose 2,6-bisphosphate, respectively, is described. Chain elongation of the 1-deoxy-1-nitro-D-arabinose 3 (Scheme 1) by a Henry reaction with paraformaldehyde followed by protection of the resulting alcohol (methoxymethyl ether) and a radical-chain substitution by nitromethane anion gave the key intermediates, the gluco-anhydroalditol 6 and the manno-anhydroalditol 7. These products equilibrated under basic conditions. Conversion of 7 to the aldehyde 9, Abramov reaction of 9 with diphenyl phosphite followed by deoxygenation according to Barton gave the phosphonate 11 (Scheme 2). Selective hydrogenolysis of 11, phosphorylation and deprotection gave 2 which was converted to the tetrasodium salt 2a. Similarly, 6 was transformed into the isosteric phosphonate analogue 19 of the α-D-fructose 2,6-bisphosphate (Scheme 3).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690402
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  • 160
    Digitale Medien
    Digitale Medien
    Sequence dependence of secondary-structure formation part IVPart III: [1]. Helix-forming potential of amphiphilic oligopeptides containing aib residues (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 786-792 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The conformational properties of Aib-containing oligopeptides having the propensity to adopt amphiphilic helical conformations were investigated by CD spectroscopy in solution. The peptides CF3COOH.H-Pro-Glu-[Ala-Aib-Glu-Aib-]4Gly-OH (I), HCl.H-Pro-Ala-Aib-[Gul-Ala-Ala-Aib-]2Glu-Ala-Aib-Gly-PEGM (II), and CF3COOH.H-Ala-Aib-[Glu-Glu-Ala-Aib-]3PEGM (III) were synthesized according to the general principles of the liquid-phase method for peptide synthesis. Peptides I-III exhibit helical conformations in CF3CH2OH, MeOH, and in H2O at acidic pH; however, at pH 7, only II forms a stable helix, whereas I and III are predominantly in an unordered conformation. Some general features for the construction of amphiphilic helices are discussed in the light of the experimental data.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690405
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  • 161
    Digitale Medien
    Digitale Medien
    Conformational Analysis of Endoperoxides Grafted onto Bicyclo[2.2.n]alkanes as a Test of the Rigidity of the Bicyclic Skeleton. Photo-oxidation of [2.2.2] Hericene and 2,3,5,6-Tetramethylidenebicyclo[2.2.n]alkanesInteraction between non-conjugated chromophores, Part 24. Part 23, see [1a]. For a preliminary report, see communication No. ONII-10, Autumn Meeting of the Swiss Chemical Society, Bern, Oct. 18, 1985. (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 761-772 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The photo-oxidation of [2.2.2]hericene (6) gave successively the endoperoxides 11 (9,10,11,12-tetramethylidene-4,5-dioxatricyclo[6.2.2.02,7]dodec-2(7)-ene), the bis-endoperoxide 16 (15,16-dimethylidene-4,5,11,12-tetraoxatetracyclo[6.6.2.02,7.o9,14]hexadeca-2(7),9(14)-diene), and the tris-endoperoxide 19 (4,5,11,12,17,18-hexaoxapentacyclo[6.6.6.02,7.09,14.015,20]icosa-2(7),9(14),15(20)-triene). The endoperoxides 11, 16, and 19 were formed in the presence or in the absence of a dye sensitizer. The sensitized photo-oxidations of 2,3,5,6-tetramethylidenebicyclo[2.2.2]octane (4), 5,6,7,8-tetramethylidenebicyclo[2.2.2]oct-2-ene (5), 2,3,5,6-tetramethylidenebicyclo[2.2.1]-heptane (7), and 2,3,5,6-tetramethylidene-7-oxabicyclo[2.2.1]heptane (8) gave successively the corresponding mono-endoperoxides 9, 10, 12, and 13 and the bis-endoperoxides 14, 15, 17, and 18, respectively. Low-temperature NMR spectra of the bis-endoperoxides 14 and 16 indicated that their C2 and Cs conformers have the same stability. Similarly, there was no difference in the enthalpy of the D3 and C2 conformers of the tris-endoperoxide 19. The following reactivity sequence was observed for the sensitized photo-oxidations of 6-8 and 5,6-dimethylidene-7-oxabicyclo[2.2.1]hept-2-ene (23): 6 + 1O2→11 〉 7 + 1O2→12〉8 + 1O2→13〉23 + 1O2→24, a trend parallel with that reported for the ethylenetetracarbonitrile (TCNE) cycloadditions to the same polyenes. The rate-constant ratios k1/k2 and k2/k3 for the three successive photo-oxidations of [2.2.2]hericene (6) did not differ significantly from unity, in contrast with the Diels-Alder additions of 6. Similarly, the rate-constant ratios k1/k2 for the two successive photo-oxidations of tetraenes 7 and 8 were significantly smaller than those reported for the successive TCNE cycloadditions to 7 to 8. The endoperoxide formations are not sensitive to the change in the exothermicity of the reactions but they are sensitive to the electronic properties (IP's) of the polyenes.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690403
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  • 162
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    Digitale Medien
    Ion-Molecule reaction in the gas phase part VIFor Part V, see [1]. Regioselective SN2 reaction from terpenoid diastereoisomeric diols using CI/NH4+Dedicated to Prof. Tino Gäumann on the occasion of his 60th birthday (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 806-815 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A stereospecific and regioselective SN2 mechanism (Walden inversion) is observed during studies involving modified terpenoid epimeric diols in a high-pressure ion source using ammonia as a reagent gas.
