Substituted cyclopentanes, tetrahydrofuranes and pyrrolidines as orexin receptor antagonists

A compound of formula

• wherein
• R1 represents an 8- to 10-membered fused bicyclic heteroaromatic group optionally substituted by at least one substituent independently selected from halogen, cyano, hydroxyl, C3-C6 cycloalkyl, C1-C3 alkyl, C1-C3 alkoxy, C1-C3 alkoxycarbonyl, C1-C3 alkoxycarbonylamino, C1-C3 haloalkoxy, —NR4R5, C3-C6 cycloalkylamino, C1-C3 alkylcarbonyloxy, C1-C3 alkylcarbonylamino, sulphonamido, C1-C3 alkylsulphonyl, C1-C3 alkylsulphonylamino and —C(O)NR6R7;
• L represents a bond, CH2, O, NH or N(CH3);
• Ra represents a hydrogen atom or a C1-C3 alkyl or C1-C3 haloalkyl group;
• Rb represents a hydrogen atom or a C1-C3 alkyl or C1-C3 haloalkyl group;
• X represents CF2, CHR8;
• R2 represents a hydrogen atom or a C1-C6 alkyl or C3-C6 cycloalkyl group;
• R3 represents a 5- or 6-membered monocyclic heteroaromatic group optionally substituted by at least one substituent independently selected from halogen, hydroxyl, cyano, C1-C3 alkyl, C1-C3 haloalkyl, C1-C3 hydroxyalkyl, C1-C3 alkoxy, C1-C3 haloalkoxy, C2-C4 alkenyl, C1-C3 alkylcarbonyloxy, C1-C3 alkoxycarbonyl, —NR10R11, —C(O)NR12R13, C3-C6 cycloalkyl, C3-C6 cycloalkyloxy, C3-C6 cycloalkylmethyl or a 5- or 6-membered heteroaryl group, the heteroaryl group being optionally substituted by at least one substituent independently selected from C1-C6 alkyl, C1-C6 alkoxy and C1-C6 haloalkoxy;
• R4 and R5 each independently represent a hydrogen atom or a C1-C3 alkyl or C3-C6 cycloalkyl group, or R4 and R5 may together with the nitrogen atom to which they are attached form a 4- to 7-membered saturated heterocyclic ring optionally substituted by at least one substituent independently selected from halogen, hydroxyl and C1-C3 alkoxy;
• R6 and R7 each independently represent a hydrogen atom or a C1-C3 alkyl or C3-C6 cycloalkyl group, or R6 and R7 may together with the nitrogen atom to which they are attached form a 4- to 7-membered saturated heterocyclic ring optionally substituted by at least one substituent independently selected from halogen and hydroxyl;
• R8 represents a hydrogen or halogen atom or a hydroxyl group;
• R10 and R11 each independently represent a hydrogen atom or a C1-C3 alkyl or C3-C6 cycloalkyl group, or R10 and R11 may together with the nitrogen atom to which they are attached form a 4- to 7-membered saturated heterocyclic ring optionally substituted by at least one substituent independently selected from halogen, hydroxyl and C1-C3 alkoxy;
• and
• R12 and R13 each independently represent a hydrogen atom or a C1-C3 alkyl or C3-C6 cycloalkyl group, or R12 and R13 may together with the nitrogen atom to which they are attached form a 4- to 7-membered saturated heterocyclic ring optionally substituted by at least one substituent independently selected from halogen and hydroxyl;
• or a pharmaceutically acceptable salt thereof.