Unusual natural 9,10-dihydrophenanthrenes from roots of Toona ciliata

Abstract

The roots of Toona ciliata yielded four new 9,10-dihydrophenanthrenes which were identified on the basis of spectroscopic analysis as 9,10-dihydro-9-hydroxy-9-(tert-butoxycarbonylmethyl)-10-oxophenanthrene, 9,10-dihydro-9-hydroxy-9-(ethoxycarbonylmethyl)-10-oxophenanthrene, 9,10-dihydro-9-hydroxy-9-(n-butoxycarbonylmethyl)-10-oxophenanthrene and 9,10-dihydro-9-hydroxy-9-(benzyloxycarbonylmethyl)-10-oxophe-nanthrene. These compounds represent a novel group of phenanthrenes lacking oxygen in the benzene rings. In addition the known limonoid cedrelone, the sterols sitosterol and stigmasterol, the coumarins isopimpinellin and siderin, the furoquinoline alkaloid skimmianine and 2-hydroxy-4-methoxycinnamaldehyde were also isolated and characterized.