    Zusätzliches Material: 4 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690408
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  • 163
    Digitale Medien
    Digitale Medien
    Three Novel Spin-Labeled Substrates for Enzymatic Incorporation into Nucleic Acid Lattices (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 345-349 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The synthesis of one C(4)-spin-labeled uridine-5′-diphosphate (C(4)-UDP) and two nitroxide-containing 2′-deoxyuridine-5′-triphosphate (dUTP) analogs are reported. The C(4)-UDP derivative was incorporated into copolymers by polynucleotide phosphoxylase (PNPase); one of the two dUTP analogs, substituted at position C(4), was a good substrate for TdT, whereas the other one, substituted at position C(5), served as substrate for E. coli DNA polymerase (Pol I).
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690213
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  • 164
    Digitale Medien
    Digitale Medien
    Reaktionen von 3-substituiertem 5-Trifluormethyl-1,3,4-oxadiazol-2(3H)-on mit NucleophilenIX. Mitt. über Synthese von Heterocyclen. VIII. Mitt. s. [1].Vorgetragen an der Herbstversammlung der Schweizerischen Chemischen Gesellschaft am 18. Oktober 1985 in Bern. (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 333-339 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reactions of 3-Substituted 5-Trifluoromethyl-1,3,4-oxadiazol-2(3H)-one with NucleophilesThe 3-substituted 5-trifluoromethyl-1,3,4-oxadiazolones 3, 4, 13, and 15 are attacked by N- and S-nucleophiles either at the ring C-atom C(2) or C(5). Depending on the nature of the substituent and the nucleophile, the ring-opening products 7, 10, 12, and 14 or the ring-enlargement products 16 are formed. The reaction of 4 with thiols is a novel variant of the Grob-type fragmentation. The reactivity of the 1,3,4-oxadiazolones is compared with that of the analogous 1,3,4-thiadiazolones. The structures of the new compounds were elucidated by 1H- and 13C-NMR spectroscopy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690211
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  • 165
    Digitale Medien
    Digitale Medien
    Synthese von 4,4-disubstituierten 1,3-Thiazol-5(4H)-thionen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 374-388 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis of 4,4-Disubstituted 1,3-Thiazol-5(4H)-thionesAn easy synthesis for the 1,3-thiazol-5(4H)-thiones 5, a class of heterocycles which have hitherto only been available with difficulty, is described. Reaction of 3-amino-2H-azirines 25 with thiocarboxylic acids at 0° yields monothiodiamides of type 20 (Scheme 6) which, on treatment with Lawesson reagent at 100°, undergo thiation and cyclization to give 5 in good yield.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690217
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  • 166
    Digitale Medien
    Digitale Medien
    Herstellung von disubstituierten Maleinsäure-anhydriden mit Hilfe von reaktiven 2-Oxo-3H-imidazo[1,2-a]pyridinium-Verbindungen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 396-403 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Preparation of Disubstituted Maleic Anhydrides from Reactive 2-Oxo-3H-imidazo[1,2-a]pyridinium CompoundsA new useful method for the preparation of disubstituted maleic anhydrides, most of them bearing additional functional groups in the side chain, is described. The key step of the synthesis consists of the addition of 2-oxo-3H-imidazo[1,2-a]pyridinium compounds to a variety of different Michael acceptors.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690219
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  • 167
    Digitale Medien
    Digitale Medien
    Konfigurationsbestimmung von geometrischen Isomeren mittels selektiver 13C{1H}-NOE-Differenzspektroskopie (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 898-904 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Application of Selective 13C{1H}-NOE Difference Spectroscopy in Determination of the Configuration of (Z)/(E)-IsomersHeteronuclear 13C{1H}-NOE studies have been performed to elucidate the configuration at the imino double bond in N,N′-Dicyanoquinonediimines. Selective low-power irradiation of the neighbouring ring protons in compounds 1-5 increases the signal intensities of CN as well as of the imino-C-atoms in the 13C-NMR spectra. The increase of signal intensity can easily be detected by the difference spectroscopy. The results of this investigation are in good agreement with a recently published study on the stereochemistry of N,N′-Dicyanoquinonediimines, based on the interpretation of 13C-chemical shifts.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690417
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  • 168
    Digitale Medien
    Digitale Medien
