Clostridium difficile toxin inhibitors

A compound of formula (I)

• or a pharmaceutically acceptable salt thereof, wherein:
• Q is CH or N;
• R′ is H, halogen, C1-6alkyl, C1-6alkoxy, CN, NO2, NH2, NHS(O)2C1-6alkyl, NHC(O)C1-6alkyl, NHC(O)C1-6alkylOC1-6alkyl, NHC(O)-isoxazolyl or NHC(O)-pyridyl, wherein isoxazoly and pyridyl are each optionally mono- or di-substituted with C1-3alkyl, and alkyl is optionally substituted with 1-4 halogen;
• W is C(O) or CH2;
• X is CH2, CH(C1-3alkyl), C3-6cycloalkyl, C(O) or S(O)2, and when W is C(O), X cannot be C(O) or S(O)2;
• Y is
• Z is CH2OH, NH2, C(O)OH, R6,
• provided that only when Y is
• Z is R6;
• R is H, C1-6alkyl, C1-6alkyl-OH, C1-6alkyl-N(C1-6alkyl)C1-6alkyl or C0-3alkyl-R7;
• each R1 is independently H, C1-6alkyl, C1-6alkoxy, halogen, NH2, phenyl, pyridyl, pyrazolyl, isoxazolyl, OC1-6alkyl-phenyl, benzodioxolyl or NHC(O)C0-3alkyl-R2, wherein phenyl, pyridyl, pyrazolyl and isoxazolyl are each optionally mono- or di-substituted with substituents independently selected from C1-3alkyl, halogen, C1-3alkoxy, C(O)NHC1-3 alkyl and NHC(O)C1-3 alkyl, and alkyl is optionally substituted with 1-4 halogen;
• R2 is OH, C1-6alkyl, C1-6 alkoxy, N(C1-6 alkyl)C1-6 alkyl, morpholinyl, pyrrolidinyl, piperidinyl, piperizinyl, tetrahydropyranyl, cyclohexyl or pyridyl, wherein morpholinyl, pyrrolidinyl, piperidinyl, piperizinyl, tetrahydropyranyl, cyclohexyl and pyridyl are each optionally mono- or di-substituted with C1-3 alkyl, and alkyl is optionally substituted with 1-4 halogen;
• R3 is H or C1-6alkyl;
• R4 is H, OH, C1-6alkyl, C(O)C1-6alkyl, C(NOH)C1-6alkyl, S(O)2C1-6alkyl, S(O)2-phenyl, or R6, wherein phenyl is optionally mono- or di-substituted with substituents independently selected from halogen, C1-3alkyl and C1-3alkoxy, and alkyl is optionally substituted with 1-4 halogen;
• or R3 and R4 together with the N to which they are attached form:
• each optionally mono-, di-, or tri-substituted with substituents independently selected from halogen and C1-3alkyl, wherein alkyl is optionally substituted with 1-4 halogen;
• R5 is C1-6alkyl-SH, C1-6alkyl-OH, C1-6alkylOC1-6alkyl or R6;
• or R3, R5 together with the N and C(O) to which they are respectively attached form:
• each optionally mono- or di-substituted with C1-3alkyl, wherein alkyl is optionally substituted with 1-4 halogen;
• R6 is
• each optionally mono- or di-substituted with substituents independently selected from C1-3alkyl, C1-3alkoxy, halogen, CN, NH2, S(O)2C1-3alkyl, phenyl, morpholinyl, piperidinyl and piperazinyl, wherein piperidinyl and piperazinyl are each optionally substituted with C1-3alkyl and tert-butyloxycarbonyl, and alkyl is optionally substituted with 1-4 halogen;
• R7 is
• each optionally mono- or di-substituted with substituents independently selected from C1-3alkyl, C1-3alkoxy, halogen, CN, and OH, and alkyl is optionally substituted with 1-4 halogen;
• and
• X is CH or N, and no more one X can be N.