反应详情

A suspension of 21,8 g (0.1 mole) of 3,7-dichlorobenzo-1,2,4-triazine 1-oxide, 7.5 g of zinc dust and 5.5 g of ammonium chloride in 400 ml of water was stirred vigorously at room temperature for 24 hours. 50 ml of glacial acetic acid were then added, the mixture was stirred for a further hour and the insoluble constituents were then filtered off. The latter were extracted twice with methylene chloride. The combined methylene chloride solutions were washed with water, dried over sodium sulfate and evaporated in vacuo. The residue was recrystallized from wash benzine. 7.5 g, that is to say 37% of theory, of 3,7-dichloro-benzo-1,2,4-triazine with a melting point of 113°-115° C were obtained. ##STR36## (Preparation according to process variant (a))

1. stirringthe mixture was stirred for a further hour
2. filtrationthe insoluble constituents were then filtered off
3. extractionThe latter were extracted twice with methylene chloride
4. washThe combined methylene chloride solutions were washed with water
5. dry with materialdried over sodium sulfate
6. customevaporated in vacuo
7. customThe residue was recrystallized
8. washfrom wash benzine