    Synthese und Strukturaufklärung von Merucathin und Pseudomerucathin. Zwei Inhaltstoffe von Catha edulis FORSK (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 918-926 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis and Structure Elucidation of Merucathine and Pseudomerucathine. Two Constituents of Catha edulis FORSK.Starting from L-alanine, two constituents of Catha edulis FORSK. (3R,4S)-4-amino-1-phenyl-1-penten-3-ol ((3R,4S)-4, merucathine) and (3S,4S)-4-amino-1-phenyl-1-penten-3-ol ((3S,4S)-4, pseudomerucathine) were synthesized.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690420
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  • 169
    Digitale Medien
    Digitale Medien
    Mitteilungen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 955-956 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690424
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  • 170
    Digitale Medien
    Digitale Medien
    1,4-Dithiafulvene aus der Umsetzung von 4,4-disubstituierten 1,3-Thiazol-5(4H)-thionen mit AcetylenderivatenVorläufige Mitteilung s. [1]. (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 419-429 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 1,4-Dithiafulvenes, Products of the Reaction of 4,4-Disubstituted 1,3-Thiazol-5(4H)-thiones and Acetylenic CompoundsOn heating in toluene, 4,4-disubstituted 1,3-thiazol-5(4H)-thiones 1 and acetylenecarboxylates or acetylenecarbonitriles 2 undergo a cyclosubstitution reaction to yield 2-methylidene-1,3-dithiol derivatives 3 (1,4-dithiafulvenes) and a nitrile. Further heating of 3a and 3b in the presence of excess 2a leads to the isomeric 2,3-dihydrothiophene-2-thiones 4a and 4b, respectively. The benzodithiafulvene 14 has been formed in a similar reaction from 1a and in situ generate benzyne.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690223
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  • 171
    Digitale Medien
    Digitale Medien
    Perimeter-Type Structures in Charged [4n + 2] Annuleno [4n + 2] annulenes. The Importance of the Frontier-Orbitals (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 949-954 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The tetra(tert-butyl)[14]annuleno[14]annulene 1 is transformed, via alkali metal reduction, into its radical monoanion, dianion, radical trianion, and tetraanion. The paramagnetic species are characterized by ESR and ENDOR spectroscopy and the diamagnetic species by 1H- and 13C-NMR spectroscopy. Well-resolved ESR and NMR spectra can only be obtained, if the reduction is carefully monitored. For the interpretation of the data, the ions derived from the structurally related [14]- and [22]annulenes 3 and 5 as well from the tetra(tert-butyl)[14]annuleno[18]annulene 2 serve as suitable model compounds. While the behavior of the neutral annulenoannulene 1 is governed by that of the [14]annulene-subunit, the corresponding ionic systems can best be described as macrocyclic perimeters. This outcome can be rationalized by the nodal properties of the frontier MO's.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690423
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  • 172
    Digitale Medien
    Digitale Medien
    Stereoselective Reduction of δ-Hydroxy-β-ketoesters (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 803-805 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reduction of δ-hydroxy-β-ketoesters 1 was investigated with three different reducing agents. In several instances, high selectivity in favor of syn-1,3-diols was observed.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690407
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  • 173
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    Digitale Medien
    Anion Selectivity of Metalloporphyrins in Membranes (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 849-854 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Lipophilic Co(III) and Mn(III) complexes of 5,10,15,20-tetrakis[4-(hexyloxycarbonyl)phenyl]porphyrin act as positively charged carriers for anions and induce anion selectivities in membranes clearly deviating from the sequence of classical anion exchangers. Different anion selectivities are observed for the Co(III) and Mn(III) porphyrins.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690411
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  • 174
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    Digitale Medien
    Approaches to 1H-Cyclopropa[l]phenanthrenes. Eliminations with 1a,9b-Dihydro-1H-cyclopropa[l]phenanthrene Derivatives (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 855-864 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Base-induced elimination of the sulfonium salt 2i in the presence of furan affords the addition products 7 and 8, derived from 1H-cyclopropa[l]phenanthrene (1) and the isomeric cyclopropene 5a (Scheme 3). Upon oxidation, the selenide 2c yields phenanthrene-9-methanol (9), presumably via 1. No evidence for the intermediate 1 is obtained from sulfoxide pyrolysis with 2e, which leads to products formed by radical pathways (Scheme 5). Reductive elimination of the disulfone 3b gives half-reduction to monosulfone 2g and complete reduction to cyclopropane 2 as well as 9-methylphenanthrene (15), but no evidence for the intermediate 1.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690412
