4-Nitrobenzyl chloroformate → 1-[4-(N-4-nitrobenzyloxycarbonylamino)benzoyl]-4-[2-(4-chlorophenyl)ethyl]-piperazine

Participants

Reaction Steps

1 g of 1-[4-aminobenzoyl]-4-[2-(4-chlorophenyl)ethyl]-piperazine and 0.4 g of Hunig base (=N-ethyldiisopropylamine) are dissolved in 15 ml of tetrahydrofuran. A solution of 0.75 g of chloroformic acid 4-nitrobenzyl ester in 5 ml of tetrahydrofuran is added dropwise thereto. The reaction solution is stirred for 3.5 hours at room temperature and for 2 hours at a bath temperature of 55°. The solution is concentrated by evaporation and the residue is taken up in methylene chloride and washed with water. Colourless crystals of 1-[4-(N-4-nitrobenzyloxycarbonylamino)benzoyl]-4-[2-(4-chlorophenyl)ethyl]-piperazine having a melting point of 146°-148° are obtained from alcohol.

Provenance & Evidence