Diethyl 2-Propynylmalonate → 2-Amino-5-(prop-2-yn-1-yl)pyrimidine-4,6-diol

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Reaction Steps

A mixture of 5.0 g ethyl 2-carboethoxy-4-pentynoate [J. Org. Chem. 40, 851 (1975)] and 2.5 g of guanidine carbonate was heated to reflux in 50 ml of absolute ethanol for 24 hours. The suspension was then cooled to 20° and the solid product was collected. This was subsequently dissolved in 30 ml of water and acidified to pH 3 with 1N hydrochloric acid whereupon a thick precipitate formed. The mixture was warmed briefly to produce a filterable suspension which was then cooled, filtered and rinsed with water, then acetone. The yield of 2-amino-6-hydroxy-5-(2-propynyl)-4(3H)-pyrimidinone was 1.3 g (32%) as a slightly pink powder, m.p. 292°-293° dec. An NMR spectrum (60 MHz) in trifluoroacetic acid solution exhibited absorptions at 2.2 (1H), and 3.6 (2H) indicating the title compound.

Provenance & Evidence