| abstract |
A dipeptidyl peptidase IV inhibitor which is satisfactory in activity, stability, and safety and has excellent medicinal activity. It is a compound represented by the following general formula or a pharmaceutically acceptable salt thereof. (I) [R<1> and R<2> each represents hydrogen, optionally substituted C1-6 alkyl, or -COOR<5> or R<1> and R<2> form a 3- to 6-membered cycloalkyl in cooperation with the carbon atom bonded thereto; R<5> represents hydrogen or optionally substituted C1-6 alkyl; R<3> represents hydrogen or optionally substituted C6-10 aryl; R<4> represents hydrogen or cyano; D represents -CONR<6>-, -CO-, or -NR<6>CO-; R<6> represents hydrogen or optionally substituted C1-6 alkyl; E represents -(CH2)m- (m is an integer of 1 to 3), -CH2OCH2-, or -SCH2-; n is an integer of 0 to 3; and A represents an optionally substituted bicyclic heterocyclic group or bicyclic hydrocarbon group. |