A compound represented by the following general formula (I) or a pharmacologically acceptable salt thereof, wherein A represents a C3 to C12 cycloalkyl group which may be substituted by one to three selected from a fluoro group, a hydroxy group, a C1 to C6 alkyl group, etc； R 1 , R 2 , and R 3 each independently represent a hydrogen atom, a fluoro group, or a C1 to C6 alkyl group； R 4 represents a hydrogen atom or a prodrug group； and Y represents -CH 2 -CHR 5 -CH 2 -NHR 6 (wherein R 5 represents a hydrogen atom, a C1 to C6 alkyl group, or a C1 to C6 alkoxy group, and R 6 represents a hydrogen atom or a prodrug group), or the like exhibits excellent TAFIa inhibitory activity and is useful as a therapeutic drug for myocardial infarction, angina pectoris, acute coronary syndrome, cerebral infarction, deep vein thrombosis, pulmonary embolism, and the like.
