REMEDY FOR RENAL DISEASES

摘要

This invention relates to an agent for the treatment of renal disorders comprising a compound of the formula : <IMG> wherein R1 is lower alkyl optionally substituted with a substituent, etc.; and R2 is hydrogen or lower alkyl; or R1 and R2 are taken together with the attached nitrogen atom to form a heterocyclic group optionally substituted with substituent(s); R3 is hydrogen or lower alkyl; and R4 is lower alkyl; or its salt as an active ingredient.