A compound represented by the general formula (I-a): (I-a) [wherein Rand R each means hydrogen, lower cycloalkyl, lower alkyl, etc.；R means hydrogen, lower cycloalkyl, lower alkyl, etc.； Rand R each means lower alkyl, lower cycloalkyl, etc. or Rand R are bonded to each other to form lower cycloalkylidene； andR means lower alkyl, lower haloalkyl, etc.]. This compound functionsas an LCE inhibitor and is useful as a therapeutic agent for various circulatorydiseases, nervous diseases, metabolic diseases, reproductive diseases, digestivetract diseases, neoplasm, infectious diseases, etc.
