摘要:

A novel pregnane oligoglycoside viz. Indicusin (1) was isolated from CHCl3-EtOH (3:2) fraction ofHemidesmus indicusR Br. (family Asclepiadaceae). With the help of FABMS,1H NMR,13C NMR spectroscopy and chemical transformations, the structure of1was defined as 11α, 12β-di-O-acetyl-orgogenin-3-O-β-D-cymaropyranosyl (1→4)-O-β-D-cymaropyranosyl (1→4)-O-β-D-cymaropyranoside.

ISSN:1057-5634    

DOI:10.1080/10575639508044094

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Two novel triterpene glycosides, asteryunnanosides C (1) and D (2) were isolated fromAster yunnanensisFranch. On the basis of chemical degradation and spectroscopic data, including 2D NMR techniques, their structures were elucidated as 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside and 28-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside of 2α, 3β-dihydroxy-olean- 12-en-28-oic acid respectively.

ISSN:1057-5634    

DOI:10.1080/10575639508044095

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A new oleanane glycoside, named ranuncoside VII, was identified as 3-O-[α-L-arabinopyranosyl-(1→6)-β-D-glucopyranosyl]-13β,28-epoxyolean-11-ene-3β, 15α,16α,21β,22α-pentol by chemical and spectroscopic studies. The aglycone structure was confirmed by hemisynthesis from R1-barrigenol.

ISSN:1057-5634    

DOI:10.1080/10575639508044096

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

An unusual mode of reaction of hydroxylamine hydrochloride catalyzed by zinc acetate, involving nucleophilic attack upon the perezone1lband isoperezone quinone systems, with further dehydration to produce the corresponding amino derivatives2and5is described.

ISSN:1057-5634    

DOI:10.1080/10575639508044097

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Four 9,10-dihydrophenanthrene glucosides have been isolated fromJuncus effususand their structures confirmed on spectroscopic grounds and by semisynthesis. The results of a cytotoxic assay are also reported.

ISSN:1057-5634    

DOI:10.1080/10575639508044098

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Five alkaloids have been isolated and identified inNitraria billardierifrom Australia. They consist of schoberine1, nitraramine21-epinitraramine3, nitrarine4and 3-epinitrarine5. Complete assignment of their NMR spectra is presented.

ISSN:1057-5634    

DOI:10.1080/10575639508044099

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A new stereocontrolled synthesis of a series of polyenic ketones isolated from marine opisthobranchs, namely lignarenone A, lignarenone B and 3-methylnavenone B, is described, which uses the Suzuki reaction in the key step. Thus, the thallium-accelerated, palladium-catalyzed cross-coupling reactions of (E)-1-alkenylboronic acids and alkenyl iodides constitutes an efficient procedure for the preparation of alkyl-substituted polyenes with uniform configuration.

ISSN:1057-5634    

DOI:10.1080/10575639508044100

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Glaucanisin(1), a new adjacent bis-tetrahydrofuran acetogenin, was isolated together with a known compound, rolliniastatin-2(2)from the CH2Cl2extract ofAnnona glaucaseeds. NMR and mass spectroscopic methods were used for the structure elucidation of glaucanisin, through comparison with the spectral data of rolliniastatin-2 (= bullatacin).

ISSN:1057-5634    

DOI:10.1080/10575639508044101

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The immediate precursor for the semi-synthesis of taxol, 7-triethylsilylbaccatin III (6), has been prepared from 10-DAB (3) using a Bu4NBH4/ LiCl regioselective deacetylation as the key step.

ISSN:1057-5634    

DOI:10.1080/10575639508044102

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In an effort towards the development of a facile synthesis ofN-benzoyl-(2R,3S)-3-phenylisoserine (3), an important subunit of taxol known as the “taxolC-13 side chain”, which can easily be handled in large scale production as well as meet industrial safety requirements, we present here an efficient and inexpensive synthesis of the taxol side chain via a classical resolution technique. This synthesis represents the most practical preparation of the taxol side chain developed to date.

ISSN:1057-5634    

DOI:10.1080/10575639508044103

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor