Positive allosteric modulators of the muscarinic acetylcholine receptor m4

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

• wherein
• X1 is CR3a or N;
• R1 is C1-4 fluoroalkyl, —C1-4fluoroalkylene-OH, C3-6 cycloalkyl, halogen, 5- to 10-membered heteroaryl, phenyl, —NRaRb, or -LRc, the phenyl and heteroaryl being unsubstituted or substituted with 1-4 substituents independently selected from the group consisting of —NRdRe, C1-4 fluoroalkyl, C1-4 alkyl, halogen, and G1;
• Ra is 5- to 10-membered heteroaryl, phenyl or C3-6 cycloalkyl, wherein Ra is unsubstituted or substituted with 1-4 substituents independently selected from the group consisting of —NRdRe, C1-4 fluoroalkyl, C1-4 alkyl, halogen, and C3-6 cycloalkyl;
• Rb is hydrogen, C1-4 alkyl, or G1;
• or
• Ra and Rb together with the N to which they are attached form a heterocyclyl, the heterocyclyl being unsubstituted or substituted with 1-4 substituents independently selected from the group consisting of —NRdRe, C1-4 fluoroalkyl, C1-4 alkyl, halogen, oxo, and G1;
• G1 is C3-6 cycloalkyl, phenyl, 5- to 6-membered heteroaryl, or a 4- to 6-membered heterocyclyl, the heteroaryl and heterocyclyl containing 1-2 heteroatoms independently selected from the group consisting of O, N, and S;
• L is CH2 or O;
• Rc is 5- to 10-membered heteroaryl, phenyl or C3-6 cycloalkyl, wherein Rc is unsubstituted or substituted with 1-4 substituents independently selected from the group consisting of —NRdRe, C1-4 fluoroalkyl, C1-4 alkyl, halogen, and C3-6 cycloalkyl;
• Rd and Re are independently hydrogen or C1-4 alkyl;
• R2 is hydrogen, cyano, —NRgRh, —ORi, 5- or 6-membered heteroaryl, C1-4 alkyl, C1-4 fluoroalkyl, halogen, or C3-6 cycloalkyl;
• Rg is C1-4 alkyl, C1-4 hydroxyalkyl, C3-6 cycloalkyl, CRmRn, phenyl, or 5- or 6-membered heteroaryl;
• Rh is hydrogen or C1-3 alkyl;
• or
• Rg and Rh together with the N to which they are attached form a heterocyclyl;
• Ri is hydrogen, C1-4 alkyl, C1-4 fluoroalkyl, or phenyl;
• Rm and Rn together with the carbon atom to which they are attached form a 4-, 5-, or 6-membered heterocyclyl;
• wherein each 5- or 6-membered heteroaryl, heterocyclyl, phenyl, and C3-6 cycloalkyl of R2, Rg, or Ri are unsubstituted or substituted with 1, 2, or 3 substituents independently selected from the group consisting of —NRjRk, C1-4 fluoroalkyl, hydroxyl, C1-4 alkyl, halogen, and C3-6 cycloalkyl;
• Rj and Rk are independently hydrogen or C1-4 alkyl;
• n is 0, 1, 2, or 3;
• R3, at each occurrence, is independently C1-4 alkyl, cyano, halogen, C3-6 cycloalkyl, C1-4 fluoroalkyl, or ORL;
• R3a is hydrogen, C1-4 alkyl, cyano, halogen, C3-6 cycloalkyl, C1-4 fluoroalkyl, or ORL;
• RL, at each occurrence, is independently C1-3 alkyl or C1-4 fluoroalkyl;
• and
• R4 is 0, 1, 2 or 3 substituents independently selected from C1-4 alkyl.