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  • 175
    Digitale Medien
    Digitale Medien
    Fluorine-Containing Organozinc Reagents Part 1 A Simple Synthesis of 2,2-Dichloro-3,3,3-trifluoropropanol (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 881-886 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The title compound 1, which can be regarded as a synthetic equivalent of substituted 1,1,1-trifluoroacetone 2, is prepared by Zn-induced reductive addition of 1,1,1-trichloro-2,2,2-trifluoroethane (3) to formaldehyde (4). A brief survey of the scope of this C—C-bond formation leading to a variety of new CF3-containing synthetic building blocks is also given.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690415
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  • 176
    Digitale Medien
    Digitale Medien
    Intramolekulare 1,3-dipolare Cycloadditionen mit alkenyl-substituierten 3,4-DiarylsydnonenTeilweise in vorläufigen Mitteilungen veröffentlicht [1] [2].Als Sydnone werden mesoionische 1,2,3-Oxadiazol-5-one (1,2,3-Oxadiazolium-5-olate, Anhydro-5-hydroxy-1,2,3-oxadiazolium-hydroxide) bezeichnet [3]. (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 927-940 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Intramolecular 1,3-Dipolar Cycloaddition Reactions of Alkenyl-substituted 3,4-DiarylsydnonesThe 3,4-diarylsydnones 1 and 12a-e with an allyl or alkenyloxy substituent on the N(3)-phenyl group have been synthesized by classical methods starting from 2-allylaniline and the corresponding alkenyloxyanilines, respectively (Schemes 2 and 3). Whereas the allyl-substituted sydnone 1 undergoes an intramolecular 1,3-dipolar cycloaddition at room temperature in solution to yield 13 (Scheme 4), the alkenyloxy-substituted sydnones 12a-e are thermally stable. On irradiation of 1 and 12a-d, formation of the fused dihydropyrazoles 2 and 14a-d (Schemes 1 and 5) is observed. In the case of 12d, the yield of 14d is very low, and the symmetric 1,2,3-triazole 15a has been isolated as the main product. A very likely reaction mechanism for the formation of the photoproducts involves decarboxylation of the sydnones to give a nitrile-imine which undergoes an intramolecular 1,3-dipolar cycloaddition onto the C=C bond.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690421
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  • 177
    Digitale Medien
    Digitale Medien
    Intramolecular Oxygen Transfer on the Ozonolysis of a Diphenylcyclopentene Derivative (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 941-948 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The ozonolysis of cis-3,4a,7,7a-tetrahydro-3,3-dimethyl-6,7a-diphenylcyclopenta[1,2,4]trioxine (1) in CH2Cl2 at -78° gave the secondary endo ozonide 2 (43% yield) and an acetal 3 (27% yield) derived from O-insertion at the ortho position of the C(7a) phenyl substituent. Both structures were elucidated by X-ray. Repetition of the ozonolysis in MeOH/CH2Cl220:3 at -78° also gave the same two products in 12 and 15% yields, repectively, together with the hemiperacetal 4 (54% yield) formally derived from the secondary ozonide by addition of MeOH.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690422
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  • 178
    Digitale Medien
    Digitale Medien
    Masthead (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986) 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690501
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  • 179
    Digitale Medien
    Digitale Medien
    Isoswerosid, ein neues Secoiridoidglycosid aus den Wurzeln des Zwergholunders Sambucus ebulus L. (Caprifoliaceae). 2. Mitteilung über die Inhaltsstoffe der Zwergholunderwurzel (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1113-1119 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Isosweroside, a New Secoiridoid Glycoside from the Roots of Sambucus ebulus L. (Caprifoliaceae)The paper describes the isolation and structure elucidation of isosweroside (6-(β-D- glucopyranosyloxy)-methyl-9-vinyl-2,8-dioxabicyclo[3.3.1]non-6-en-3-one), the first Valeriana-type secoiridoid glycoside from the roots of Sambucus ebulus L. along with the two known glycosides ebuloside and morroniside.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690519
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  • 180
    Digitale Medien
    Digitale Medien
    Synthèse d'acétals de désoxy-3-hydroxyamino-3-furannoses. Note de laboratoire (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1132-1136 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Synthesis of 3-Deoxy-3-(hydroxyamino)furanose AcetalsReduction of sugar ketoximes with NaBH3CN under acidic conditions constitutes a good synthetic pathway to deoxy(hydroxyamino)sugar derivatives. These compounds which are useful building blocks for the preparation of analogs of various classes of biologically important carbohydrates are reasonably stable.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690521
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  • 181
    Digitale Medien
    Digitale Medien
