Further guaianolides from Amphoricarpos neumayeri ssp murbeckii from Montenegro

Abstract

The aerial parts of Amphoricarpos neumayeri ssp. murbeckii afforded eleven guaianolides with the same relative (1 alpha H,4 beta H,5 alpha H, 7 alpha H) configuration of the basic skeleton. All of them contained a CH2OX (X = H, acetyl or isovaleroyl) group in 4 alpha-position, typical for amphoricarpolides. Four compounds (1-4) were isolated before from the same species, originating from different localities. Guaianolides 5-11 are new compounds. Compounds 7 and 8 were epoxidized at the 10 alpha(14)-position. Instead of the Delta(11(13))-double bond, observed in all previously isolated guaianolides from the same species, the four lactones contained 11 alpha,13-diol (8-10) or 11 alpha-OH, 13-chloro (11) moieties respectively.