Stereochemistry of 14-hydroxy-β-caryophyllene and related compounds
作者:Alejandro F. Barrero、José Molina、J. Enrique Oltra、Joaquín Altarejos、Armando Barragán、Armando Lara、Margot Segura
DOI:10.1016/0040-4020(95)00104-g
日期:1995.3
The isomerization of beta-caryophyllene (3), under treatment with SeO2, is described. Chemical correlations, between 3 and 14-hydroxy-beta-caryophyllene (6) from Juniperus oxycedrus, are established. High resolution H-1 NMR spectra and analysis by molecular mechanics of 3, 6 and 14-acetoxy-beta-taryophyllene (1) indicate the existence of two conformational isomers, beta alpha and beta beta, in each compound. At 25 degrees C, the beta alpha conformer predominates in 3 and 7 but the beta beta conformer predominates in 6. The higher percentage of 6 beta beta possibly derives from an intramolecular hydrogen bond. The treatment of 3, 6 and 7 with m-CPBA generates, in each case, two diastereomeric 4,5-epoxi-derivatives. The epoxides obtained from 6 have been isolated and analysed separately.
Betulenols from Betula Species
作者:Betül Demirci、K. Hüsnü Can Başer*、Temel Özek、Fatih Demirci
DOI:10.1055/s-2000-8591
日期:2000.6
The essential oils from buds of five Betula species growing in Turkey were investigated by GC-MS. A major component in the essential oils was shown to be 14-hydroxy-β-caryophyllene (6). The structure of β-betulenal (12) which was isolated from Betula essential oils was also confirmed by synthesis. Chemical reactions yielded 14-acetoxy-β-caryophyllene (15), 14-hydroxy-isocaryophyllene (10) and its acetate (14), giving evidence to the natural occurrence in Betula species of the formerly known α-betulenol acetate (3), β-betulenol (2) and β-betulenol acetate (4), respectively. Compounds 6, 9, 10, 12, and 15 were evaluated for antimicrobial activity.
SELECTIVE OXIDATION OF ALLYLIC METHYLS IN MEDIUM RING COMPOUNDS
作者:Baldev R. Chhabra、Kiyoharu Hayano、Toshikazu Ohtsuka、Haruhisa Shirahama、Takeshi Matsumoto
DOI:10.1246/cl.1981.1703
日期:1981.12.5
Allylic methyls in medium ring compounds were selectively oxidized to primary alcohols and αβ-unsaturated aldehydes by means of t-butylhydroperoxide and selenium dioxide supported on silica gel.