A compound represented by the following general formula (I) or a pharmacologically acceptable salt thereof, wherein R1 represents a C1 to C6 alkyl group which may be substituted by one to three groups selected from substituent group A, or the like (substituent group A: a hydroxy group, a halogeno group, a cyano group, a nitro group, an amino group, a carboxy group, a C1 to C3 alkyl group, etc.); R2, R3, and R8 each independently represent a hydrogen atom or a C1 to C3 alkyl group; R4, R5, R6, R7, R9, and R10 each independently represent a hydrogen atom or the like; and R11 represents a hydrogen atom or the like, has TAFIa enzyme inhibitory activity and is useful as a therapeutic drug for myocardial infarction, angina pectoris, acute coronary syndrome, cerebral infarction, deep vein thrombosis, pulmonary embolism, or the like.