    1,3-Dioxanone Derivatives from β-Hydroxy-carboxylic Acids and Pivalaldehyde. Versatile Building Blocks for Syntheses of Enantiomerically Pure Compounds. A Chiral Acetoacetic Acid Derivative Preliminary Communication (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1147-1152 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: (R)-3-Hydroxybutyric acid (from the biopolymer PHB) and pivalaldehyde give the crystalline cis - or (R,R)-2-(tert-butyl)-6-methyl-1,3-dioxan-4-one (1a), the enolate of which is stable at low temperature in THF solution and can be alkylated diastereoselectively (→3, 4, 5, and 7). Phenylselenation and subsequent elimination give an enantiomerically pure enol acetal 10 of aceto-acetic acid. Some reactions of 10 have been carried out, such as Michael addition (→11), alkylation on the CH3 substituent (→13), hydrogenation of the C=C bond (→1a) and photochemical cycloaddition (→16). The overall reactions are substitutions on the one stereogenic center of the starting β-hydroxy acid without racemization and without using a chiral auxiliary.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690523
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  • 182
    Digitale Medien
    Digitale Medien
    Diastereoselectivity and Reactivity in the Diels-Alder Reactions of α-Chloronitroso Ethers (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1137-1146 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The structure of the α-chloronitroso ether 1, obtained from the hydroximolactone 2 and tert-butyl hypochlorite (89%), was established by X-ray crystallographic analysis. The [4 + 2] cycloadditions of 1 with the dienes 3 and 8-11 led to the N-unsubstituted 3,6-dihydro-2H-1,2-oxazines 6 and 12-16 in high enantiomeric excess (Table 1). Due to the additional α-alkoxy group, the reactivity of 2 is much superior to the one of known α-chloronitrosoalkanes. The reactive conformation of 1 was deduced from the X-ray analysis as well as the high diastereoselectivity of the cycloadditions. The importance of the α-alkoxy group was evidenced from the similar reactivity of the racemic α-chloronitroso ethers 25-27 which were prepared from the hydroximo ethers 28-30 and tert-butyl hypochlorite.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690522
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  • 183
    Digitale Medien
    Digitale Medien
    Desoxy-nitrozucker 14. Mitteilung13. Mitteilung: [1]. 1-C-Nitroglycale. Herstellung und Umsetzung mit einigen Stickstoff-Nucleophilen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1191-1204 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 1-C-Nitroglycals. Preparation and Reaction with Some Nitrogen NucleophilesAcetylation of the 1-deoxy-1-nitromannopyranoses 2 and 6 was accompagnied by spontanous β-elimination to give the 1-C-nitroglucals 3 and 7, respectively, while acetylation of the gluco- and galacto-configurated 1-deoxy-1-nitropyranoses 8 and 14 gave the acetates 9 and 15, respectively (Scheme 1). The acetylation of the ribo- and arabino-configurated 1-deoxy-1-nitrofuranoses 19 and 21 also occurred without β-elimination to give the acetates 20 and 22, respectively (Scheme 2). Mild base treatment of the previously described O-acetylnitro-β-D-glucose 4, the O-acetylnitro-β-D-pyranoses 9 and 15, and the O-acetylnitro-β-D-furanoses 17, 20, and 22 gave the 1-C-nitroglycals 3, 10, 16, 18 and 23, respectively (Scheme 1 and 2). The previously obtained 1-C-nitroglucal 3 was deacetylated by treatment with MeOH in the presence of KCN or sodium m-nitrophenolate to give the free nitroglucal 5. Deacetylation of the benzylidene protected 1-C-nitroglucal 10 (MeOH, NaOMe) gave the 4,6-O-benzylidene-1-C-nitroglucal 11 and traces of the 2-O-methyl-1-C-nitromannoses 12 and 13. The UV, IR, 1H-NMR and 13C-NMR spectra of the 1-C-nitroglycals are discussed. In solution, the 1-C-nitroglycals 1, 5, 7, 10, 11, and 16 adopt approximately a 4H5- and 3 a flattened 4H5 conformation. The structure of 5 was established by X-ray analysis. In the solid state, 5 adopts a sofa conformation, which is stabilized by an intramolecular H-bond. The β-addition of NH3 to the 1-C-nitroglucals 7 and 10 was followed by an O→ N acetyl migration to give exclusively anomeric pairs of the N-acetyl-1-nitromannosamine derivatives 24/25 and 26/27, respectively (Scheme 3). The β-addition of methylamine, octadecylamine, and tryptamine to the 1-C-nitroglucal 11 also stereoelectronically controlled and gave the crystalline N-alkyl-1-nitromannosamines 28, 29, and 30, respectively. The stereoelectronically controlled β-addition of NH3 to the 1-C-nitrogalactal 16, followed by acetylation, yielded exclusively the talosamine derivative 31, while the reversible β-addition of azide ions to 16 gave the anomeric 2-azido-1-nitrogalactoses 32 and 33. The β-addition of azide ions to the 1-C-nitroglucal 1 led to the 2-azido-1-nitromannose 34. In the presence of excess formaldehyde, this addition was followed by a Henry reaction. Chromatography of the crude product was accompagnied by solvolytic removal of the NO2 group to give the 3-azidomannoheptulose 35 in high yields (Scheme 4).
