Epoxysuccinic acid derivatives

摘要

A compound of the general formula: wherein R<1> represents a carboxyl group which may optionally be esterified or amidated; R<2> represents a cyclic group which may optionally be substituted or a polar group; n is an integer of 0 to 6; R<3> represents hydrogen or a hydrocarbon residue which may optionally be substituted; R<4> represents (1) a hydrocarbon residue which is substituted by an optionally protected amino group or (2) an alkenyl group; or R<3> and R<4> may be combined with the adjacent nitrogen atom to form a heterocyclic group containing at least two hetero atoms, or a salt thereof. The compound or a salt thereof of the present invention inhibits thiol proteases such as cathepsin L and B and serves well as a prophylactic/therapeutic agent for bone diseases such as osteoporosis.