摘要:

AbstractPatchoulol(1)forms 2,2,6,8‐tetramethylbicyclo [5.3.1]undec‐7‐en‐3‐one(5)with lead tetraacetate. This ketone undergoes acid‐catalyzed cyclization to 2,6,6,10‐tetramethyltricyclo [5.3.1.01,5]undec‐9‐en‐5‐ol(10), and is reduced to 2 stereoisomeric alcohols with lithium aluminium hydride. One of these alcohols8is readily dehydrated with cyclization to 2,6,6,10‐tetramethyltricyclo [5.3.1.01,5]undec‐9‐ene(12)and a double bond isomer13, longer treatment with acid resulting in aWagner‐Meerweinrearrangement to a mixture of two 1,3,7,7‐tetramethyltricyclo [6.2.1.02,6]‐undecenes (19and20), isomeric with β‐patchoulene (23). The other alcohol7withp‐toluenesulfonic acid forms the cyclic ether, 1,3,7,7‐tetramethyl

ISSN:0018-019X    

DOI:10.1002/hlca.19790620202

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractStereospecific syntheses of (E)‐ and (Z)‐α‐bisabolenes have made revision of the configuration of natural (+)‐α‐bisabolene fromOpoponaxoil necessary.13C‐NMR. spectroscopy has been used for the differentiation of

ISSN:0018-019X    

DOI:10.1002/hlca.19790620203

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Concerning the preparation of methyl α‐D‐fructopyranoside and the structure of the orthoester by‐productsKoenigs‐Knorrglycosidation (AgClO4/Ag2CO3) of the easily accessiblep‐nitrobenzoylated fructosylchloride7yields mainly the protected glycoside3which was deacylated to the known title compound1. The orthoesters15and16were formed as by‐products in this glycosidation whilst the analogous orthoesters21and22are formed as main products in the glycosidation (Ag2CO3) of the benzoylated fructosylchloride12. The structure of these orthoesters was deduced mainly from their spectroscopic data, from those of their derivatives17,18,19,20,25and26and by comparison of the latter with the model comp

ISSN:0018-019X    

DOI:10.1002/hlca.19790620204

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Some Irradiation Experiments with 2, 1‐Benzisothiazoles2, 1‐Benzisothiazole (1) on irradiation with a mercury high‐pressure lamp in benzene/diethylamine yields, after acetylation, 2‐acetylamino‐benzaldehyde (3;Scheme 1). Similarly, irradiation of 3‐chloro‐2, 1‐benzisothiazole (2) in benzene/diethylamine leads to a mixture of 3‐dimethylamino‐2, 1‐benzisothiazole (6a) andN,N‐diethyl‐thioanthranilamide (7a;Scheme 2). Benzisothiazole6a, on irradiation, is not transformed into7a. On the other hand, when2is irradiated in methanol a mixture of 3‐methoxy‐2, 1‐benzisothiazole (4a) and methyl anthranilate (5a;Scheme 2) is obtained. In this case,4aon irradiation in methanol or ethanol also yields5a. No exchange of the methoxy group in4ais observed when the irradiation is performed in ethanolic solution. Thus, 2, 1‐benzisothiazoles1,2and4areact photochemically byN,S‐bond cleavage and hydrogen‐atom abstraction from the solvent (Scheme 3). 3‐Chloro‐2, 1‐benzisothiazole (2) shows a second photoreaction,i.e.nucleophilic exchange of the chloro substituent by methanol or diethyl amine. The latter reaction can also be observed thermally,e.g.in boiling

ISSN:0018-019X    

DOI:10.1002/hlca.19790620205

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractThe synthesis and biological testing of analogues of Met‐enkephalin, a recently discovered opioid peptide from mammalian brain, are described. Testing involved determination of affinity constants for an opiate receptor site and of analgesic potency in the tail‐flick test in mouse. The effects on opioid activity of modifying various parts of the enkephalin molecule are discussed. Tyr‐D‐Ala‐Gly‐MePheMet (O)‐olThe ending ‐ol added to the symbol of an amino acid designates the aminoalcohol obtained by reduction of the α‐carboxyl group of the amino acid.(FK 33‐824), which was highly active in these tests, was subsequently selected for clinical testing.The use of two complementary models ‐in vitrobinding studies andin vivotest for analgesia ‐ for the assessment of biological activity in the evaluation o

