摘要:

Andrographolide triacetate (2) is known to react with organic bases to yield 11, 13-diene (3) but its reaction with enzymes such as trypsin and protease yielded a novel 12, 14-diene (4). L-arginine has been found to mimick the enzyme reaction.

ISSN:1057-5634    

DOI:10.1080/10575639808048862

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

(3S)-3,7-Dimethyl-7-hydroxyoct-5-enyl-O-β-D-glucopyranoside (1) was isolated as aroma precursor of isomeric rose oxides (2a/b) from flowers ofRosa damascenaMill. the isolation was guided by the detection of rose oxide formation by GC and GC-MS analyses after acid-catalyzed hydrolyses of precursor fractions. the structure of 1 was confirmed by spectroscopic analysis and synthesis starting from (35)-citronellol (4).

ISSN:1057-5634    

DOI:10.1080/10575639808048863

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Streptomyces sp.HKI-0095 produces the unusual dioxotetrahydronaphthalene metabolite I displaying moderate antimicrobial activity against Bacillus subtilis ATCC 6633. the chemical constitution was settled by MS and NMR measurements.

ISSN:1057-5634    

DOI:10.1080/10575639808048864

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Two novel phenyl propanoids, 1a and 2a, were isolated from the aerial parts of Schkuhria schkuhrioides, along with several known metabolites.

ISSN:1057-5634    

DOI:10.1080/10575639808048865

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper describes an efficient synthetic route to pentalongin (1H-naphtho[2,3-c]pyran-5,10-dione), a naphthoquinoid isolated from the aerial parts ofMitracarpus scaber, and to the structurally-related compound psychorubrin(3-hydroxy-1H-3, 4-dihydronaphtho[2,3-c]pyran-5,10-dione).

ISSN:1057-5634    

DOI:10.1080/10575639808048866

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The natural polyketides secocurvularin (4), curvulin (5), and the corresponding carboxylic acids6and curvulinic acid (7) were prepared in four steps starting from known 3,5-dibenzyloxy phenylacetic acid (8). Key step is the hydrolysis of the ethyl esters4and5by esterase from hog liver.

ISSN:1057-5634    

DOI:10.1080/10575639808048867

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

–3-Hydroxy-5,6-epoxy-β-ionone (1) showing an inhibitory activity for lettuce seed germination was isolated from leaves ofAthyrium yokoscense.

ISSN:1057-5634    

DOI:10.1080/10575639808048868

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Two new clerodane furano-diterpenes, 9-methoxycarbonyl-15, 16-epoxy-cleroda-3, 13(16), 14-trien-2-one (cromiargyne-1a) and 7-acetoxy-9-methoxywrbonyl-15,16-expoxy-cleroda-3,13(16), 14-trien-2-one (7-acetoxy-cromiargyne –1b). were isolated from the bark ofCroton hemiargyreus(Euphorbiaceae). the structures of these compounds were elucidated by spectral analysis.

ISSN:1057-5634    

DOI:10.1080/10575639808048869

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The endemic South African marine pulmonate gastropodTrimusculus costatusyielded two labdane diterpenes, the known 6β,7a-diacetoxylab-8,13-dien-15-ol (1), and the new 2α,6β,7a-triacetoxylabda-8,13-dien-15-ol (2). Standard spectroscopic methods were used to establish the structures of these compounds which were both toxic toArtemia salinaand inhibited feeding of the predatory fishPomadasys commersonnii.

ISSN:1057-5634    

DOI:10.1080/10575639808048870

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Mactanamide (1), a new diketopiperazine containing the uncommon amino acid D-2,6-dihydroxyphenylalanine, has been isolated from the mycelium of an undescribed marine fungus of the genusAspergillus. the new fungal strain was obtained from the surface of the brown marine algaSargassumsp. collected near Mactan Island in the Philippines. the structure and absolute stereochemistry of1was determined by interpretation of spectral data, by comparison with model compounds, and by measurement of the CD spectra of its component amino acids.

ISSN:1057-5634    

DOI:10.1080/10575639808048871

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor