Methyl chloroformate → 4H-Pyrido(1,2-a)pyrimidine-3-acetamide, 6-methyl-4-oxo-N-propyl-

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Reaction Steps

A mixture containing 2.18 g (0.01 mol) of 6-methyl-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-acetic acid and 1.55 ml (0.011 mol) of triethylamine in 60 ml of chloroform is cooled below -10° C. by ice-salt. A solution of 0.945 g (0.01 mol) of methyl chloroformate in 5 ml of chloroform is dropped to the above mixture at -12° C. during 7 minutes. After stirring for 5 minutes, 0.65 g (0.011 mol) of propylamine dissolved in 10 ml of chloroform is dropped to the above solution at -15° C. during 10 minutes. The reaction mixture is stirred at -15° C. for 1 hour, then allowed to stand overnight under cooling by ice. For working up, the reaction mixture is washed 3 times with 40 ml of 5% sodium hydrogen carbonate solution each, then 3 times with 40 ml of water each. The organic phase is dried over anhydrous sodium sulfate, filtered and evaporated. After thoroughly triturating the residue with cold ethyl acetate, 0.8 g (30.9%) of the named compound is obtained, m.p.: 96°-98° C. after recrystallization from ethyl acetate.

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