3,4-Dichloroaniline → HCID 22763481, compound

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Reaction Steps

Prepare a solution of 3,4-dichlorophenyl-diazonium chloride by treating 8.2 g. of 3,4-dichloroaniline in 25 ml of concentrated hydrochloric acid with a solution of 3.5 g. of sodium nitrite in 35 ml of water at -5°. Dissolve ethyl 2-(2,4-dichlorobenzyl) acetoacetate (14.3 g.) in 100 ml of ethanol with 8.3 g. of potassium hydroxide in 8.3 ml of water and cool to -5°. Add the solution of the diazonium salt to the latter solution, keeping the temperature at 0°, and stir for 15 minutes. Extract with ether and wash the ether solution with two 75 ml portions of 5% sodium hydroxide and then with water and dry (MgSo4). Evaporate to yield the intermediate: ethyl 2,4-dichlorophenylpyruvate 3,4-dichlorophenyl hydrazone. The analytical sample is obtained from ethanol; m.p. 160°-161°. Dissolve the hydrazone (125 g.) in 700 ml of 20% ethanolic sulfuric acid and boil under reflux for 2 hours. Cool to room temperature and collect the crystalline product. Wash with 50% aqueous alcohol. Recrystallize from ethanol; m.p. 230°-231°.

Provenance & Evidence