摘要:

A twenty year investigation of the South African marine spongeSpirastrella spinispirulifera(Carter, 1879) for antineoplastic constituents has now led to discovery of spongistatin 6 (1e) and 7 (2b) in 3.5 × 10−7% and 2.2 × 10−7% yields. Structural elucidations were based on detailed analyses of high field (400 and 500 MHz) 2D-NMR and high resolution mass spectra. Spongistatins 6 and 7 were exceptionally potent against a subset of human cancer cell lines in the NCI screening panel which are characteristically sensitive to cellular microtubule interactive antimitotics.

ISSN:1057-5634    

DOI:10.1080/10575639308043871

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Cyathoviridine2was isolated from the bark ofCyathostemma viridiflorumGriff. and its structure elucidated by 2D NMR analysis.2showed cytotoxicity against KB cells (IC504.5 μ/ml).

ISSN:1057-5634    

DOI:10.1080/10575639308043872

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A stereoselective synthesis of two marine fatty acidsviz. 19-methyleicosa-5(Z), 9(Z)-dienoic acid (I) and 18-methyleicosa-5(Z), 9(Z)-dienoic acid (II) has been developed. The synthetic strategy was based on C‒C bond formationvia(Z)-selective Wittig olefination of the required synthons which in turn were prepared from readily available materials.

ISSN:1057-5634    

DOI:10.1080/10575639308043873

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Several methods2a-gare known for the enantioselective syntheses of (+)-vincamine [1*]#and (+)-apovincaminic acid esters [2*].

ISSN:1057-5634    

DOI:10.1080/10575639308043874

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Pamamycin-621 (II) was isolated from the mycelium ofStreptomyces aurantiacusIMET 43917 and characterized as a new macrodiolide antibiotic by MS, NMR and chemical degradation experiments.

ISSN:1057-5634    

DOI:10.1080/10575639308043875

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The structure of salacenonal, a novel and biogenetically important 29-nortriterpenoid isolated fromSalacia reticulatahas been established as 3-hydroxy-2-oxo-29-nor-D:A-friedo-oleana-3(4),20(30)-dien-24-al (1).

ISSN:1057-5634    

DOI:10.1080/10575639308043876

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Two new bisabolanes were isolated from the aerial parts ofMatricaria aureain addition to seven known compounds. Their structures were established by spectroscopic techniques.

ISSN:1057-5634    

DOI:10.1080/10575639308043877

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Four new alkaloids with an aspidofractinine skeleton, singapurensines A-D6-9, have been isolated fromKopsia singapurensis(Apocynaceae) and their structure elucidated by spectral methods. They all possess an oxygen bridge between C-3 and C-17.

ISSN:1057-5634    

DOI:10.1080/10575639308043878

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Kopsidine A4aand B4bwere synthesised from kopsingine N-oxide via a biomimetic Polonovski-Potier reaction. 1,4-Addition of CH3OH or C2H5OH on the intermediate iminium salts, followed by 1,2-addition of the C-17 hydroxyl function produced the expected alkaloids.

ISSN:1057-5634    

DOI:10.1080/10575639308043879

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Bipendensin (1), an unusual phenolic acetal, has been isolated from the sapwood ofAfzelia bipendensis.

ISSN:1057-5634    

DOI:10.1080/10575639308043880

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor