反应详情

To 400 parts of N,N-dimethylformamide was slowly added 21 parts of phosphorus oxychloride with stirring and ice cooling. Then in small quantities 33.9 parts of 6-chloro-5,7-dimethyl-4-oxo-4H-1-benzopyran-2-carboxamide was added to the solution. After the addition was completed the reaction mixture was stirred at room temperature for 18 hours. The dark solution which resulted was poured into 1500 parts of ice/water. The precipitated solid was filtered off and crystallised from ethanol to give 30.5 parts of 6-chloro-5,7-dimethyl-4-oxo-4H-1-benzopyran-2-carbonitrile, melting point 142°-143° C.

1. additionAfter the addition
2. stirringwas stirred at room temperature for 18 hours
3. customThe dark solution which resulted
4. filtrationThe precipitated solid was filtered off
5. customcrystallised from ethanol