Studies on the Synthesis of Cholecystokinin A Receptor Antagonists. II. Synthesis and Cholecystokinin A Receptor Inhibitory Activities of Sulfur-Containing Amide-Carboxylic Acid Derivatives

A number of sulfur-containing amide-carboxylic acid derivatives were synthesized and tested for cholecystokinin A (CCK-A) receptor inhibitory activity in order to study structure-activity relationships. Significant CCK-A receptor inhibitory activities were found in only two series, that is, sulfoxide-carboxylic acid derivatives (9) and sulfone-carboxylic acid derivatives (10). As the most preferred compound, 5-(3,4-dichlorophenylsulfonyl)-4-(N,N-dipentylcarbamoyl)pent anoic acid (10n) was selected.