反应详情

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.

1. temperaturewas heated
2. temperatureThe suspension was then cooled to 20°
3. customthe solid product was collected
4. dissolutionThis was subsequently dissolved in 30 ml of water
5. customformed
6. temperatureThe mixture was warmed briefly
7. customto produce a filterable suspension which
8. temperaturewas then cooled
9. filtrationfiltered
10. washrinsed with water