N-aroyl piperazine derivatives as orexin receptor antagonists

A compound of formula (I):

• wherein:
• Y represents NR2;
• m represents 1, 2, or 3;
• p represents 0 or 1;
• X is O, S, C═O, SO2, or —CH═CH—;
• Ar1 is an optionally substituted phenyl, naphthyl, quinoxalinyl, quinazolinyl, pyridopyrazinyl, benzoxazolyl, benzothiophenyl, benzimidazolyl, naphthyridinyl, pyridinyl, pyrimidinyl, thiazolyl, or benzofuranyl group;
• Ar2 represents a phenyl group or a 5- or 6-membered heterocyclyl group, wherein the phenyl or heterocyclyl group is substituted by R1 and further optional substituents, and wherein said heterocyclyl group is selected from furanyl, thienyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, oxadiazolyl, thiadiazolyl, pyridinyl, triazolyl, triazinyl, pyridazinyl, pyrimidinyl, isothiazolyl, isoxazolyl, pyrazinyl, and pyrazolyl;
• or
• Ar2 represents an optionally substituted group selected from benzofuranyl, benzimidazolyl, quinolinyl, quinoxalinyl, and naphthyl;
• R1 represents a trifluoromethoxy, methoxy, halo, or an optionally substituted phenyl, pyridinyl, pyrazolyl, oxadiazolyl, or pyrimidinyl group;
• R2 represents hydrogen or (C1-4)alkyl;
• wherein the optional substituents for the optionally substituted groups of Ar1, Ar2 and R1 are selected from the group consisting of halogen, hydroxy, oxo, cyano, nitro, (C1-4) alkyl, (C1-4)alkoxy, halo(C1-4)alkyl, halo(C1-4)alkoxy, aryl(C1-4)alkoxy, (C1-4)alkylthio, hydroxy(C1-4)alkyl, (C1-4)alkoxy(C1-4)alkyl, (C3-6)cycloalkyl(C1-4)alkoxy, (C1-4)alkanoyl, (C1-4)alkoxycarbonyl, (C1-4)alkylsulfonyl, (C1-4)alkylsulfonyloxy, (C1-4)alkylsulfonyl(C1-4)alkyl, arylsulfonyl, arylsulfonyloxy, arylsulfonyl(C1-4)alkyl, (C1-4)alkylsulfonamido, (C1-4)alkylamido, (C1-4)alkylsulfonamido(C1-4)alkyl, (C1-4)alkylamido(C1-4)alkyl, arylsulfonamido, arylcarboxamido, arylsulfonamido(C1-4)alkyl, arylcarboxamido(C1-4)alkyl, aroyl, aroyl(C1-4)alkyl, aryl(C1-4)alkanoyl, (C1-4)acyl, aryl, aryl(C1-4)alkyl, (C1-4)alkylamino(C1-4)alkyl, and
• R3R4N—, R3OCO(CH2)r, R3CON(R4)(CH2)r, R3R4NCO(CH2)r, R3R4NSO2(CH2)r and R3SO2NR4(CH2)r wherein each of R3 and R4 independently represents a hydrogen atom or a (C1-4)alkyl group and r represents zero or an integer from 1 to 4;
• or a pharmaceutically acceptable salt thereof.