Benzanilide → N-Phenylbenzimidoyl chloride

참여 물질

반응 단계

5MeO-TPT was prepared by a modified version of the routes described by D. Enders et al. in Synthesis 2003, page 1292, and by K. Potts et al. in J. Org. Chem. 32, page 224. A mixture of 98.6 g (0.5 mol) benzanilide and 75 mL (1.0 mol) thionyl chloride was heated on steam for 20 hours after initial vigorous outgassing. The resulting mixture was then stripped at about 26.67 kPa (20 mmHg) and 60° C. for 3 hours, leaving 108.4 g of N-phenylbenzimidoyl chloride as a low-melting green solid. The solid was dissolved in 250 mL ethyl acetate and stirred at 5° C. while adding a mixture of 54.05 g (0.5 mol) phenylhydrazine and 51.0 g (0.5 mol) triethylamine dropwise, with the temperature of the solution slowly rising to 20° C. The resulting mixture was washed with 1000 mL of 2 weight percent acetic acid. Solid product was present and another 400 mL of ethyl acetate was added to the washed mixture, with some solid still observed. The ethyl acetate portion of the mixture was separated and filtered, yielding 25.1 g of desired product, and the resulting mother liquor was stripped, 150 mL isopropanol and 50 mL water were added, and the resulting solid was filtered and dried to provide 35.9 g initially and 4.4 g as the final crop, for a total yield of 65.4 g (0.227 mol, 46 percent) of N-phenylbenzamide phenylhydrazone as a brown solid.

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