Patent ID: 7705145

Claim:
A process for the manufacture of 7-methoxy-6-(3-morpholinopropoxy)-3,4-dihydroquinazolin-4-one of Formula II which comprises: (a) the reduction of 4-methoxy-5-(3-morpholinopropoxy)-2-nitrobenzonitrile of Formula III to give 2-amino-4-methoxy-5-(3-morpholinopropoxy)benzonitrile or Formula IV wherein an aqueous slurry of the compound of Formula III is heated in the presence of a water-soluble inorganic reducing agent and the compound of Formula IV so formed is not isolated as such but is extracted as an organic phase with an organic solvent, which organic phase is added to a polar protic solvent and extracting organic solvent is removed by distillation and the resultant solution comprising the intermediate of Formula IV in said polar protic solvent is subjected to the hydration of step (b); (b) the hydration of the compound of Formula IV to give 2-amino-4-methoxy-5-(3-morpholinopropoxy)benzamide of Formula V wherein the reaction is carried out in the resultant solution from step (a) in the presence of an alkali metal base and in a polar protic solvent to form a reaction mixture comprising the compound of Formula V, and wherein the compound of Formula V so formed is not isolated from the reaction mixture as such but is prepared and used in the cyclisation reaction of step (c) as a solution in said polar protic solvent; and (c) the cyclisation reaction of the compound of Formula V to give the compound of Formula II wherein the reaction mixture from step (b) is acidified with formic acid, the resultant mixture is concentrated by distillation under reduced pressure and an excess of formamide is added to act as a reactant and as a solvent, the resultant solution is maintained at an elevated temperature to form compound of Formula II, whereafter the solution is cooled whereby compound of Formula II comes out of solution as a solid precipitate and optionally is removed from the cooled solution by filtration.