Thionyl Chloride → 4-acetylamino-5-chloro-2-methoxy-N-[1-(2-thenyl)-4-piperazinyl]-benzamide

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Reaction Steps

4-Acetylamino-5-chloro-2-methoxybenzoic acid (3.67 g, 0.015 mole) was treated with thionyl chloride (30 ml) at 50° for 1/2 hour. The mixture was evaporated in vacuo and the residue azeotroped twice with anhydrous toluene (100 ml), redissolved in hot anhydrous toluene (150 ml) and filtered. Triethylamine (2 ml) was added to the filtrate followed by N-amino-N'-2-thenylpiperazine (2.70 g, 0.0137 mole) and the reaction left for 6 hours at room temperature. The mixture was basified with 10% sodium hydroxide (10 ml) and the toluene layer separated, dried over K2CO3 and evaporated in vacuo to yield 4-acetylamino-5-chloro-2-methoxy-N-[1-(2-thenyl)-4-piperazinyl]-benzamide (3.7 g, 64%) as colourless microcrystals, m.p. 178°-181° C. (ex EtOAc-light petroleum 40°-60°).

Provenance & Evidence