Nitric Acid → 6-Methyl-5-nitrouracil

Participants

Reaction Steps

50.5 g (0.40 mol) of 6-methyluracil (Merck) are introduced in portions over the course of one hour with stirring at 0 to +5° C. into a solution of 200 ml of 100% nitric acid (fuming) and 50 g of phosphorus pentoxide. When the exothermic reaction is complete, the mixture is stirred at +5° C. for a further 5 hours. The reaction mixture is subsequently poured into 1 kg of ice-water. The resultant precipitate is filtered, washed with water and then dried to constant weight, giving 37 g (54%) of 5-nitro-6-methyluracil, pale-yellow powder, m.p. 281° C. with decomposition.

Provenance & Evidence