Four mono-tetrahydrofuran ring acetogenins, montanacins B - E, from Annona montana

Abstract

Four novel mono-tetrahydrofuran (THF) acetogenins, montanacins B - E (1 - 4), were isolated from the ethanolic extract of the leaves of Annona montana. The structures of 1 - 4 were established by spectroscopic methods and their absolute stereochemistries were determined by the advanced Mosher ester method. Montancins D (3) and E (4) bear a non-adjacent tetrahydropyran (THP) ring along with a THF ring and are the most unusual type of acetogenins discovered so far.