Acetic Anhydride → 6-Amino-1-ethyl-1,2,3,4-tetrahydropyrimidine-2,4-dione

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Reaction Steps

To a solution of 127.5 g (1.5 mol) cyanoacetic acid and 200 ml of acetic anhydride was added 120 g (1.36 mol) of ethylurea. The solution was stirred at 60°-70° C. for 2 hours. After cooling, white crystals were filtered off and washed with ethanol. Yield 153 g (74%) (I). This was stirred in 1 liter of hot water and 160 ml of 2 N NaOH was added in portions so the solution the whole time was basic. The reaction mixture was refluxed for 20 minutes and then neutralized with 5 N HCl. After cooling, white crystals were filtered off. Yield 100 g (65%) (II) NMR.

Provenance & Evidence