NMDA receptor modulators and uses thereof

A compound represented by

• or a pharmaceutically acceptable salt, a stereoisomer, and/or an N-oxide thereof;
• wherein
• R1 is —C(O)—C2-C4alkyl, wherein C2-C4alkyl is substituted at one carbon with NH2 or —NH-carbobenzyloxy and at a different carbon by hydroxyl;
• or
• R1 is
• X is N;
• R5′ is H;
• R8 is —C(O)—C2-C4alkyl, wherein C2-C4alkyl is substituted at one carbon with NH2 or —NH-carbobenzyloxy and at a different carbon by hydroxyl;
• R3 and R3′ are independently selected from the group consisting of H, halogen, hydroxyl, phenyl, —C1-C4alkyl, amido, amine, and —C2-C4alkenyl, wherein C1-C4alkyl, C2-C4alkenyl and phenyl are optionally substituted by one or more substituents selected from Ra;
• R2 is selected from the group consisting of H, R7, —S(O)2—C1-C4alkyl, —C1-C4alkyl, hydroxyl, and phenyl, wherein C1-C4alkyl, and phenyl are optionally substituted by one or more substituents selected from Ra;
• R5 is independently selected from the group consisting of H, halogen, —C1-C4alkyl, —C1-C4alkoxy, —C2-C4alkenyl, cyano, amino, phenyl, and hydroxyl, wherein C1-C4alkyl, C2-C4alkenyl and phenyl are optionally substituted by one or more substituents selected from Ra;
• R7 is selected from the group consisting of —C(O)—C1-C4alkyl and —C(O)—O—C1-C4alkyl, wherein C1-C4alkyl is optionally substituted by 1, 2 or 3 substituents selected from Rb;
• Ra is selected, independently for each occurrence, from the group consisting of carboxy, hydroxyl, halogen, amino, phenyl, —C1-C4alkyl, and —C1-C4alkoxy;
• Rb is selected, independently for each occurrence, from the group consisting of carboxy, hydroxyl, halogen, amino, phenyl, —C1-C4alkyl, —C1-C4alkoxy, and —NH—Rc;
• and
• Rc is selected, independently for each occurrence, from the group consisting of —C(O)—O—C1-C4alkyl and —C(O)—C1-C4alkyl.