Dimethyl Sulfoxide → 4-Carbobenzoxy-1-(o-nitrophenyl)piperazine-2-carboxylic acid

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Reaction Steps

A mixture of 12.0 g. (0.04 mole) of 4-carbobenzoxypiperazine-2-carboxylic acid, 8.4 g. (0.06 mole) of o-nitrofluorobenzene, 16 g. of triethylamine and 100 ml. of dimethylsulfoxide is heated at 90° for 81/2 hours, cooled, diluted with water (300 ml.) and extracted with ether. The aqueous phase is then acidified with dilute hydrochloric acid and extracted with ether. The combined ether extracts are diluted with 1/3 its volume of pentane. The ether-pentane solution is washed with water, dried (MgSO4) and concentrated to give 14 g. of yellow-orange glassy product. Thin layer chromatography analysis (10% acetic acid in benzene on a silica gel plate) shows 1 main spot with a faint second impurity spot.

Provenance & Evidence