Spiro-lactam nmda receptor modulators and uses thereof

A method of treating neuropathic pain, the method comprising:

• administering to a patient in need thereof a compound represented by formula (I):
• or a stereoisomer, or an N-oxide, and/or a pharmaceutically acceptable salt thereof, wherein:
• Rb is selected from the group consisting of H, halogen, hydroxyl, cyano and C1-C6alkyl;
• R is H, C1-C6 alkyl, or —C(O)—C1-C6alkyl;
• R1 is H or C1-C6 alkyl;
• R2 is H or C1-C6 alkyl;
• R3 is C1-C6 alkyl;
• C1-C6 alkoxy;
• —O—C1-C6 alkylene-phenyl;
• C2-C6 alkenyl;
• C2-C6 alkynyl;
• C3-C6 cycloalkyl;
• phenyl;
• or heteroaryl, wherein heteroaryl includes from 5 to 6 ring atoms and 1, 2, or 3 of the ring atoms are independently selected from the group consisting of N, O, and S;
• wherein R3 is optionally substituted with one, two, or three substituents independently selected from the group consisting of —NH2, halogen, C1-C6 alkyl, C1-C6 alkoxy, hydroxyl, phenyl (optionally substituted with one, two, or three substituents independently selected from Ra), benzyl (optionally substituted with one, two, or three substituents independently selected from Ra), and —C1-C6 alkylene-C3-C6 cycloalkyl (optionally substituted with one, two or three substituents independent selected from halogen and C1-C6 alkyl);
• Ra is selected from the group consisting of halogen, C1-C6 alkyl (optionally substituted with one, two or three halogens), C3-C6 cycloalkyl (optionally substituted with one, two or three halogens), and C1-C6 alkoxy (optionally substituted with one, two or three halogens);
• R4 is H or C1-C6 alkyl;
• R5 is H or C1-C6 alkyl;
• X is selected from the group consisting of H;
• C1-C6 alkyl;
• hydroxyl;
• C1-C6 alkoxy;
• —CO2H;
• —C(O)NRcRd;
• and heteroaryl, wherein heteroaryl includes from 5 to 6 ring atoms;
• 1, 2 or 3 of the ring atoms are independently selected from the group consisting of N, O, and S;
• and heteroaryl may be optionally substituted with one, two, or three substituents independently selected from the group consisting of halogen, C1-C6 alkyl, C1-C6 alkoxy, hydroxyl, and phenyl;
• and
• Rc and Rd are each independently selected from the group consisting of H, C1-C6 alkyl and phenyl;
• or Rc and Rd together, with the nitrogen to which they are attached, form heterocyclyl, wherein heterocyclyl includes from 4 to 6 ring atoms but not more than two ring heteroatoms (including the nitrogen atom attached to Rc and Rd), and the second ring heteroatom, when present, is independently selected from the group consisting of N, O, and S;
• and heterocyclyl is optionally substituted with one, two or three substituents independently selected from the group consisting of halogen, cyano, oxo, and C1-C6 alkyl.