Investigations on the chemistry of berbanes. 10. Synthesis of raunescinone analogues with hypotensive and antihypertensive activity.

The pharmacologically active (methylenedioxy)- and diethoxyepialloberbane keto esters I have been synthesized with use of the readily available keto esters 2 as starting material. By choice of the appropriate reaction sequence both antipodes of keto ester 2a can be employed to provide any enantiomer of the desired raunescinone analogue 1a. Hypotensive, antihypertensive, and central depressant effects of 1a are described. The principle effect observed for 1a was a potent hypotensive and antihypertensive effect of long duration without depression of the central nervous system.