反应详情

First, 60 g of tin(II)chloride was dissolved in 60 ml of concentrated hydrochloric acid, and the mixture was cooled to −30° C., to which a diazonium solution prepared from 19 g of ethyl 5-amino-2-chlorocinnamate and 6.3 g of sodium nitrite was added dropwise at 0° C. or lower. The reaction mixture was stirred at room temperature for 1 hour, and the precipitated crystals were collected by filtration. These crystals were added to ice-water, neutralized with 2N aqueous sodium hydroxide, and extracted with chloroform. The chloroform layer was dried and concentrated, which afforded 7.0 g of ethyl 2-chloro-5-hydrazinocinnamate.

1. additionwas added dropwise at 0° C.
2. filtrationthe precipitated crystals were collected by filtration
3. additionThese crystals were added to ice-water
4. extractionextracted with chloroform
5. dry with materialThe chloroform layer was dried
6. concentrationconcentrated