反应详情

A mixture of 23.4 parts of 6-chloro-5,7-dimethyl-4-oxo-4H-1-benzopyran-2-carbonitrile, 7.8 parts of sodium azide, 6.4 parts of ammonium chloride and 200 parts of N,N-dimethylformamide was stirred and heated on the steam bath for 18 hours. Most of the solvent was then removed by distillation under reduced pressure. A solution of the residue in 400 parts of water was acidified with 20% hydrochloric acid. The precipitated solid was filtered off, washed with water and crystallised from dioxan to give 15.5 parts of 5-(6-chloro-5,7-dimethyl-4-oxo-4H-1-benzopyran-2-yl) tetrazole as a colourless solid, melting point 246°-247°C (decomposition).

1. temperatureheated on the steam bath for 18 hours
2. customMost of the solvent was then removed by distillation under reduced pressure
3. filtrationThe precipitated solid was filtered off
4. washwashed with water
5. customcrystallised from dioxan