摘要:

AbstractThe title compounds (E/Z)‐7were prepared in 66% overall yield by reaction of β‐ionone ((E)‐(1) with lithium dimethylcuprate, trapping of the intermediate enolate with benzeneselenenyl bromide and oxidation with H2O2. Analogously, (E/Z)‐7‐methyl‐α‐inone ((E/Z)‐12) was obtained in 65% yield from α‐ionone ((E)‐11).1n, π*‐ Excitation (λ>347 nm, pentane) of (E)‐7 causes rapid (E/Z)‐isomerization and subsequent reaction of (Z)‐7to15(66%). The formation of15is explained by twisting of the dienone chromophore due to repulsive interaction of the 7‐CH3‐group with the CH3‐groups of the cyclohexene ring. On the other hand, irradiation λ>347 nm, Et2O) of (E)‐7in the presence of acid leads to (

ISSN:0018-019X    

DOI:10.1002/hlca.19840670502

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractThe occurrence of a series of new constituents which can be considered asDiels‐Alderadducts of methyl vinyl ketone and ocimene (→1–4), myrcene (→9,10) or β‐far‐nesene ( →11,12), respectively, was reported. Furthermore, the structures of four isomeric cyclohexene derivatives could be established as adducts21–24of (E, Z)‐ and (E, E)‐1,3,5‐undecatrience and methyl vinyl ketone. Another series of constituents having the norbornane skeleton represents adducts25–32, and33–40of methyl cyclopentadiene and 1‐octen‐3‐one or methyl vinyl ketone, respectively. In accordance withAlder'sendo‐rule theendo‐isomers are preponderant in the natural as well as in the synthetic mixtures. Most of these constituents could also be identified in a lavender absolute as well as in a freshly prepared hexane extract of lavender

ISSN:0018-019X    

DOI:10.1002/hlca.19840670503

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

Abstract(5R*,9S*)‐ and (5R*,9R*)‐2,2,9‐Trimethyl‐1,6‐dioxaspiro [4.4]non‐3‐ene (1aand1bresp.) and their dihydro derivatives2aand2bare described as new constituents of geranium oil. The structures and configurations of1a,1b,2a, and2b, are based on spectra interpretation and syntheses. Also some other monoterpenoid constituents identified in the same boiling range

ISSN:0018-019X    

DOI:10.1002/hlca.19840670504

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractA novel cyclopentenone ring annelation reaction is described. The treatment of the nitro compound13with aqueous sodium hydroxide in the presence of a phase‐transfer catalyst furnished14ain one step. Similar treatment of7led to8, the reaction of which witht‐BuOK afforded9awithout purification in high yi

ISSN:0018-019X    

DOI:10.1002/hlca.19840670505

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

Isolation and Structure of Rutamycin BBotrycidin was found to be identical with rutamycin. From the cultures of the actinomycete producing botrycidin and the venturicidines. A and B, a fourth antifungal antibiotic, rutamycin B, was isolated. Through a series of degradation products its structure could be correlated to that of rutamycin, which had been determined before by an X‐ray structural analysis. RutamycinBhas been identified as 12‐deocy‐ruta

ISSN:0018-019X    

DOI:10.1002/hlca.19840670506

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractThe substituted 1,2,3,4,4a,9,10,10a‐octahydrophenanthrene‐4,9‐dione2, synthesized from the cyclohexanone8and quinone11(Scheme 2), was found by X‐ray analysis adn1H‐NMR studies to be the isomer withcis‐junction of the saturated rings. Thecis‐fusion could also be determined from the1H‐NMR data of the related compound17(Scheme 4), which was previously considered to betrans‐fused. In contrary to previous argumentations, the interaction of the C(4)‐carbonyl O‐atom oftrans‐fused octahydrophenanthenes is more severe with a 5‐methoxy than wi

ISSN:0018-019X    

DOI:10.1002/hlca.19840670507

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractGas phase emission and laser excitation spectra of the Ã2E↔X̃2E (Σ = +½, −½) transition of rotationally/vibrationally cooled 1‐chloro‐ and 1‐bromo‐1,3‐pentadiyne cations have been obtained. The emission was excited by electron impact on a seeded helium supersonic free jet and the fluorescence by laser excitation of cations produced byPenningionization and collisional relaxation. From these two sets of data the origin bands of the spin‐orbit systems are located and for the bromo species this leads to better values of the spin‐orbit splitttings in the two electronic states and of the first adiabatic ionization energy. The vibrational frequencies of many of the fundamentals of these cations in the X̃2E and Ã2E states have been ob

ISSN:0018-019X    

DOI:10.1002/hlca.19840670508

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractThe13C‐NMR spectra of eight semi‐synthetic side‐chain substituted cannabinoids and of eight synthetic intermediates were analyzed in detail. Assignments of the signals are based on their chemical shifts, splitting patterns in1H‐off‐resonance decoupling experiments, incremental calculations, and model consi

ISSN:0018-019X    

DOI:10.1002/hlca.19840670509

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

On the Mechanism of the Aziridine Synthesis from 2‐Azido‐alcohols and TriphenylphosphineThe reaction of selected 2‐azido‐alcohols, their pivalates, and methanesulfonates with triphenylphosphine was investigated. It is shown that the formation of aziridines from 2‐azido‐alcohols proceedsvia1,3,2λ5oxazaphospholidines. Furthermore, the first synthesis of the unsubstituted acenaphtene‐1,2‐im

ISSN:0018-019X    

DOI:10.1002/hlca.19840670510

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractAuthentic α‐santolinenone ( = (+)‐(4R)‐1(7)‐p‐menthen‐2‐one; (+)‐1) is made available for the the first time in 30% overall yield from (+)‐(4R)‐p‐menthene ((+)‐2)viathe diastereoisomeric allylic alcohols (+)‐4a/(+)‐4b, which are oxidized to (+)‐1with Ag2CO3/Celite. Yields are good, except for the last stage; indeed, only alcohol (+)‐4a, with equatorial OH‐group, undergoes oxidation, and (+)‐1is partly substractedviaa heteroDiels‐Alderdimerization giving a mixture of the diastereoisomeric dihydropyrans (+)‐5a/(+)‐5b. When Cr(VI) reagents ae used, (+)‐4a/(+)‐4bmainly give phellandral (6) and carvotanacetone (7), NnO2reacts too sluggishly with (+)‐4a/(+)‐4b. A camphor pyrolyzate, previously tho

ISSN:0018-019X    

DOI:10.1002/hlca.19840670511

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY