CARBOXYLIC ACID DERIVATIVE AND SALT THEREOF

The present invention provides a novel carboxylic acid compound, a salt thereof or a hydrate of them useful as an insulin sensitizer, and a medicament comprising the compound as an active ingredient. That is, the present invention provides a carboxylic acid compound represented by the following formula, a salt thereof, an ester thereof or a hydrate of them. Wherein R represents a hydrogen atom, hydroxyl group, halogen, carboxyl group, or a C1-6 alkyl group etc., each of which may have one or more substituents; L represents a single bond, or a C1-6 alkylene group, a C2-6 alkenylene group or a C2-6 alkynylene group, each of which may have one or more substituents; M represents a single bond, or a C1-6 alkylene group, a C2-6 alkenylene group or a C2-6 alkynylene group, each of which may have one or more substituents; T represents a single bond, or a C1-3 alkylene group, a C2-3 alkenylene group or a C2-3 alkynylene group, each of which may have one or more substituents; W represents a carboxyl group; - - - represents a single bond etc. ; X represents a single bond, oxygen atom, a group represented by -NRCQ O- (wherein Q represents an oxygen atom or sulfur atom; and R represents a hydrogen atom, formyl group, or a C1-6 alkyl group etc., each of which may have one or more substituents), -OCQ NR- (wherein Q and R are as defined above), -CQ NRO- (wherein Q and R are as def ined above), ONRCQ - (wherein Q and R are as defined above), - Q SO2- (wherein Q is an oxygen atom or -NR- (wherein R represents a hydrogen atom, formyl group, or a C1-6 alkyl group etc., each of which may have one or more substituents)) or -SO2Q - (wherein Q is as defined above), (wherein, provided that R and R, and/or R and R may together form a ring, Q and Q are the same as or different from each other and each represents an oxygen atom, (O)S(O) or NR (wherein NR is as defined above)); Y represents a 5- to 14-membered aromatic group etc., which may have one or more substituents and one or more hetero atoms; and the ring Z represents a 5-to 14-membered aromatic group which may have 0 to 4 substituents and one or more hetero atoms, and wherein part of the ring may be saturated.