4765-77-9

1193-21-1

4765-77-9

The general procedure for the synthesis of 6-chloropyrimidin-4(3H)-ones from 4,6-dichloropyrimidines is as follows: Intermediate 1: Synthesis of 6-chloro-3H-pyrimidin-4-one 4,6-Dichloropyrimidine (Aldrich; 10.00 g, 67.1 mmol), concentrated hydrochloric acid (50 mL), water (50 mL), and dioxane (50 mL) were mixed and heated at 70 °C for 6 h, and subsequently cooled to room temperature to obtain a pink solution. The solvent was removed by evaporation under reduced pressure (using a vacuum pump) to obtain a pink solid. Ethanol (50 mL) was added to the solid and the mixture was heated until the solid was completely dissolved. The solution was cooled slowly in a warm water bath at about 50°C. After standing overnight, it was filtered to obtain an off-white solid, 6-chloro-3H-pyrimidin-4-one (5.02 g, 57% yield), with a melting point of 193-194°C (literature value: 192-193°C, see DJ Brown and JS Harper, J. Chem. Soc. 1961, 1298-1303). 1H NMR (d6-DMSO) data: δ 6.50 (s, 1H), 8.19 (s, 1H), 13.00 (br s, 1H).