BICYCLIC ENDOTHELIN ANALOGUES

摘要

HA576 BICYCLIC ENDOTHELIN ANALOGUES Endothelin receptor antagonism is exhibited by novel compounds of the formula wherein R1 to R8 are each independently hydrogen or lower alkyl or together with the carbon atom to which they are attached are cycloalkyl (provided that at least one of R1 to R8 is other than hydrogen) and A2 to A21 are as defined in the specification. A novel process of preparation is also described, in which R1 and R2 differ from R7 to R8 and R3 and R4 differ from R5 and R6 in an uncyclized intermediate, which is then oxidized to form the bicyclic compound above in high yield.