Showing papers by "Xiang-Hai Cai published in 2007"
TL;DR: A pair of geometrically isomeric monoterpenoid indole alkaloids with a skeleton rearrangement and two additional carbons were obtained from the leaf extract of Alstonia scholaris and their structures were elucidated on the basis of spectroscopic methods and then confirmed by X-ray crystal diffraction.
113 citations
TL;DR: Three new alkaloids are identified from the roots of Stemona mairei (levl.) Krause and the structures were elucidated by a combination of 1D, 2D-NMR, and mass spectral techniques.
Abstract: Three new alkaloids, maireistemoninol (1), neotuberostemonone (2) and epoxytuberostemonone (3), together with six known alkaloids, neotuberostemoninol (4), neotuberostemonine (5), bisdehydroneotuberostemonine (6), bisdehydrotuberostemonine (7), 2-oxostenine (8), and stemotinine (9), were isolated from the roots of Stemona mairei (levl.) Krause. The structures were elucidated by a combination of 1D, 2D-NMR, and mass spectral techniques.
13 citations
TL;DR: A pair of geometrically isomeric monoterpenoid indole alkaloids with a skeleton rearrangement and two additional carbons, named (19,20) E-alstoscholarine (1) and (19.20) Z-alstonia scholaris (2), were obtained from the leaf extract of Alstonia and their structures were elucidated on the basis of spectroscopic methods and then confirmed by X-ray crystal diffraction as mentioned in this paper.
Abstract: A pair of geometrically isomeric monoterpenoid indole alkaloids with a skeleton rearrangement and two additional carbons, named (19,20) E-alstoscholarine (1) and (19,20) Z-alstoscholarine (2), were obtained from the leaf extract of Alstonia scholaris. Their structures were elucidated on the basis of spectroscopic methods and then confirmed by X-ray crystal diffraction. The biogenesis of these compounds was also proposed.
10 citations
TL;DR: In this article, four new tirucallane triterpenoid saponins, named munronosides I-IV (2-5), along with three known triterbenoids, sapelin B (1), melianodiol.
Abstract: Four new tirucallane triterpenoid saponins, named munronosides I-IV (2-5). along with three known triterpenoids, sapelin B (1). melianodiol. and (3 beta)-22,23-epoxytirucall-7-ene-3,24,25-triol, were isolated from the EtOH extract of the whole plants of Munronia delavayi FRANCH by chromatographic methods. On the basis of spectroscopic evidences, the structures of 2-5 were elucidated as (20S,23R,24S)-21,25-epoxy-29-{{O-beta-D-glucopyranosyl-(1 -> 3)-O-[alpha-L-rhamnopyranosyl-(1 -> 6)]-beta-D-glucopyranosyl}oxy}-23,24-dihydroxytirucall-7-ene-3,21-dione (2), (3 beta,20S,23R,24S)-21,25-epoxy-29-{{O-beta-D-glucopyranosyl-(1 -> 3)-O-[alpha-L-rhamnopyranosyl-(1 -> 6)]-beta-D-glucopyranosyl}oxy}-3,23,24-trihydroxytirucall-7-en-21-one (3), (20S,23R,24S)-24-(acetyloxy)-21,25-epoxy-29-{{O-beta-D-glucopyranosyl-(1 -> 3)-O-[alpha-L-rhamnopyranosyl-(1 -> 6)]-beta-D-glucopyranosyl}oxy}-23-hydroxytirucall-7-ene-3,21-dione (4), and (3 beta,20S,23R,24S)-24-(acetyloxy)-21,25-epoxy-29-{{O-beta-D-glucopyranosyl-(1 -> 3)-O-[alpha-L-rhamnopyranosyl-(1 -> 6)]-beta-D-glucopyranosyl}oxy}-3,23-dihydroxytirucall-7-en-21-one (5).
8 citations