Studies on Antiulcer Drugs. III. Synthesis and Antiulcer Activities of Imidazo[1, 2-a]pyridinylethyl-benzoxazoles and Related Compounds. A Novel Class of Histamine H2-Receptor Antagonists

A series of imidazo[1, 2-a]pyridinylalkylbenzoxazole derivatives was synthesized and tested for histamine H2-receptor antagonist, gastric antisecretory and antiulcer activities. Some of 2-amino-6-[2-(imidazo[1, 2-a]pyridin-2-yl)ethyl]benzoxazole derivatives were found to have good pharmacological activities. Among them, 2-amino-6-[2-(7-methoxy-3-methylimidazo[1, 2-a]pyridin-2-yl)ethyl]benzoxazole (II-11) and 2-acetamido-6-[2-(7-methylimidazo[1, 2-a]pyridin-2-yl)ethyl]benzoxazole (II-38) showed potent antisecretory and cytoprotective activity. The structure-activity relationships of these compounds are discussed.