Estos compuestos son moduladores de receptores metabotropicos de glutamato (mGluR), particularmente, el receptor mGluR2. Por tanto, son utiles como agentes farmacéuticos, especialmente en el tratamiento y/o prevencion de una diversidad de trastornos del sistema nervioso central (SNC), que incluyendo, pero sin limitacion, afecciones neurodegenerativas agudas y cronicas, psicosis, trastornos de déficit cognitivo, convulsiones, ansiedad, depresion, migrana, dolor, trastornos del sueno y emesis. Reivindicacion 1: Un compuesto de la formula (1): en donde: R1 está seleccionado del grupo consistente en hidrogeno, metilo, fluorometilo, etilo, 2-fluoroetilo, propilo, hidroxietilo, 2-(tetrahidro-piran-2-iloxi)-etilo; R2 está seleccionado del grupo consistente en hidrogeno, metilo, fluorometilo, etilo, 2-fluoroetilo, propilo, metoximetilo, etoximetilo, 2-fluoroetoximetilo, etoxi-1-fluoroetilo, isopropoximetilo, -COOH, fenilo, bencilo, 2-, 3-, 4-, o 5-fluorofenilo, 2-, 3-, 4-, o 5-fluorobencilo, 2,4-difluorofenilo, 2,4-difluoro-bencilo, fenoxi, benciloxi, 2-, 3-, 4-, o 5-fluorofenoxi, 2-, 3-, 4-, o 5-fluorobenciloxi, 2,4-difluorofenoxi, 2,4-difluorobenciloxi, hidroximetilo, hidroxietilo, morfolinilmetilo, pirrolidinilmetilo, piperidinilmetilo, tetrahidrofuranilmetoximetilo, fenilo, ciclopropilo, ciclopropilmetilo y ciclopentiloximetilo; y R3, R4 y R5 son iguales o diferentes y, de manera independiente entre sí, están seleccionados del grupo consistente en hidrogeno, halogeno, CF3, alquilo(C1-6), alcoxi(C1-6), ciclohexilo, 1-metilciclohexilo, 4-metoxi-ciclohexilo, 4,4'-difluorociclohexilo, ciclohexenilo, 4-fluoro-ciclohexenilo, biciclo[3.3.1]nonilo, biciclo[3.3.1]noniletilo, 1,1',1'',3,3',3ö-hexafluoro-2-hidroxi-propilo; o bien dos de R3, R4 y R5 están en carbonos adyacentes y tomados junto con los carbonos a los cuales están unidos forman un anillo de cinco o seis miembros; o una de sus sales, o uno de sus solvatos o uno de sus hidratos.These compounds are modulators of metabotropic glutamate receptors (mGluR), particularly the mGluR2 receptor. Therefore, they are useful as pharmaceutical agents, especially in the treatment and / or prevention of a variety of central nervous system (CNS) disorders, which including, but not limited to, acute and chronic neurodegenerative conditions, psychosis, cognitive deficit disorders, seizures, anxiety, depression, migraine, pain, sleep disorders and emesis. Claim 1: A compound of the formula (1): wherein: R1 is selected from the group consisting of hydrogen, methyl, fluoromethyl, ethyl, 2-fluoroethyl, propyl, hydroxyethyl, 2- (tetrahydro-pyran-2-yloxy) - ethyl; R2 is selected from the group consisting of hydrogen, methyl, fluoromethyl, ethyl, 2-fluoroethyl, propyl, methoxymethyl, ethoxymethyl, 2-fluoroethoxymethyl, ethoxy-1-fluoroethyl, isopropoxymethyl, -COOH, phenyl, benzyl, 2-, 3-, 4-, or 5-fluorophenyl, 2-, 3-, 4-, or 5-fluorobenzyl, 2,4-difluorophenyl, 2,4-difluoro-benzyl, phenoxy, benzyloxy, 2-, 3-, 4-, or 5-fluorophenoxy, 2-, 3-, 4-, or 5-fluorobenzyloxy, 2,4-difluorophenoxy, 2,4-difluorobenzyloxy, hydroxymethyl, hydroxyethyl, morpholinylmethyl, pyrrolidinylmethyl, piperidinylmethyl, tetrahydrofuranylmethoxymethyl, phenyl, cyclopropyl, cyclopropyl, cyclopropylmethyl and R3, R4 and R5 are the same or different and, independently of each other, are selected from the group consisting of hydrogen, halogen, CF3, (C1-6) alkyl, (C1-6) alkoxy, cyclohexyl, 1-methylcyclohexyl, 4-methoxy-cyclohexyl, 4,4'-difluorocyclohexyl, cyclohexenyl, 4-fluoro-cyclohexenyl, bicyclo [3.3.1] nonyl, bicyclo [3.3.1] nonylethyl, 1,1 ', 1' ', 3,3' , 3ö-hexafluoro-2-hydroxypropyl; or two of R3, R4 and R5 are in adjacent carbons and taken together with the carbons to which they are attached form a ring of five or six members; or one of its salts, or one of its solvates or one of its hydrates.