Tetrazole compounds as orexin receptor antagonists

A compound of formula (I)

• wherein
• X represents —CH2—, —CH2—CH2—, —CH2—CH2—CH2—, or a bond;
• Y represents —CH2— which is optionally mono-substituted with (C1-4)alkyl;
• Z represents —CH2—, or —S—;
• R1 represents aryl or heteroaryl, wherein said aryl or heteroaryl independently is unsubstituted, or mono-, di-, or tri-substituted, wherein the substituents are independently selected from the group consisting of (C1-4)alkyl;
• (C1-4)alkoxy;
• fluoroalkyl;
• fluoroalkoxy;
• halogen;
• N(CH3)2;
• phenyl and phenyloxy, wherein said phenyl or phenyloxy independently is unsubstituted or mono-, or di-substituted wherein the substituents are independently selected from the group consisting of (C1-4)alkyl, (C1-4)alkoxy, fluoroalkyl, fluoroalkoxy, and halogen;
• or,
• in case X represents —CH2—, R1 additionally represents (C1-6)alkyl, or (C3-6)cycloalkyl;
• R2 represents phenyl which is unsubstituted;
• or mono-, di-, or tri-substituted, wherein the substituents are independently selected from the group consisting of (C1-4)alkyl, (C1-4)alkoxy, halogen, fluoroalkyl, and fluoroalkoxy;
• or
• R2 represents a naphthyl group or a biphenyl group which groups independently are unsubstituted, or mono-, or di-substituted, wherein the substituents are independently selected from the group consisting of (C1-4)alkyl, (C1-4)alkoxy, fluoroalkyl, fluoroalkoxy, and halogen;
• and
• R3 represents hydrogen or methyl;
• or a salt thereof;
• with the exception of the following compounds:
• N-(2-Benzyl-2H-pyrazol-3-yl)-2-[1-(2,5-dimethyl-phenyl)-1H-tetrazol-5-ylsulfanyl]-acetamide;
• 2-[1-(2,5-Dimethyl-phenyl)-1H-tetrazol-5-ylsulfanyl]-N-(2-thiophen-2-ylmethyl-2H-pyrazol-3-yl)-acetamide;
• N-[2-(3-Chloro-benzyl)-2H-pyrazol-3-yl]-2-(1-phenyl-1H-tetrazol-5-ylsulfanyl)-acetamide;
• N-[2-(2,5-Dimethyl-phenyl)-5-methyl-2H-pyrazol-3-yl]-2-(1-phenyl-1H-tetrazol-5-ylsulfanyl)-acetamide;
• N-(5-Methyl-2-phenyl-2H-pyrazol-3-yl)-2-(1-m-tolyl-1H-tetrazol-5-ylsulfanyl)-acetamide;
• N-[2-(4-Fluoro-phenyl)-5-methyl-2H-pyrazol-3-yl]-2-(1-phenyl-1H-tetrazol-5-ylsulfanyl)-acetamide;
• 2-[1-(2,5-Dimethyl-phenyl)-1H-tetrazol-5-ylsulfanyl]-N-(5-methyl-2-phenyl-2H-pyrazol-3-yl)-acetamide;
• 2-[1-(3,5-Dimethyl-phenyl)-1H-tetrazol-5-ylsulfanyl]-N-(5-methyl-2-p-tolyl-2H-pyrazol-3-yl)-acetamide;
• 2-[1-(2,4-Dimethyl-phenyl)-1H-tetrazol-5-ylsulfanyl]-N-(2,5-dimethyl-2H-pyrazol-3-yl)-acetamide;
• N-(5-Methyl-2-p-tolyl-2H-pyrazol-3-yl)-2-[1-(4-trifluoromethoxy-phenyl)-1H-tetrazol-5-ylsulfanyl]-acetamide;
• 2-[1-(2,5-Dimethyl-phenyl)-1H-tetrazol-5-ylsulfanyl]-N-(5-methyl-2-o-tolyl-2H-pyrazol-3-yl)-acetamide;
• 2-[1-(2,6-Dimethyl-phenyl)-1H-tetrazol-5-ylsulfanyl]-N-(5-methyl-2-phenyl-2H-pyrazol-3-yl)-acetamide;
• 2-[1-(3-Fluoro-phenyl)-1H-tetrazol-5-ylsulfanyl]-N-(5-methyl-2-phenyl-2H-pyrazol-3-yl)-acetamide;
• 2-[1-(3,4-Dimethyl-phenyl)-1H-tetrazol-5-ylsulfanyl]-N-(5-methyl-2-phenyl-2H-pyrazol-3-yl)-acetamide;
• N-(5-Methyl-2-phenyl-2H-pyrazol-3-yl)-2-(1-o-tolyl-1H-tetrazol-5-ylsulfanyl)-acetamide;
• N-(5-Methyl-2-phenyl-2H-pyrazol-3-yl)-2-(1-p-tolyl-1H-tetrazol-5-ylsulfanyl)-acetamide;
• 2-[1-(2,3-Dimethyl-phenyl)-1H-tetrazol-5-ylsulfanyl]-N-(5-methyl-2-phenyl-2H-pyrazol-3-yl)-acetamide;
• 2-[1-(2,4-Dimethyl-phenyl)-1H-tetrazol-5-ylsulfanyl]-N-(5-methyl-2-phenyl-2H-pyrazol-3-yl)-acetamide;
• and
• N-(5-Methyl-2-phenyl-2H-pyrazol-3-yl)-2-(1-phenyl-1H-tetrazol-5-ylsulfanyl)-acetamide.