2-substituted 5,6-diaryl-pyrazine derivatives as cb1 modulator

A compound of formula (I):

• wherein R1 and R2 independently represent phenyl, thienyl or pyridyl, each of which is independently optionally substituted by one or more groups represented by Z;
• Z represents a C1-8alkyl group, a C1-6alkoxy group, hydroxy, halo, trifluoromethyl, trifluoromethylthio, trifluoromethoxy, trifluoromethylsulphonyl, nitro, mono or di C1-3alkylamido, C1-3alkylsulphonyl, C1-3alkylsulphonyloxy, C1-3alkoxycarbonyl, carboxy, cyano, carbamoyl, mono or di C1-3alkyl carbamoyl, sulphamoyl, acetyl, an aromatic heterocyclic group, optionally substituted by halo, alkyl, trifluoromethyl or trifluoromethoxy or Z represents a saturated or partially unsaturated 5- to 8-membered heterocyclic group containing one or more heteroatoms selected from nitrogen, oxygen or sulphur wherein the heterocyclic group is optionally substituted by one or more C1-3alkyl, hydroxy, fluoro, benzyl or an amino group —NRxRy in which Rx and Ry independently represent H or C1-4alkyl;
• R3 represents a group of formula (CH2)nCOOR7 in which n is 0, 1, 2, 3 or 4, and R7 represents a C4-12alkyl group, a C3-12cycloalkyl group or a (C3-12cycloalkyl)C1-3alkyl-group each of which is optionally substituted by one or more of the following:
• a C1-6alkyl, fluoro, amino or hydroxyl group, or R7 represents a group —CH2)aphenyl in which a is 0, 1, 2, 3 or 4, and the phenyl group is optionally substituted by one or more groups represented by Z which may be the same or different or R7 represents a saturated or partially unsaturated 5- to 8 membered heterocyclic group containing one or more of the following:
• oxygen, sulphur or nitrogen;
• wherein the heterocyclic group is optionally substituted by one or more C1-3alkyl, C1-3acyl, hydroxy, amino or benzyl groups;
• or
• R3 represents a group of formula —(CH2)p—O—(CH2)p—R8 in which o represents an integer 1, 2, 3 or 4, and p represents an integer 0, 1, 2, 3 or 4, and R8 represents a C1-12alkyl group optionally substituted by one or more of the following:
• a C1-6alkyl, fluoro, hydroxy, or an amino group —NRxRy in which Rx and Ry independently represent H or C1-4alkyl;
• or R8 represents phenyl optionally independently substituted by one or more Z groups or R8 represents an aromatic heterocyclic group or a saturated or partially unsaturated 5- to 8 membered heterocyclic group containing one or more of the following:
• oxygen, sulphur or nitrogen wherein each of these rings is optionally substituted by one or more groups represented by Z which may be the same or different;
• or
• R3 represents a group of formula —(CH2)qR9 in which q is 2, 3 or 4 and R9 represents a C3-12cycloalkyl group, phenyl, an aromatic heterocyclic group or a saturated or partially unsaturated 5- to 8 membered heterocyclic group containing one or more of the following:
• oxygen, sulphur or nitrogen wherein each of these rings is optionally substituted by one or more groups represented by Z which may be the same or different;
• or
• R3 represents a group of formula —(CH2)m—O—(CO)—R10 in which m represents an integer 0, 1, 2, 3 or 4, and in which R10 represents a C1-12alkyl group optionally substituted by one or more fluoro, hydroxy, or amino groups or R10 represents a group of formula —(CH2)qR9;
• or
• R3 has the following formula:
• wherein R1 i represents hydroxy, fluoro, carboxy, a C1-6alkoxycarbonyl group or an amino group —NRxRy in which Rx and Ry independently represent H or C1-4alkyl;
• d is 1, 2 or 3;
• R12 represents H or a C1-3alkyl group;
• and
• R3 represents a group of formula CONH—Rz, in which Rz is a piperidinyl ring substituted by a C1-6alkanoyl group or R3 represents a group —COG in which G is a dihydroindole or a dihydroisoindole, linked through nitrogen to the carbonyl,
• or a pharmaceutically acceptable salt thereof.