A compound represented by formula (I): ** (See formula) ** wherein R1 is (1) a C1-6 alkyl group optionally substituted with 1 to 5 substituents selected from (a) a halogen atom, (b ) a C3-8 cycloalkyl group optionally substituted with 1 to 3 C1-6 alkyl groups, (c) a C1-6 alkoxycarbonyl group, and (d) a carbamoyl group, (2) an optionally C3-10 cycloalkyl group substituted with 1 to 3 C1-6 alkyl groups, or (3) a C6-14 aryl group optionally substituted with 1 to 3 substituents selected from (a) a halogen atom, (b) a C1-6 alkyl group optionally substituted with 1 to 3 halogen atoms, and (c) a cyano group； R2 is a hydrogen atom or a cyano group； R3 is a C1-3 alkyl group optionally substituted with 1 to 3 substituents selected from a halogen atom and a C1-6 alkoxy group； R4 is (1) a C1-6 alkyl group optionally substituted with 1 to 3 substituents selected from (a) a halogen atom, (b) a cyano group, (c) a hydroxy group, (d) an optionally mono amino group or disubstituted with C1-6 alkyl-carbonyl group (s), and (e) a carbamoyl group optionally mono or disubstituted with C1-6 alkyl group (s), and (2) a C3-10 cycloalkyl group, (3) a C6-14 aryl group optionally substituted with 1 to 3 substituents selected from a carbamoyl group optionally mono or disubstituted with C1-6 alkyl group (s), (4) a 5 or 6 membered non-aromatic heterocyclic group having an atom of oxygen, or ...Un compuesto representado por la fórmula (I): **(Ver fórmula)** en donde R1 es (1) un grupo alquilo C1-6 opcionalmente sustituido con 1 a 5 sustituyentes seleccionados de (a) un átomo de halógeno, (b) un grupo cicloalquilo C3-8 opcionalmente sustituido con 1 a 3 grupos alquilo C1-6, (c) un grupo alcoxi-C1-6-carbonilo, y (d) un grupo carbamoilo, (2) un grupo cicloalquilo C3-10 opcionalmente sustituido con 1 a 3 grupos alquilo C1-6, o (3) un grupo arilo C6-14 opcionalmente sustituido con 1 a 3 sustituyentes seleccionados de (a) un átomo de halógeno, (b) un grupo alquilo C1-6 opcionalmente sustituido con 1 a 3 á
