ANNONACEOUS ACETOGENINS FROM THE SEEDS OF ANNONA-SQUAMOSA - ADJACENT BIS-TETRAHYDROFURANIC ACETOGENINS

The petroleum ether extract of the seeds of Annona squamosa L. yielded thirteen adjacent and four non-adjacent bis-tetrahydrofuranic acetogenins, in addition to squamocin (1) and squamostatin-A. The structures of the thirteen acetogenins, named as squamocins-B (2), -C (3), -D (4), -E (5), -F (6), -G (7), -H (8), -I (9), -J (10), -K (11), -L (12), -M (13) and -N (14), have been established on the basis of spectral evidence. Squamocins-B, -D, -E, -F, -I, -K and -N are new acetogenins. The structures of these acetogenins vary in the carbon number (C,, or C,,), the number and position of hydroxyl groups (substituted at C-4, C-12, C-28 or C-29) and the stereochemistry at the histetrahydrofuran moiety. Squamocin-N (14) has an unprecedented threo-cis-threo-cis-threo eo stereochemistry in its bis-tetrahydrofuran portion. Co-occurrence of a diastereoisomeric pair, 9 and 10, is noteworthy.