The effect of metal complexation on the antimicrobial activity of 1,4-naphthoquinones was investigated. Nickel-, chromium-, iron-, copper-, and cobalt-containing metal chelates of 5-amino-8hydroxy-1,4-naphtoquinone (2) and its acyl-derivatives (3-8) were synthesized and characterized, and their antimicrobial activity was evaluated. Data from infrared spectroscopy indicate that naphthoquinones c...

3-Amino-3-thioxopropanamide (1) reacted with ethyl acetoacetate to form 6-hydroxy-4-methyl-2-thioxo-2,3-dihydropyridine-3-carboxamide (2), which reacted with α-haloketones 3 to produce 2,3-disubstituted-8-hydroxy-6-methyl-2H,5H-pyrido[3,2-f]-[1,4]thiazepin-5-ones 4a-c. Benzoylation of 4c led to the formation of the dibenzoate derivative 9. Compounds 4a-c could be prepared stepwise through the f...

1. The variation with pH of the excitation and fluorescence wavelengths and fluorescence intensity of several hydroxy- and amino-biphenyls has been investigated with a view to using the data for the determination of hydroxybiphenyls in biological material. 2. 2- and 3-Hydroxy-, 2,2'-dihydroxy-, and 2-, 3- and 4-amino-biphenyl exhibited excited-state ionization. 4-Hydroxy- and 4,4'-dihydroxybiph...

(14R)-14-Hydroxy-6-O-methylerythromycin A and (14S)-epimer have been isolated as active metabolites from human urine after oral administration of 6-O-methylerythromycin A (TE-031, A-56268). The structures of these metabolites were determined by means of mass, 1H and 13C NMR spectroscopies. Antimicrobial activities of (14R)-14-hydroxy-6-O-methylerythromycin A, a major metabolite, were comparable...

Two new compounds, fumitremorgin 12-methoxy-13-[5'-hydroxy-2'-(1''-hydroxy-3''-methoxy-5''-methylbenzoyl)-3'-methoxy]benzoic acid methyl ester (fumitremorgin D, 1) and 4,8,10,14-tetramethyl-6-acetoxy-14-[16-acetoxy-19-(20,21-dimethyl)-18-ene]-phenanthrene-1-ene-3,7-dione (2) were isolated from the cultured endophytic isolated fungus Aspergillus fumigatus, together with fourteen known compounds....

High-yielding strains of Claviceps purpurea (Fr.) Tul, grown on a defined medium, have been used for a study of the biosynthesis of the peptide ergot alkaloid, ergotamine. l-[U-(14)C]tryptophan, dl-[2-(14)C]mevalonic acid lactone, sodium [2-(14)C]acetate, sodium [(14)C]formate and the methyl group of l-[methyl-(14)C]methionine were efficiently incorporated into the peptide alkaloids and specifi...

A small-scale synthesis of the four sphingosine stereoisomers (d-erythro, l-erythro, d-threo, and l-threo) and lignoceroyl d- and l-erythro-sphingosines, which is suitable for synthesis of tritium-labeled compounds, is described. Ethyl dl-erythro-2-acetamino-3-hydroxy-4t-octadecenoate was esterified with l(+)-acetylmandeloyl chloride and the two diastereomers obtained were separated from each o...