Lappuse 1 no 35 rezultātiem
Three new indole alkaloids, named kopsihainins A-C (1-3), and two known compounds, kopsinine (4) and methyl demethoxycarbonylchanofruticosinate (5), were isolated from the stems of Kopsia hainanensis. Their structures were determined using extensive spectroscopic methods. The two main constituents 4
Two new monoterpene indole alkaloids, characterized by previously unencountered natural product skeletons, viz., arborisidine (1), incorporating indolizidine and cyclohexanone moieties fused to an indole unit, and arbornamine (2), incorporating an unprecedented 6/5/6/5/6 "arbornane" skeleton
Three new indole alkaloids (1-3), named grandilodines A-C, and five known ones were obtained from the Malayan Kopsia grandifolia. The structures were established using NMR and MS analyses and, in the case of 1 and 2, were confirmed by X-ray diffraction analyses. Alkaloids 1, 3, and lapidilectine B
A phytochemical investigation on the 90% ethanol aqueous extract of the aerial part of Kopsia arborea led to the isolation of three new monoterpenoid indole alkaloids, kopsiarborines A-C (1-3). The new structures were elucidated by using spectroscopic data (NMR, IR, UV, and MS). The
A new pentacyclic indole alkaloid, kopsiyunnanine E, was isolated from Yunnan Kopsia arborea, and its structure, which was inferred from spectroscopic data, was established by a 16-step asymmetric total synthesis that proved that the natural alkaloid was not enantiomerically pure.
A chemical investigation on the 80% EtOH extract of the aerial parts of Kopsia fruticosa led to five new indole alkaloids, kopsifolines G-K (1-5), and one known alkaloid, kopsifoline A (6). Structural elucidation of all the compounds were performed by spectral methods such as 1D and 2D (1H-1H COSY,
Nine new indole alkaloids, rhazinoline (1), 19(S)-methoxytubotaiwine (2), 19(R)-methoxytubotaiwine (3), kopsamidine A (4), kopsamidine B (5), kopsinidine A (6), kopsinidine B (7), paucidactine C (8), and pericine N-oxide (9), in addition to several recently reported novel indoles and 34 other known
Three new indole alkaloids, named kopsihainin D (1), kopsihainin E (2), and kopsihainin F (3), along with nine known compounds (4-12) were isolated from the twigs of Kopsia hainanensis. The structures of the new compounds were elucidated by spectroscopic methods including HRESIMS, UV, IR, and NMR.
Three new alkaloids were isolated from the bark extract of the Malayan Kopsia arborea, viz., arbophyllidine (1), an unusual pentacyclic, monoterpenoid indole characterized by an absence of oxygen atoms and incorporating a new carbon-nitrogen skeleton, and arbophyllinines A (2)
The phytochemistry of Kopsia arborea Blume has received considerable attention, which has resulted in the isolation of a number of new unusual indole alkaloids with intriguing structures. In this study, a new eburnane-type alkaloid, phutdonginin (1), together with eight known alkaloids: 19-OH-(-)-
Two new indole alkaloids, kopsiyunnanines J1 and J2, were isolated from Yunnan Kopsia arborea, and their structures were determined by spectroscopic analyses. Kopsiyunnanines J1 and J2 are unprecedented Strychnos-type indole alkaloids having an additional C1 unit in the secologanin moiety of the
Two new indole alkaloids, kopsiyunnanines G (1) and H (2), possessing the Aspidosperma skeleton were isolated from the aerial part of Yunnan Kopsia arborea BLUME (Apocynaceae). Their structures and stereochemistry were elucidated by means of MS and 2D NMR analyses.
The tryptamine-derived polycyclic bridged bioactive indole alkaloids subincanadines A-G were isolated in 2002 by Ohsaki and coworkers from the bark of the Brazilian medicinal plant Aspidosperma subincanum. Kobayashi proposed that subincanadines D-F could be biosynthetically resulting from
[structure: see text] A new indole alkaloid, arboflorine, possessing a novel pentacyclic carbon skeleton and incorporating a third nitrogen atom was obtained from the Malayan Kopsia arborea. The structure was established by spectroscopic analysis, and a possible biogenetic pathway from a
A new monoterpenoid indole alkaloid, kopsiyunnanine K, was isolated from Kopsia arborea. Its intriguing rearranged structure and absolute configuration, which were inferred from spectral data and a possible biosynthetic pathway, were determined on the basis of a 13-step asymmetric total synthesis.