US Patent 7166590 Amino acid derivatives

A compound of the formula (I):[wherein R1 is (substituted) alkyl, alkoxy, phenyl, hetero ring etc.; A is bond, CO, SO2; R2 is H, (substituted) alkyl etc.; D is alkylene etc.; E is COO, OCO, O, S, SO, SO2 etc.; R3 is (substituted) alkyl, carbocyclic ring, hetero ring; J is O, NR16 (R16 is H, substituted alkyl); R4 is (substituted) alkyl, carbocyclic ring, hetero ring.] or non-toxic salt thereof, and an N-type calcium channel blocker comprising it as an active ingredient.