Large conductance calcium-activated K channel opener

摘要

There are disclosed a large conductance calcium-activated K channel opener comprising a compound of the formula (I):; wherein ring A is a 5-membered heterocyclic ring containing any one of O, N or S, which ring may be substituted by R⁴, R¹ is aryl, heterocyclic or heterocycle-substituted carbonyl; R² is hydrogen, halogen, carboxy, amino, alkyl, alkoxycarbonyl, alkenyl or cycloalkyl; R³ is aryl, heterocyclic or alkyl; and R⁴ is hydrogen or alkyl, each of substituents may be substituted,or a pharmaceutically acceptable salt thereof as an active ingredient.