1h-pyrazolo[4,3-b]pyridines as pde1 inhibitors

Abstract

The present invention provides 1H-pyrazolo[4,3-b]pyridin-7-amines of formula (I) as PDE1 inhibitors and their use as a medicament, in particular for the treatment of neurodegenerative disorders and psychiatric disorders,

1 - 19 . (canceled) 
     
     
         20 . A compound of formula (I) 
       
         
           
           
               
               
           
         
       
       or a pharmaceutically acceptable salt thereof, wherein:
 L is NH; 
 R1 is methyl; 
 R2 is 2-butyl; 
 R3 is methyl substituted with a 5-membered heteroaryl which is substituted with methyl; and 
 R4 is pyridinyl which is substituted with C 1 -C 3  alkoxy. 
 
     
     
         21 . The compound of  claim 20 , which is the (R) enantiomer of the compound: 
       
         
           
           
               
               
           
         
       
     
     
         22 . A pharmaceutically acceptable salt of the compound of  claim 21 . 
     
     
         23 . A pharmaceutical composition comprising the compound of  claim 21 , or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable excipient. 
     
     
         24 . The compound of  claim 20 , which is the (S) enantiomer of the compound: 
       
         
           
           
               
               
           
         
       
     
     
         25 . A pharmaceutically acceptable salt of the compound of  claim 24 . 
     
     
         26 . A pharmaceutical composition comprising the compound of  claim 24 , or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable excipient. 
     
     
         27 . The compound of  claim 20 , which is the (R) enantiomer of the compound: 
       
         
           
           
               
               
           
         
       
     
     
         28 . A pharmaceutically acceptable salt of the compound of  claim 27 . 
     
     
         29 . A pharmaceutical composition comprising the compound of  claim 27 , or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable excipient. 
     
     
         30 . The compound of  claim 20 , which is the (S) enantiomer of the compound: 
       
         
           
           
               
               
           
         
       
     
     
         31 . A pharmaceutically acceptable salt of the compound of  claim 30 . 
     
     
         32 . A pharmaceutical composition comprising the compound of  claim 30  or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable excipient. 
     
     
         33 . The compound of  claim 20 , which is the (R) enantiomer of the compound: 
       
         
           
           
               
               
           
         
       
     
     
         34 . A pharmaceutically acceptable salt of the compound of  claim 33 . 
     
     
         35 . A pharmaceutical composition comprising the compound of  claim 33  or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable excipient. 
     
     
         36 . The compound of  claim 20 , which is the (S) enantiomer of the compound: 
       
         
           
           
               
               
           
         
       
     
     
         37 . A pharmaceutically acceptable salt of the compound of  claim 36 . 
     
     
         38 . A pharmaceutical composition comprising the compound of  claim 36  or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable excipient.