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690527
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  • 184
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    Digitale Medien
    Comparison of the Complexation of Open-Chain and Cyclic N2S2 Ligands with Cu+ and Cu2+ (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1216-1223 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The complexation properties of the open-chain N2S2 ligands 1-4 are described and compared to those of analogous N2S2 macrocycles 5-7. With Cu2+, the open-chain ligands give complexes with the stoichiometry CuL2+ and CuLOH+, the stabilities and absorption spectra of which have been determined. The ligand field exerted by these ligands is relatively constant and independent of the length of the chain. With Cu+, the species CuLH23+, CuLH2+, and CuL+ were identified and their stabilities measured. The redox potentials calculated from the equilibrium constants and measured by cyclic voltammetry agree and lie between 250 and 280 mV against SHE. The comparison between open-chain and cyclic ligands shows that (1) a macrocyclic effect is found for Cu2+ but not for Cu+, (2) the ligand-field strength is very different for the two types of ligands, and (3) the redox potentials span a larger interval for the macrocyclic than for the open-chain complexes.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690529
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  • 185
    Digitale Medien
    Digitale Medien
    Nucleotides. Part XXVPart XXIV: [1].. Chemical synthesis of the hexaribonucleotide C-A-A-C-C-A (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1768-1777 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The chemical synthesis of the ribo-hexamer C-A-A-C-C-A has been achieved by two different routes applying the phosphotriester approach and using the (p-nitrophenyl)ethyl group for phosphate protection. The 2′-hydroxy groups as well as the terminal 2′,3′-diol function have been blocked by the (tert-butyl) dimethylsilyl group as permanent protection throughout all the synthetic steps with great success. Final deblocking of all protective groups could be performed with 80% yield to give the hexamer 23. The various protected intermediates have been characterized by elemental analysis and UV spectra.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690734
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  • 186
    Digitale Medien
    Digitale Medien
    Errata (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1787-1787 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690736
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  • 187
    Digitale Medien
    Digitale Medien
    The Formation of Bridged Bicyclic 1,2,4-Trioxanes by Intramolecular Capture of β-Hydroperoxy Cations (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1778-1786 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The 1,4-endoperoxide, prepared from 3-(4-methylnaphth-1-yl)propanal by photo-oxygenation in CH2Cl2, gave on treatment with Amberlyst-15®, 3,10b-epidioxy-2,3,4a,10b-tetrahydro-6-methyl-1H-naphtho[2,1-b] pyran in 85% yield. Its structure was determined by X-ray crystal structure analysis. The 1,2,4-trioxane moiety is locked in a twist-boat conformation with trans fusion to the parent six-membered ring. The 1,4-endoperoxides of the methyl, butyl, and phenyl ketone analogues of the aforementioned aldehyde underwent similar acid-catalyzed rearrangement to the corresponding bridged bicyclic trioxanes in 94, 47, and 48% yields, respectively.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690735
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  • 188
    Digitale Medien
    Digitale Medien
    New Synthetic Routes to β-Olefinic Trialkoxyphosphonium Salts and Phosphonates: Organometallic Variants of the Michaelis-Arbuzov ReactionReactions with Metal-Coordinated Olefins, Part V. Part IV: see [1]. Presented in part at the XIIth International Conference on Organometallic Chemistry, Vienna, September 1985. (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1757-1767 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The low-temperature addition of tertiary phosphites to [(allyl)Fe (CO)4]+X- complexes proceeds regio- and stereospecifically and produces metal-coordinated β-olefinic trialkoxyphosphonium ions. These can be converted by various routes into the uncomplexed phosphonium salts or phosphonates. Similar reactions of acyclic [(dienyl)Fe(CO)3]+X- compounds give metal-coordinated (2,4-dien-1-yl)trialkoxyphosphonium salts or dialkyl (2,4-dien-1-yl)phosphonates. The mechanisms and their relationship to the classical Michaelis-Arbuzov reaction are discussed. The new compounds are characterized, if possible, by 1H-, 13C-, and 31P-NMR spectra. The new phosphonium salts and phosphonates, potentially useful for Wittig-Horner reactions, are difficult to obtain by conventional routes.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690733
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  • 189
    Digitale Medien
    Digitale Medien
    Mitteilungen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1788-1789 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690737
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  • 190
    Digitale Medien
    Digitale Medien
    Masthead (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986) 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690801
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  • 191
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    Digitale Medien
