Process for Preparation of 4-amino-1-isobutyl-1H-Imidazo[4,5-C]-quinoline (Imiquimod)

Abstract

A process for the preparation of imiquimod comprising oxidation of 1-Isobutyl- 1 H-imidazo quinoline quinoline (II) afforded 1-Isobutyl-1H-imidazo-[4,5-c]-quinoline-5-N-oxide (III) which is isolated in pure form as its hydrochloride salt (IV) followed by conversion to 4-chloro derivative (V) and conversion to corresponding 4-iodo derivative (VI) which is a new intermediate. This new intermediate in convened to imiquimod (VIII) and purified via its novel maleate salt.

1 - 21 . (canceled) 
   
   
       22 . A compound selected from the group consisting of: 4-iodo-1-isobutyl-1H-imidazo[4,5-c]quinoline; and 4-amino-1-isobutyl-1H-imidazo[4,5-c]quinoline maleate. 
   
   
       23 . The compound of  claim 22 , comprising 4-iodo-1-isobutyl-1H-imidazo[4,5-c]quinoline. 
   
   
       24 . The compound of  claim 22 , said compound comprising 4-amino-1-isobutyl-1H-imidazo[4,5-c]quinoline maleate. 
   
   
       25 . A process comprising converting 4-iodo-1-isobutyl-1H-imidazo[4,5-c]quinoline into imiquimod. 
   
   
       26 . The process of  claim 25 , comprising converting said 4-iodo-1-isobutyl-1H-imidazo[4,5-c]quinoline into 4-amino-1-isobutyl-1H-imidazo[4,5-c]quinoline maleate, and then converting said 4-amino-1-isobutyl-1H-imidazo[4,5-c]quinoline maleate into imiquimod.