MINOR COUMARINS FROM CALOPHYLLUM-TEYSMANNII VAR. INOPHYLLOIDE AND SYNTHESIS OF CYTOTOXIC CALANONE DERIVATIVES

A chemotaxonomic survey for biologically active compounds from Malaysi an Calophyllum species led to the finding of the four new benzoylcouma rins 1a, 2, 3, and 4a (including the unusual prenylated 6-benzoylcouma rin la), two uncommon coumarins 5 and 6a with a pyran-4-one moiety fus ed at C(6) and C(7), and compounds 7a, 9, and 10, all isolated from th e bark of C. teysmannii var, inophylloide. Their structures were deter mined by spectroscopic analysis and chemical transformations. X-Ray cr ystal-structure determination of 2 provided information on the conform ational preferences of substituents in this class of coumarins. The sy ntheses of the cytotoxic calanone (7a) and of some related coumarins a re described.