Preparation of Benzamides, Benzenesulfonamides, and Methiodides

Benzoyl chloride is a lachrymator and produces hydrochloric and benzoic acids upon hydrolysis. Wear latex gloves when handling this reagent, measure it out in a hood, and avoid inhaling its vapors. Should this reagent come in contact with your skin, immediately flood the area with water and rinse it with 5% sodium bicarbonate solution. 

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Benzamides. In a small round-bottom flask equipped for magnetic stirring, dissolve 0.3 g of the amine in 3 mL of dry pyridine. Slowly add 0.3 mL of benzoyl chloride to this solution. Affix a drying tube dlrectlyto the flask and heat the reaction mixture to 60-70 °C for 30 min then pour the mixture into 25 mL of water with stirring. If the solid derivative precipitates at this time, isolate it by vacuum filtration, and dissolve it in 10 mL of diethyl ether when it is nearly dry. If no precipitate forms, extract the aqueous mixture twice with 5-mL portions of diethyl ether. Combine the extracts. Wash the ethereal solution sequentially with 5-mL portions of water, 1.5 M HCI, and 0.6 A//sodium bicarbonate solution. Dry the ethereal layer over anhydrous sodium sulfate, filter or decant the dried solution, and remove the diethyl ether by one of the techniques described in Section 2.29. Recrystallize the solid derivative from one of the following solvents cyclohexane-hexane mixtures, cyclohexane-ethyl acetate mixtures, 95% ethanol, or aqueous ethanol. 

Transfer any recovered diethyl ether into the container for nonhalogenated organic liquids. Hush all aqueous and ethanolic solutions down the drain, and pour any other filtrates containing organic solvents into the container for nonhalogenated liquids. Spread the desiccant used in the drying tube on a tray in the hood and discard it in the container for nonhazardous solids after the volatiles are removed. 

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