VILLIRAMULIN-A AND VILLIRAMULIN-B - NEW PHENOL DERIVATIVES FROM PIPER-VILLIRAMULUM

Two new phenol derivatives, villiramulin A (1) and B (2), have been isolated from the Panamanian plant Piper villiramulum and assigned structures on the basis of a variety of spectroscopic data. After a model study wherein the (+)- and (-)-O-methylmandelate esters of 2-heptanol were shown to present significantly different H-1 NMR spectra, villiramulin A was esterified with both of these acids. On the basis of the H-1 NMR data of the resulting esters, the S stereochemistry was assigned to the natural product. Finally, villiramulin B was shown to be significantly active in a bioassay that measures repellency to a captive colony of leafcutter ants.