Pyridine derivatives, their production and use

摘要

Pyridine derivatives of the formula <IMAGE> wherein the ring A stands for an optionally further substituted benzene ring; the ring B stands for an optionally substituted pyridine ring; Q stands for hydroxyl group, or OQ1 or Q1 wherein Q1 stands for an optionally substituted aliphatic hydrocarbon group; and n denotes 0 or 1, or their salts, which have potassium.channel opening activity and are useful as therapeutic agents of circulatory diseases such as angina pectoris, hypertension, etc.