    Membrane Structure of Substance P. I. Prediction of Preferred Conformation, Orientation, and Accumulation of Substance P on Lipid MembranesPeptide nomenclature and abbreviations, see IUPAC-IUB JBCN Recommendations 1983 on ‘Nomenclature and Symbolism for Amino Acids and Peptides’ [1a]. (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1789-1797 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Preferred conformation, orientation, and accumulation of substance P on a neutral hydrophilic-hydrophobic interface was estimated and extrapolated to interactions with neutral and anionic lipid bilayer membranes according to our general procedure. Nine residues at the C-terminus were predicted to be transferred to the hydrophobic phase as an α-helical domain, oriented quite perpendicularly on the membrane surface. The N-terminal residues remained in the aqueous phase with their charges exposed to H2O. The molecular amphiphilic moment vector was strong (338 arbitrary units) and pointed its hydrophilic end towards the N-terminus, only 15° away from the helix axis. The molecular electric dipole moment vector was also strong (124 debye) and pointed its positive end towards the N-terminus, only 9° away from the helix axis. Thus, it reinforced the effect of the amphiphilic moment of a peptide intruding into the membrane dipole layer. The estimated dissociation constant for the equilibrium between membrane-bound and free substance P was Kd ≍ 46 mM for neutral membranes, and Kd ≍0.43 mM for anionic membranes with a Gouy-Chapman surface potential of -40 mV. Thus, substance P behaved similarly to dynorphin A and adrenocorticotropin peptides which insert their N-terminal message segments as perpendicularly oriented helical domains into membranes, whereas their C-terminal address segments remain in the aqueous phase as random coils. Substance P is the first instance of a neuropeptide which is expected to insert a C-terminal message into lipid membranes.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690802
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  • 192
    Digitale Medien
    Digitale Medien
    Membrane Structure of Substance P. II. Secondary Structure of Substance P, [9-Leucine]substance P, and Shorter Segments in 2,2,2-Trifluoroethanol, Methanol, and on Liposomes Studied by Circular DichroismPeptide nomenclature and abbreviations, see IUPAC-IUB JBCN Recommendations 1983 on ‘Nomenclature and Symbolism for Amino Acids and Peptides’ [1a] and Table 1. Amino-acid residues are in their L-configuration unless explicitly stated otherwise. Random coil means nonregular, nonrepeating sequences of backbone dihedral angles with or without equilibria between various random coil conformers. PC = phosphatidyl-choline; DOPC = dioleoyl-sn-glycero-3-phosphocholine; PS = phosphatidylserine (brain). (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1798-1806 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Comparative CD studies with substance P (1), [Leu9]substance P ([Leu9]-1), and their shorter peptide segments supported the membrane structures predicted for substance P and [Leu9]substance P. They indicated that the C-terminal segments (from residue 3 or 4 onward) can adopt α-helical conformations in hydrophobic environments and on lipid membranes. The N-terminal segment, (residues 1-4) had a poly(proline)-like conformation in aqueous and hydrophobic surroundings. Residues 3 and 4 (Lys-Pro) appeared to belong to both domains and bring about the transition between the two. The estimated free energies of transfer for 1 and [Leu9]-1 from their random conformations in H2O to their partially helical conformations on an aqueous-hydrophobic interface are too small to allow detectable interaction with neutral lipid membranes at low concentrations. The two peptides should, however, interact detectably with anionic membranes because of favourable Boltzmann distribution factors. This prediction was shown to be correct for liposomes prepared from 1,2-dioleoyl-sn-glycero-3-phosphocholine (neutral) and phosphatidylserine (anionic).
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690803
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  • 193
    Digitale Medien
    Digitale Medien
    Membrane Structure of Substance P. III. Secondary Structure of Substance P in 2,2,2-Trifluoroethanol, Methanol, and on Flat Lipid Membranes Studied by Infrared SpectroscopyPeptide nomenclature and abbreviations, see IUPAC-IUB JBCN Recommendations 1983 on ‘Nomenclature and Symbolism for Amino Acids and Peptides’ [la] and Table 1. Amino-acid residues are in their L-configuration unless explicitly stated otherwise. Random coil means nonregular, nonrepeating sequences of backbone dihedral angles with or without equilibria between various random-coil conformers. IR-ATR = infrared attenuated total reflection spectroscopy. POPC = 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine. (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1807-1816 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: IR data of the neuropeptide substance P (1) and its synthetic segments des-(Arg1-Gln6)-substance P (6), des-(Arg1-Pro4)-substance P (4), des-(Arg1-Lys3)-substance P (3), and des-Arg1-substance P (2) indicate predominant β-structures in the solid state and α-helical structures in CF3CH2OH (amide I band shape analysis). In MeOH, the spectra of 1 suggest a partly helical structure. On membranes prepared from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, a C-terminal α-helix consisting of 8 or 9 peptide bonds appears to be induced (IR attenuated total reflection studies). Its perpendicular orientation on the membrane is suggested by the dichroic ratios of the amide-I and -II bands. This study is consistent with our CD experiments and lends support to the membrane structure of 1 predicted from the estimated amphiphilic moment, hydrophobic-association constant, and helix length.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690804
