反应详情

Anhydrous potassium carbonate (16.8 g.) was added gradually to a suspension of the known compound 1,2-dihydro-5-chloro-2,4-dioxo-3,1-(4H)-benzoxazine (11.7 g.) in dry dimethyl sulphoxide (110 ml.) and the mixture stirred at room temperature for 20 minutes Dimethyl sulphate (7 ml.) was added dropwise with vigorous stirring at 30°-35° for 12 minutes and the mixture allowed to settle. The supernatant liquid was decanted into an ice/dilute hydrochloric acid mixture (600 ml.; 0.05 M.HCl). The resulting precipitate was collected, washed with water and dried in vacuo to give 1,2-dihydro-1-methyl-5-chloro-2,4-dioxo-3,1-(4H)-benzoxazine m.p. 199°-201° (dec.).

1. additionwas added dropwise
2. customThe supernatant liquid was decanted into an ice/dilute hydrochloric acid mixture (600 ml.; 0.05 M.HCl)
3. customThe resulting precipitate was collected
4. washwashed with water
5. customdried in vacuo