Studies on agents with mixed NO-dependent vasodilating and beta-blocking activities.

PURPOSE: A series of derivatives having a propranolol-like moiety linked to NO-donor furoxan substructures were synthesized. The main objective of this investigation was to obtain agents with mixed NO-dependent vasodilating and beta-blocking activities.
METHODS: Most of the target compounds were synthesized from the appropriate furoxans bearing XCH2CH2NH2 (X = O, S, SO2) chains at the 4 position of the ring, using Al(C2H5)3 in methylene chloride solution and (+/-)2,3-epoxypropyl 1-naphtyl ether. Two of the final products (X = CONH) were obtained by coupling the appropriate furoxancarboxylic acids with N-[2-hydroxy-3-(1-naphthoxy)propyl]-ethylenediamine. beta 1- and beta 2-blocking activities were examined on isolated guinea pig right atria and on guinea pig trachea respectively. Vasodilating properties were assessed on endothelium denuded strips of rat aorta.
RESULTS: Some derivatives behave as well balanced "hybrids" displaying NO-dependent vasodilating and beta-blocking properties in the same concentration range. Some others display either prevalent beta-blocking or vasodilating activity. Generally speaking hybrid formation lowers the affinity for beta-receptors, in particular for beta 2-type, to give an increase in beta 1/beta 2 selectivity.
CONCLUSIONS: The furoxan system is a flexible tool in designing analogues of propranolol whose NO-donating and beta-blocking properties are modulated over a wide range.