Inhibitors of indoleamine 2,3-dioxygenase and methods of their use

A compound of formula (I):

• wherein:
• R1 is a straight or branched C1-C8 alkyl substituted with
• R2,
• Y is CH or N;
• L1 is independently a bond or a straight or branched C1-C8 alkylene;
• L2 is independently a bond, a straight or branched C1-C8 alkylene,
• —OC(O)N(Rc)CH(Rb)—, —C(O)N(Rc)L3-, C3-C6 cycloalkyl,
• R2 is independently NH2,
• L3 is independently a straight or branched C1-C6 alkylene;
• L4 is independently a bond, a straight or branched C1-C6 alkylene wherein two carbon atoms of said alkylene are optionally replaced by —C(O)N(Rc)— or —N(Rc)C(O)—;
• R3, R4, R5 and R6 are independently H or C1-C4 alkyl;
• R7 and R8 are independently H or C1-C6 alkyl;
• R9 is aryl optionally substituted with one to three substituents selected from:
• halo, OH, CN, C1-C6 alkyl, —OC1-C6 alkyl, C1-C6 haloalkyl, benzyl, and phenoxy;
• Ra is independently halo, OH, CN, C1-C6 alkyl, —OC1-C6 alkyl, or C1-C6 haloalkyl;
• Rb and Rc are independently H, or C1-C6 alkyl;
• Rd is independently H, C1-C6 alkyl, —CH2OC(O)(C1-C6 alkyl), —CH2OC(O)O(C1-C6 alkyl), or Bn;
• and
• Re is independently C1-C6 alkyl optionally substituted with a substituent selected from halo, OH, CN, C1-C4 alkyl, —OC1-C6 alkyl, and C1-C4 haloalkyl;
• or a salt, a stereoisomer, a tautomer, or a solvate thereof.