7,8-dihydro-5h-1,6-naphthyridine derivatives as positive allosteric modulators of the muscarinic acetylcholine receptor m4 for treating neurological and psychiatric disorders

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

• A is selected from a 5-membered heteroarene, a 5-membered heterocycle, and a 5-membered alicyclic ring system, wherein the heteroarene and heterocycle contain 1 to 2 heteroatoms independently selected from the group consisting of N, O, and S;
• wherein the 5-membered heteroarene, the 5-membered heterocycle, and the 5-membered alicyclic ring system of A are unsubstituted or substituted with 1, 2, or 3 substituents independently selected from C1-3 alkyl, C1-4 fluoroalkyl, C3-6 cycloalkyl, and halogen;
• R1 is selected from C1-4 fluoroalkyl, C3-6 cycloalkyl, phenyl, 5- or 6-membered heteroaryl, —NRaRb and -LRc;
• L is CH2 or O;
• wherein Ra is a 5- or 6-membered heteroaryl or phenyl;
• wherein Rb is hydrogen;
• or
• wherein Ra and Rb together with the N to which they are attached form a heterocyclyl;
• wherein Rc is 5- or 6-membered heteroaryl or phenyl;
• wherein each phenyl, 5- or 6-membered heteroaryl, cycloalkyl, and heterocyclyl of R1, Ra, or Rc is unsubstituted or substituted with 1, 2, or 3 substituents independently selected from C1-4 alkyl, C1-4 fluoroalkyl, —NRdRe, halogen, and C3-6 cycloalkyl;
• wherein Rd and Re are independently selected from hydrogen and C1-4 alkyl;
• R2 is selected from hydrogen, C1-4 alkyl, halogen, —NRgRh, —ORi and C3-6 cycloalkyl;
• wherein Rg is independently selected from C1-4 alkyl, C1-3 hydroxyalkyl, C3-6 cycloalkyl, phenyl, and 5- or 6-membered heteroaryl;
• wherein Rh is independently selected from hydrogen and C1-4 alkyl;
• or
• wherein Rg and Rh together with the N to which they are attached form a heterocyclyl;
• wherein Ri is C1-4 alkyl;
• wherein each 5- or 6-membered heteroaryl, heterocyclyl, phenyl, and C3-6 cycloalkyl of R2 is unsubstituted or substituted with 1, 2, or 3 substituents independently selected from —NRjRk, C1-4 fluoroalkyl, hydroxyl, C1-4 alkyl, halogen, C3-6 cycloalkyl;
• and
• wherein Ri and Rk are independently selected from hydrogen and C1-4 alkyl.