3764-01-0

67-52-7

3764-01-0

Example 2: 128.1 g (1 mol) of barbituric acid and 500 ml (5.5 mol) of phosphorus trichloride were sequentially added to a reaction flask, heated to reflux and maintained for 4 hours. Subsequently, 270 ml (3.1 mol) of phosphorus trichloride and 213 g (3 mol) of chlorine were slowly added dropwise to the reaction system, and the reaction solution was kept as a light yellow suspension during the treatment. The amount of chlorine gas should be strictly controlled during the titration process to avoid overdose, and the specific operation was referred to Example 1. After the titration was completed, the reaction was continued to reflux for 1 hour. After completion of the reaction, phosphorus trichloride is removed by distillation. Finally, 2,4,6-trichloropyrimidine was obtained by distillation under pump vacuum according to the method described in Example 1. The yield of the product was 148 g, the yield was 81% of the theoretical value (in terms of barbituric acid), and the absence of 2,4,5,6-tetrachloropyrimidine in the product was confirmed by GC assay.