RESUMEN
In this study, in situ catalytically generated allylic indium from 1,3 dienes and InCl2H was developed for use in the allylation of ketones. This protocol resulted in the unprecedented establishment of a successive combining of quaternary C-C bonds, which could then be applied to many types of ketones. Other branched 1,3 dienes and vinyl cyclopropanes, could also be coupled with ketones in a reaction where CuH would not be applicable.
RESUMEN
The polyphenolic composition of Camellia irrawadiensis, which is a closely related species of Camellia sinensis (cultivated tea), was investigated. The most predominant polyphenol, a kind of ellagitannin, was isolated from leaves of C. irrawadiensis. Its structure was established as 1,2-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-beta-D-glucose (2) on the basis of spectral and chemical evidence. Moreover, the polyphenols [catechins, strictinin (1), compound 2, theogallin, and gallic acid] and two methylxanthines (theobromine and caffeine) in leaves of C. irrawadiensis were determined by HPLC-Photodiode array detector analysis, and were compared to those in C. sinensis and Camellia taliensis. Total catechin content in C. irrawadiensis was lower than that in C. sinensis and C. taliensis. Theobromine content in C. irrawadiensis was higher than that in C. sinensis and C. taliensis. The content of 2 in C. irrawadiensis was 8.4% of dry leaf weight and comprised approximately 60% of the total polyphenols detected, while the compound was not detected in C. sinensis and was reported to be 2.4% in C. taliensis.
Asunto(s)
Camellia/química , Flavonoides/análisis , Flavonoides/química , Fenoles/análisis , Fenoles/química , Hojas de la Planta/química , Flavonoides/aislamiento & purificación , Conformación Molecular , Fenoles/aislamiento & purificación , Polifenoles , Especificidad de la EspecieRESUMEN
To clarify the biosynthetic pathway to 2-phenylethanol (2), the deuterium-labeled putative precursor, [2H8]L-phenylalanine ([2H8-1]), was fed to the flowers of Rosa 'Hoh-Jun' and R. damascena Mill. throughout maturation, ceasing feeding at the commencement of petal unfurling and at full bloom. Based on GC-MS analyses, [2H8]-1 was incorporated into both 2 and 2-phenylethyl beta-D-glucopyranoside (3) when the flowers were fed until full bloom, whereas no such incorporation into 2 was apparent when feeding was ceased earlier. In both species of rose, the labeling pattern for 2 was almost identical to that for 3, and indicated the presence of [2H6]-, [2H7]- and [2H8]-2, and [2H6]-, [2H7]- and [2H8]-3. This may be ascribed to the equilibrium between 2 and 3. The labeling pattern for 2 and 3 also indicated that these compounds were produced from 1 via several routes, the route involving phenylpyruvic acid being the major one.