Studies on Terpenoids Produced by Actinomycetes : Oxaloterpins A, B, C, D, and E, Diterpenes from Streptomyces sp. KO-3988

Following screening for terpenoids produced by Streptomyces sp. KO-3988, five new diterpenes named oxaloterpins A (1), B (2), C (3), D (4), and E (5) together with the known viguiepinone (6) were isolated from culture broth, and their structures were established on the basis of extensive NMR and MS analyses. The absolute configuration of oxaloterpin A was determined by the modified Mosher’s method as 3R, 5S, 8S, 10R, 13S.