Heteroaryl Nitrile Compounds Useful as Inhibitors of Cathepsin-S

A compound of the formula (I):

• wherein the
• ring is chosen from:
• each optionally substituted by C1-3 alkyl;
• R1 is C1-7alkyl, C3-7cycloalkyl, aryl, heterocyclyl or heteroaryl each optionally substituted by one or more Rc;
• R2 is hydrogen or C1-7alkyl;
• or R1 and R2 taken together form a C3-7cycloalkyl or C3-7heterocyclyl ring optionally substituted by one or more halogen or C1-7alkyl;
• R3 is —C(O)C1-7alkyl, —C(O)C3-7cycloalkyl, —C(O)aryl, —C(O)heteroaryl, —C(O)heterocyclyl, —C(O)NRaRb, —C(O)ORa, —CH(Rf)-heteroaryl, —CH(Rf)-aryl, —CH(Rf)-heterocyclyl, aryl, C3-7cycloalkyl or heteroaryl, each ring is optionally substituted by one or more Rd;
• R4 and R5 are each independently hydrogen, C1-7alkyl, aryl, or heteroaryl, or
• R4 and R5 taken together may form a C3-7cycloalkyl or C3-7 heterocyclyl ring each ring being optionally substituted by C1-5alkyl;
• Ra, Rb each independently are hydrogen, C1-7alkyl, aryl or heteroaryl, or may be taken together to form a saturated or unsaturated C3-7cycloalkyl or C3-7 heterocyclyl ring;
• Rc is C1-7alkyl, C1-7alkoxy, C3-7cycloalkyl, aryl, benzyl, halogen or —C(O)—O-benzyl;
• Rd each is independently chosen from C1-7alkyl, C1-7alkoxy, C1-7acyl, —C(O)NRaRb, —NH—C(O)—C1-7alkyl, halogen, —CN, —S(O)m—Re, —NH—S(O)m—Re;
• Re is chosen from C1-7alkyl and amino;
• Rf each is independently chosen from hydrogen or C1-7alkyl;
• m is 0-2;
• wherein one or more hydrogens on any one or more of R1, R2, R3, R2, R4, R5, Ra, Rb Rc, Rd, Re, Rf or
• may be replaced by a halogen or deuterium atom;
• with the proviso that
• when
• is (i), and
• neither R1 nor R2 is hydrogen, and
• R3 is —C(O)C1-7alkyl, —C(O)C3-7cycloalkyl, —C(O)aryl, —C(O)heteroaryl, —C(O)heterocyclyl, —CH(Rf)-heteroaryl, —CH(Rf)-aryl, —CH(Rf)-heterocyclyl, aryl, C3-7cycloalkyl or heteroaryl
• then R4 and R5 must either both be hydrogen or they must form a ring.
• or a pharmaceutically acceptable salt thereof.