A compound of Formula (I) ** Formula ** in which R1 represents heteroaryl (C1-2) alkyl, in which the heteroaryl is a monocyclic or bicyclic aromatic ring of 5 to elements containing 1, 2 or 3 heteroatoms independently selected from oxygen, nitrogen and sulfur and in which the heteroaryl is unsubstituted or monosubstituted or substituted with (C1-4) alkyl； or (C1-2) heterocyclylalkyl, in which the heterocyclyl is a monocyclic non-aromatic ring of 5 or 6 elements containing one or two nitrogen atoms that is ringed to a phenyl or pyridinyl ring and wherein the heterocyclyl is not substituted or monosubstituted or disubstituted, in which the substituents are independently selected from the group consisting of (C1-4) alkyl and oxo； R2 represents hydrogen or methyl； R3 represents aryl, wherein the aryl is a phenyl or naphthyl group, groups that are independently unsubstituted or monosubstituted or disubstituted, in which the substituents are independently selected from the group consisting of halogen, (C1-4) alkyl, (C1-4) alkoxy, fluoroalkyl (C1-2), fluoroalkoxy (C1-2) and cyano； aryl (C1-2) alkyl, wherein the aryl is a phenyl or naphthyl group, groups that are independently unsubstituted or monosubstituted with halogen； heteroaryl, in which the heteroaryl is a monocyclic or bicyclic aromatic ring of 5 to 10 elements containing 1, 2 or 3 heteroatoms independently selected from oxygen, nitrogen and sulfur and in which the heteroaryl is unsubstituted or monosubstituted or disubstituted, in which substituents are independently selected from the group consisting of halogen, (C1-4) alkyl, cycloalkyl (C3-6), alkoxy (C1-4), fluoroalkyl (C1-2), fluoroalkoxy (C1-2), dialkyl (C1-2) -amino, hydroxy, cyano, phenyl, pyridinyl and heteroaryl (C1-2) alkyl, wherein the heteroaryl is a monocyclic aromatic ring of 5 or 6 elements containing 1 or 2 heteroatoms independently selected from oxygen, nitrogen and sulfur； aryl (C1-2) alkyl sulfonyl, wherein the aryl is a phenyl or naphthyl group；
