Substituted tricyclic compounds as indoleamine 2,3-dioxygenase inhibitors

A compound of formula (I), or a pharmaceutically acceptable salt thereof:

• wherein:
• n is 0 or 1;
• A is selected from (1) —CH═ and (2) —N═;
• V is selected from (1) absent and (2) —C(O)—;
• W is selected from (1) —C(O)—NH— and (2) —NH—C(O)—;
• R1 is selected from (1) aryl and (2) heteroaryl, wherein each of the aryl and heteroaryl is optionally substituted with 1-3 substituents independently selected from:
• (a) halogen, and
• (b) C1-6 alkyl, optionally substituted with 1-4 halogens;
• each occurrence of R2 is independently selected from:
• (1) hydrogen and (2) C1-6 alkyl;
• or alternatively, the two R2 groups together with the carbon to which they are attached form a C3-4 cycloalkyl, wherein the C3-4 cycloalkyl is optionally substituted with C1-6 alkyl;
• R3 is hydrogen, n is 1, and R4 and R5 together with the carbons to which they are attached form a C3-4 cycloalkyl;
• or alternatively, R5 is hydrogen, n is 1, and R3 and R4 together with the carbons to which they are attached form a C3-4 cycloalkyl;
• or alternatively, R5 is absent, n is 0, and R3 and R4 together with the carbons to which they are attached form a C3-4 cycloalkyl;
• or alternatively, R4 is selected from (1) hydrogen and (2) C1-6 alkyl optionally substituted with 1-3 halogens, n is 1, and R3 and R5 together with the carbons to which they are attached and the carbon to which R4 is attached form a C4-5 cycloalkyl;
• R is selected from:
• (1) hydrogen,
• (2) aryl,
• (3) C1-6 alkyl, optionally substituted with 1-4 substituents halogens,
• (4) C3-6 cycloalkyl,
• (5) —O—C1-6 alkyl, optionally substituted with phenyl,
• (6) —O—C3-6 cycloalkyl,
• (7) —O-heterocyclyl, and
• (8) heteroaryl,
• wherein each of the aryl of (2) and heteroaryl of (8) is optionally substituted with 1-3 substituents independently selected from:
• (a) halogen,
• (b) —OH,
• (c) C1-6 alkyl, optionally substituted with 1-4 substituents independently selected from (i) —OH and (ii) halogen,
• (d) —O—C1-6 alkyl, optionally substituted with 1-4 substituents independently selected from (i) —OH and (ii) halogen,
• (e) C3-6 cycloalkyl,
• (f) —O—C3-6 cycloalkyl, and
• (g) —C(O)—O—C1-6 alkyl.