ISSN:0018-019X    

DOI:10.1002/hlca.19790620206

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractAus den oberirdischen Teilen der Seidenpflanze,Asclepias syriacaL.(Asclepiadaceae) isoliertenMasler et al.[2] [3]fünf krist. Cardenolide, u. a. Syriobiosid und Syriosid, denen sie die Formeln5und6zuschrieben.A. syriacaist eine der Futterpflanzen, auf denen die Larven von Schmetterlingen leben, welche die Cardenolide der Nahrung zu speichern vermögen und dadurch von der Vertilgung durch insektenfressende Tiere (bes. Vögel) teilweise geschützt sind. Die Inhaltsstoffe der Pflanze variieren stark. Bei dem uns zur Verfügung stehenden Material enthielten Blätter und Stengel nur Spuren von Cardenoliden, relativ viel enthielten die Wurzeln. Aus solchen konnte krist. Syriosid sowie eine Spur krist. Syriobiosid direkt durch Chromatographie gewonnen werden, die Hauptmenge des letzteren wurde erst nach fermentativem Abbau mit β‐Glucosidasen erhalten. Chemische und physikalische Methoden zeigten, dass die vorgeschlagenen Formeln5und6unrichtig sind. Syriobiosid besitzt vermutlich Formel7und Syriosid Formel10. Letzteres liefert bei fermentativem Abbau mit β‐Glucosidasen nicht Syriobiosid, wie die tschechischen Autoren glaubten, sondern einen um zwei H‐Atome ärmeren Stoff, den wir Desglucosyriosid (12) nennen. Die Formeln sind gut begründet, aber nicht eindeutig bewiesen. Syriosid und Syriobiosid enthalten somit als Zuckerbaustein eine 4,6‐Didesoxy‐hexosulose (33), wie sie im Gomphosid (20) und denCalotropis‐Cardenoliden (22,24etc.) vorkommt, die ebenfalls von den Larven der genannten Schmetterlinge mit der Nahrung aufgenommen werden und als Abwe

ISSN:0018-019X    

DOI:10.1002/hlca.19790620207

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Abstract3,4‐Dichlorobutanone reacts with trialkyl phosphites to give dialkyl 1,3‐butadien‐2‐yl phosphates. Their structures were determined by spectroscopic methods and various chemical re

ISSN:0018-019X    

DOI:10.1002/hlca.19790620208

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractExperimental investigations on the cosurfactant effect of alkali and tetraalkylammonium choleates in water/AOT/cyclohexane (W/O)‐microemulsions were carried out. The results prompted considerations on a thermodynamic and molecular level. The molecular view emphasizes the significance of hydration interactions between cosurfactant and solubilized wate

ISSN:0018-019X    

DOI:10.1002/hlca.19790620209

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Total Synthesis of Natural α‐Tocopherol. I. Preparation of Bifunctional Optically Active Precursors for the Synthesis of the Side Chain by Means of Microbiological TransformationsOur concept for a new total synthesis of natural α‐tocopherol includes the synthesis of a corresponding (3R, 7R)‐configurated C15side chain to be built up by using twice an optically active C5unit together with an achiral C5end part. (S)‐3‐methyl‐γ‐butyrolactone (11) and (S)‐2‐methyl‐γ‐butyrolactone (9) represent suitable bifunctional C5‐precursors for this purpose. These two key compounds have been prepared by fermentative transformation including the enantioselective hydrogenation of the double bond of ethyl‐4, 4‐dimethoxy‐3‐methylcrotonate (5) by bakers yeast (yielding11after ester hydrolysis and cyclization of the fermentation product) and (E)‐3‐(1′, 3′‐dioxolan‐2′‐yl)‐2‐buten‐1‐

ISSN:0018-019X    

DOI:10.1002/hlca.19790620210

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

Total Synthesis of Natural α‐TocopherolA short and efficient route to optically pure (+)‐(3R, 7R)‐trimethyldodecanol (14) is demonstrated,14serving as side chain unit in the preparation of natural vitamin E. The synthesis of14is based on the concept of using asingleoptically active C5‐synthon of suitable configuration and functionalization to introducebothasymmetric centres in14. (−)‐(S)‐3‐Methyl‐γ‐butyrolacton (1) and ethyl (−)‐(S)‐4‐bromo‐3‐methylbutyrate (2), respectively, is used in a sequence of either twoGrignardC,C‐coupling reactions5 → 8and12 → 13or twoWittigreactions17a → 18and20 → 21to achieve this goal.14is converted to (2R, 4′R, 8′R)‐α‐tocopherol (= vitamin E) by coupling with a chroman unit in known manner. Optical

ISSN:0018-019X    

DOI:10.1002/hlca.19790620211

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY