320734-35-8

Questions And Answer

• Preparation

  STEP A: Preparation of 7-chloro-3-hydrazono-oxindole. A solution of 25.0 g of 7-chloro-isatin in 250 ml of ethanol is refluxed for 24 hours, cooled, and precipitate recovered by filtering and washed once with ethanol and twice with pentane to obtain 7-chloro-3-hydrazono oxindole, m.p. 217-219℃. (decomp.).  STEP B: Preparation of 7-chloro-oxindole. To a solution of sodium ethoxide prepared by heating 5.5 g of sodium in 200 ml. of ethanol at 70°℃. is added 17 g of 7-chloro-3-hydrazono-oxindole over a period of 3.5 hours, and the resulting solution is heated at 70℃. for 24 hours. The solvent is evaporated in vacuo, the residue dissolved in water, acidified with 6 N-hydro chloric acid and the resulting precipitate recovered by filtering, washed three times with water, dried by suc tion and crystallized from methylene chloride/ether to obtain 7-chlorooxindole, 28-220℃.;

Supplier

Related Products