NEW OXADIAZOLE DERIVATIVES

摘要

The present invention relates to an oxadiazole derivative of formula (I)1 or a pharmaceutically acceptable salt or N-oxide thereof: wherein, R1 represents a hydrogen atom, a C1-2 alkyl group or a C3-4 cycloalkyl-C1-2 alkyl group, both R2 and R3 represent a C1-2 alkyl group; Ra represents a hydrogen atom or a C1-2 alkyl group; Rb represents a hydrogen atom, a C1-2 alkyl group, a C3-4, cycloalkyl group, a carboxy group, a carbamoyl group or a -CF3 group; Rc represents a linear or branched C2.5 alkyl group substituted with one substituent selected from a hydroxy group, a triazolyl group and a -P(O)(OH)2 group; a -(CH2)(1-2)-C(O)OR' group; a -NR'R" group; a -(CH2)(1-2NR'R" group; a -(CH2)(1-2)-NHC(O)R" group; a -(CH2)(2-4)NH-(CH2)(1-3)-NR'R" group; or a -O-(CH2)(2-3)NR'R" group, wherein: R' represents a hydrogen atom or a C1-2 alkyl group, R" represents a hydrogen atom; a C5-6 cycloalkyl group substituted with a carboxy group; a 5- to 6-membered saturated heterocyclic ring containing one nitrogen atom and substituted with a carboxy(C1-2alkyl) group; or a C1-2 alkyl group optionally substituted by one or more substituents selected from halogen atoms, hydroxy groups, methyl groups, amino groups, carbamoyl groups and carboxy groups; or R' and R" together with the nitrogen atom to which they are attached form (a) a 4 to 6 membered saturated or unsaturated heterocyclic group, which contains, as heteroatom, one N atom and, optionally, one further N atom and which heterocyclic group is substituted with one or more substituents selected from a halogen atom, a hydroxy group, a methyl group, an oxy group and a carboxy group, or (b) a 5 membered heteroaryl group which contains, as heteroatom, one N atom and, optionally, one or more further N atoms and which heteroaryl group is optionally substituted with one substituent selected from an amino group and a carboxy group.