A mixture of 3-(2-chloroethyl)-9-hydroxy-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one hydrochloride (formula-5) (11.1 grams), 6-fluoro-3-(4-piperidinyl)-1,2-benzoisoxazole mono hydrochloride (formula-6) (10 grams), sodium carbonate (7.5 grams), potassium iodide (0.64 grams) in acetonitrile (100 ml) was heated to 80-85° C. The reaction mixture was refluxed for 17 hrs under nitrogen. Then it was cooled to −10° C. and stirred for 30 min. The solid obtained was filtered and washed with chilled acetonitrile. The solid was taken in water and treated with sodiumhydrosulphite (hydrose) (2.0 grams). The solid was filtered and washed with water and dried at 50° C. to provide the title compound.
