反应详情

After mixing 270 g (0.762) of 5-phenyl-(4-ethoxycarbonyl-2-nitrophenyl)-4-isoxazolin-3-one prepared in the above step, 800 ml of 1,2-dichloroethane, 125 g of zinc chloride, 103 g of paraformaldehyde, and 20 ml of sulfuric acid, the reaction was performed for 1.5 hours in a steam bath while blowing hydrogen chloride gas in the reaction system. During the reaction, crystals deposited. After cooling, water was added to the reaction mixture and crystals formed were recovered by filtration, washed with water, and dried to provide 270 g of the desired product with a yield of 88%. The melting point thereof was 190° C. to 191° C.

1. customDuring the reaction, crystals
2. temperatureAfter cooling
3. customformed
4. filtrationwere recovered by filtration
5. washwashed with water
6. customdried