Preparation of Highly Potent and Selective Non-Peptide Antagonists of the Arginine Vasopressin V_1A Receptor by Introduction of a 2-Ethyl-1H-1-imidazolyl Group

Abstract

To find a new series of arginine vasopressin (AVP) V_1A receptor antagonists, the influence of the 2-phenyl group of 2-phenyl-4′-[(2,3,4,5-tetrahydro-1H-1-benzazepin-1-yl)carbonyl]benzanilide (7) was investigated. Replacement of the 2-phenyl group by a 2-ethyl-1H-imidazol-1-yl group was effective in yielding a V_1A-selective compound. Moreover, this imidazolyl group was introduced in the same position in YM-35471 (6), and further studies of these compounds were performed. Consequently, we found that the (Z)-4′-({4,4-difluoro-5-[(N-cyclopropylcarbamoyl)methylene]-2,3,4,5-tetrahydro-1H-1-benzazepin-1-yl}carbonyl)-2-(2-ethyl-1H-1-imidazol-1-yl)benzanilide (9f) exhibited highly potent affinity and selectivity, and was the most potent antagonist for the V_1A receptor among our compounds. The synthesis and pharmacological evaluation of these compounds are described in this paper