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  • 194
    Digitale Medien
    Digitale Medien
    Enantioselective Synthesis of β-Necrodol and of 1-Epi-β-necrodol via Asymmetric 1,4-Addition and Magnesium-Ene Cyclization. Preliminary Communication (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1817-1820 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Enantiomerically pure β-necrodol (1) and its 1-epimer 16 have been synthesized starting from aldehyde 5. The two key steps are an asymmetric conjugate addtion/Mannich reaction tandem (10→12) and a type-II-magnesiumene cyclization/oxidation sequence (14→1 + 16).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690805
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  • 195
    Digitale Medien
    Digitale Medien
    3,7-Dioxaazelaamides as Ionophores for Lithium Ion Selective Liquid Membrane Electrodes (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1821-1828 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Lipophilic neutral carriers were synthesized which show Li+/Na+ selectivities of up to ca. 80 in highly lipophilic liquid membranes. The sensor membranes exhibit improved response times and increased lifetimes as compared to systems described earlier. They allow reliable measurements of Li+ in blood serum within the clinical concentration range. A 1:1 Li+/ionophore complex of one representative (N,N,N′,N′-tetracyclohexyl-5,5-dimethyl-3,7-dioxaazelaamide) has been prepared, and its structure was elucidated by X-ray analysis.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690806
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  • 196
    Digitale Medien
    Digitale Medien
    Stoffwechselprodukte von Mikroorganismen. 237. Mitteilung236. Mitt.: [1]. (2S, 3R, 4R, 6R)-2,3,4-Trihydroxy-6-methylcyclohexanon aus zwei Actinomyceten-Stämmen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1829-1832 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: (2S, 3R, 4R, 6R)-2,3,4-Trihydroxy-6-methylcyclohexanone from Two Strains of ActinomycetesA tetrazolium-blue positive compound was isolated from two strains of acinomycetes. Its constitution and relative configuration 1 were determined by spectroscopic methods, and the absolute configuration by degradation to (+)-(R)-methylsuccinic acid.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690807
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  • 197
    Digitale Medien
    Digitale Medien
    Stoffwechselprodukte von mikroorganismen. 238. Mitteilung237. Mitt.: [1].. Isolierung und Strukturaufklärung von Differolid (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1833-1836 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Isolation and Structure Elucidation of DifferolideFrom cultures of a new actinomycete, Streptomyces aurantiogriseus (PREOBRAZHENSKAYA 1975), strain Tü 3149, a compound C12H12O4 was isolated, which enhances the formation of aerial mycelium and spores of Streptomyces glaucescens. The structure determined by X-ray diffraction studies was that of racemic dilactone 1 ((±)-differolide).
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690808
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  • 198
    Digitale Medien
    Digitale Medien
    Carbophile Additionen von Organocupraten mit 1,3-Thiazol-5(4H)-thionen (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1837-1843 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Carbophilic Additions of Organocuprates and 1,3-Thiazole-5(4H)-thionesOrganocuprates and 1,3-thiazole-5(4H)-thiones 1 react in THF at 0° via carbophilic addition onto the C—S bond to give 4,5-dihydro-1,3-thiazole-5-thiols 3 (Scheme 3). This observation is in marked contrast to the previously described reaction of organolithium compounds and 1, which undergo a thiophilic addition onto the exocyclic S-atom. As an exception, treatment of the 1,3-thiazole-5(4H)-thione 1a with tert-butyl cuprate leads to 7a (Scheme 3).
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690809
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  • 199
    Digitale Medien
    Digitale Medien
    Synthesis of 3β-Hydroxy[21-14C]-5β-pregn-8(14)-en-20-one from Chenodeoxycholic Acid (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1844-1850 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 3β-Hydroxy[21-14C]5β-pregn-8(14)-en-20-one (17) was prepared from chenodeoxycholic acid (1a). The synthetic sequence involved: (i) degradation of the bile-acid side chain to an etianic acid; (ii) formation of the 8(14)-double bond; (iii) inversion of the configuration at C(3); (iv) construction of the acetyl side chain at C(17) with the required isotopic label at C(21). Structures of all described products were confirmed by chemical and spectroscopic (IR, 1H-NMR, 13C-NMR, MS) methods.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690810
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  • 200
    Digitale Medien
    Digitale Medien
    Neue 1,6-Methano[10]annulen-Derivate durch Umlagerungsreaktionen der Trimethylsilyl-Gruppe (1986)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 69 (1986), S. 1851-1854 
    Details
    ISSN: 0018-019X
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: New Derivatives of 1,6-Methano[10]annulene by Rearrangement of Trimethylsilyl GroupsOxidation of derivatives of trimethylsilyl-substituted bicyclo[4.4.1]undeca-1,3,5,7-tetraenes 1-3 leads to 1,6-methano[10]annulenes. In the case of 2 and 3a, rearrangement of the trimethylsilyl group takes place. This rearrangement can be used to prepare 2,9-disubstituted 1,6-methano[10]annulenes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/hlca.19860690811
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