反应详情

To a solution containing 51.0 g of 3-cyano-4-(4-methoxyethoxy-5-sulfophenylazo)-1-phenyl-5-pyrazolone prepared as described in Step (1) above, 250 ml of acetone and 50 ml of phosphorous oxychloride, 50 ml of N,N-dimethylacetamide was added dropwise at a temperature below 50° C. After completion of the addition, the mixture was stirred for 1 hour and was poured gradually into 1.0 liter of ice water. The crystals thus precipitated were collected by filtration, washed with 100 ml of acetonitrile and air-dried. Yield: 46.7 g. Melting Point: 181° to 183° C.

1. customprepared
2. additionwas added dropwise at a temperature below 50° C
3. additionAfter completion of the addition
4. customThe crystals thus precipitated
5. filtrationwere collected by filtration
6. washwashed with 100 ml of acetonitrile
7. customair-dried