反应详情

The 1-chloro-4-nitro-9H-xanthen-9-one was prepared as follows: Crude 2-(5'-chloro-2-nitrophenoxy)-benzoic acid (50 g) was added to 200 g of concentrated sulfuric acid. The mixture was held at 75° C. for 4.5 hours, and added to a stirred mixture of 1.5 1 of chloroform and water containing ice as needed to maintain the temperature below 35° C. The chloroform layer was separated, washed with 5% sodium bicarbonate, evaporated to dryness and the residue was crystallized from 200 ml of toluene and 30 ml of cyclohexane to provide the product mp 175°-186° C.

1. additioncontaining ice
2. temperatureto maintain the temperature below 35° C
3. customThe chloroform layer was separated
4. washwashed with 5% sodium bicarbonate
5. customevaporated to dryness
6. customthe residue was crystallized from 200 ml of toluene and 30 ml of cyclohexane