A use of a compound of Formula 1 or its pharmaceutically acceptable salt for the manufacture of a medicament for preventing or treating a dysfunction of gastrointestinal motility: ** Formula ** in which, R1 is a phenyl group substituted with one or more substituents selected from the group consisting of hydroxy, amino, halogen, cyano, nitro, hydroxycarbonyl, C1-5 alkyl (in which C1-5 alkyl is optionally substituted with halogen or amino), C2-6 alkenyl, C2-6 alkynyl , C1-5 alkoxy (wherein C1-5 alkoxy is optionally substituted with halogen), C1-5 alkylthio, mono- or di-C1-5 alkylamino, C1-5 alkylsulfonylamino, C1-5 alkylcarbonylamino, C1-5 alkoxycarbonyl , aminosulfonyl, aminocarbonyl, C1-5 alkylaminocarbonyl and benzyloxycarbonylamino； or a heteroaryl group selected from the group consisting of pyridinyl, pyrimidinyl, pyrazinyl, imidazolyl, pyrazolyl, triazolyl, oxazolyl, thiazolyl, furanyl, pyrrolyl, thiophenyl, naphthyl, indanyl, quinolinyl, quinolinonyl, chromenonyl, dihydroindolonyl, iso -indole-1,3-isoonononyl -dionyl, dihydrobenzimidazolonyl, benzoxazolonyl, benzofuranyl, benzothiophenyl, benzo [d] [1,3] dioxolyl, dihydrobenzo [1,4] dioxinyl, indolyl, indolinyl, benzimidazolyl, benzoxazolyl, benzothiazolyl and which may be in the heterozolyl group； optionally substituted with one or more substituents selected from the group consisting of amino, di-C1-5 alkylamino, cyano, nitro, halogen, C1-5 alkyl (wherein C1-5 alkyl is optionally substituted with halogen), alkoxy C1-5 (wherein C1-5 alkoxy is optionally substituted with halogen), acetyl and C1-5 alkylsulfonyl, R2 is hydrogen； a C1-5 alkyl group optionally substituted with a substituent selected from the group consisting of hydroxy, C1-5 alkoxy, benzylamino (in which the benzylamino is optionally substituted with halogen), phenylamino, C1-5 alkylamino, C3-6 cycloalkylamino , pyrrolidinyl and hydroxy-C1-5 alkylamino； a C1-5 alkoxycarbonyl group； a hydroxycarbonyl group； an aminocarbonyl group； a formyl group； or
