Acetone → Benzamide

Participants

Reaction Conditions

Reaction Steps

81.3 g of 2-methoxy-4-acetamino-5-methylsulphinylbenzoic acid (0.30 mole), 600 ml of acetone, 120 ml of water and 41.7 ml of triethylamine with a density of 0.726 (0.30 mole) are placed in a 1 liter flask fitted with an agitator, a thermometer, a condenser and a dropping funnel. The mixture is cooled to 0° C. and 40.8 g of isobutyl chloroformate (0.30 mole) is poured in drop by drop. It is agitated for 30 minutes with the cooling bath removed, cooled to 0° C. again and 54.6 g of 1-cyclohexyl-2-aminomethyl-pyrrolidine (0.30 mole) is poured in drop by drop. The mixture is reacted for 1 hour at room temperature with agitation, and left to stand. The solution is evaporated to dryness. A paste is obtained and is dissolved in 200 ml of soda and 400 ml of water. It is heated to reflux for 2 hours, and 50 ml of a mixture distilling over at low temperature is distilled off then put back under reflux. The reaction medium is left to stand, then the suspension is extracted four times with 200 ml of methylene chloride. The organic phase is washed twice with 300 ml of 10% hydrochloric acid, the aqueous phase is filtered with carbon black and the filtrate is made alkaline with 300 ml of 40% soda. The suspension is extracted 3 times, each time with 300 ml of methylene chloride. The organic solution is washed with water and dried over magnesium sulphate. The solution is filtered and evaporated to dryness. 42.5 g (36%) of benzamide is obtained; this does not crystallise.

Provenance & Evidence