Optically active pyrrolopyridazine derivatives

摘要

An optically active pyrrolopyridazine compound of the formula (I) or a pharmaceutically acceptable salt thereof:wherein R<1 >is alkyl; R<2 >and R<3 >are each independently alkyl; R<4 >is optionally substituted aryl; and A is imino, oxygen or sulfur. The pyrrolopyridazine compound or pharmaceutically acceptable salts thereof of the present invention exhibit excellent gastric acid secretory inhibition activity and gastric mucous membrane protection activity, as well as excellent antibacterial activity against Helicobacter pylori. They are useful medicines and are particularly useful for treating or preventing ulcerative diseases.