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A combination of NMR analysis and molecular mechanics calculations has succeeded in the determination of the stereostructure of flexible briarane diterpenoids. The molecular mechanics calculations ...

Piericidins C5 (1) and C6 (2), two new members of the piericidin family, were isolated from a Streptomyces sp. and a Nocardioides sp., together with known piericidins C1 (3), C2 (4), C3 (5), C4 (6), D1 (7), and A3 (8). The structures were determined on the basis of their spectroscopic data. Both new compounds inhibited cell division of fertilized starfish (Asterina pectinifera) eggs at the minimum inhibitory concentration of 0.09 microg/mL.

Three new macrolides, micromonospolides A–C, have been isolated from a new species of the genus Micromonospora and their structures were elucidated to be bafilomycin-type macrolides which have a 16-membered lactone ring on the basis of spectroscopic data. Micromonospolides A–C inhibited gastrulation of starfish embryos at minimum inhibitory concentrations of 0.010, 0.011 and 1.6 μg mL−1, respectively.

Two new halogenated briarane diterpenes, (-)-2-deacetyljunceellin (1) and (-)-3-deacetyljunceellin (2). and five known diterpenoids, junceellin, praelolide, junceellolide A. B. and D were isolated from the Papuan gorgonian coral Junceela fragilis. The structures of the new metabolites were determined by extensive 2D NMR experiments and by chemical conversion. The absolute configuration of 2 was determined through the 1 H NMR study of the corresponding ester with a newly developed chiral auxiliary 3a.

A new macrolide, micromonospolide A, was isolated from an undescribed actinomycete, Micromonospora sp., and its structure was elucidated to be a bafilomycin-type macrolide which has a 16-membered lactone ring on the basis of spectroscopic data. Micromonospolide A inhibited gastrulation of starfish embryos at a concentration of 10 ng/ml or greater.

Three new macrolides, micromonospolides A–C, have been isolated from a new species of the genus Micromonospora and their structures were elucidated to be bafilomycin-type macrolides which have a 16-membered lactone ring on the basis of spectroscopic data. Micromonospolides A–C inhibited gastrulation of starfish embryos at minimum inhibitory concentrations of 0.010, 0.011 and 1.6 μg mL−1, respectively.

A new macrolide, micromonospolide A, was isolated from an undescribed actinomycete, Micromonospora sp., and its structure was elucidated to be a bafilomycin-type macrolide which has a 16-membered lactone ring on the basis of spectroscopic data. Micromonospolide A inhibited gastrulation of starfish embryos at a concentration of 10 ng/ml or greater.

Two new halogenated briarane diterpenes, (-)-2-deacetyljunceellin (1) and (-)-3-deacetyljunceellin (2). and five known diterpenoids, junceellin, praelolide, junceellolide A. B. and D were isolated from the Papuan gorgonian coral Junceela fragilis. The structures of the new metabolites were determined by extensive 2D NMR experiments and by chemical conversion. The absolute configuration of 2 was determined through the 1 H NMR study of the corresponding ester with a newly developed chiral auxiliary 3a.

Two new beta-hydroxy acetamides, BE-52211 B and BE-52211 C, which were structural analogues of BE-52211, were obtained as an inseparable mixture from an actinomycete, Streptomyces sp. Their structures were elucidated on the basis of spectroscopic data. They inhibited cell division of starfish embryos at a concentration of 2.5 microg/mL or greater.

Five new sulfur-containing polybrominated bisindole (1∼5) were isolated from the red alga, Laurencia brongniartii, in addition to six related compounds (6∼11), which have been previously found in the Okinawan alga. The structures of these new bisindole metabolites were elucidated on the basis of spectroscopic studies, as well as X-Ray crystallographic analysis of 1.