反应详情

2.52 Parts of 4-oxo-4H-1-benzopyran-3-carboxaldehyde are admixed well with 2.10 parts of hydroxylamine hydrochloride, followed by the addition of 30 volume parts of 95 weight % ethyl alcohol and 0.5 volume part of concentrated hydrochloric acid. The whole mixture is refluxed for 6 hours and cooled. The resulting precipitate is recovered by filtration, treated with activated carbon and recrystallized from ethanol. This procedure yields 4-oxo-4H-1-benzopyran-3-carbonitrile as colorless crystals. Melting point: 177°-178° C.

1. temperatureThe whole mixture is refluxed for 6 hours
2. temperaturecooled
3. filtrationThe resulting precipitate is recovered by filtration
4. additiontreated with activated carbon
5. customrecrystallized from ethanol