反应详情

N′-(3,4-Dichlorophenyl)hydrazine was liberated from its hydrochloride (10.0 g, 46.8 mmol) by partitioning the solid between diluted Na2CO3 solution (10 ml saturated solution and 40 ml water) and AcOEt. The aqueous layer was extracted two more times with AcOEt, the organic extracts were dried (Na2SO4), the solvent was removed in vacuo, and the residue was taken up in dry toluene (100 ml). To this solution acetic anhydride (4.78 g, 46.8 mmol) was slowly added, and the reaction mixture was stirred at room temperature for 15 min. Light petroleum (50 ml) was added, the mixture was cooled in the refrigerator (−20° C.), and the resulting crystals were collected on a sintered glass funnel and washed with cold petrol ether. Recrystallization from MeOH yielded (V) (8.30 g, 81%) as shiny white crystals, mp 179-182° C. (lit. 168-171° C.). TLC CHCl3/MeOH 9:1.

1. customby partitioning the solid between diluted Na2CO3 solution (10 ml saturated solution and 40 ml water) and AcOEt
2. extractionThe aqueous layer was extracted two more times with AcOEt
3. dry with materialthe organic extracts were dried (Na2SO4)
4. customthe solvent was removed in vacuo
5. temperaturethe mixture was cooled in the refrigerator (−20° C.)
6. customthe resulting crystals were collected on a sintered glass funnel
7. washwashed with cold petrol ether
8. customRecrystallization from MeOH