反应详情

40.0 g of 5-chlorosalicyl-amide and 54.0 g of 5-chlorosalicylic acid are boiled under reflux in 400 ml of xylene after addition of 2.5 ml of pyridine. 38 ml of thionyl chloride are added in the course of 2 h, the mixture is stirred for a further 1 h and the solvent is then distilled off under reduced pressure. The residue is suspended in 200 ml of ethanol, filtered off and washed with ethanol. After drying, 6-chloro-2-(5-chloro-2-hydroxyphenyl)benz[e][1,3]oxazin-4-one is obtained as slightly yellow crystals of m.p. 246-248 C.

1. distillationthe solvent is then distilled off under reduced pressure
2. filtrationfiltered off
3. washwashed with ethanol
4. customAfter drying