Dimethylformamide → 2-(4-Iodophenyl)benzamide

Participants

Reaction Conditions

Reaction Steps

Add 2-(4-iodophenyl)benzoic acid (12.0 grams, 0.037 moles, preparation 55), dichloromethane (60 mL), dimethylformamide (0.5 mL, 0.0065 moles), and thionyl chloride (5.72 grams, 0.0481 moles) to a 250 mL 3-neck round-bottom flask equipped with a magnetic stirrer, internal temperature probe, heating mantle, condenser, and nitrogen inlet. Warm the reaction mixture to 36° C. for 45 minutes. Add thionyl chloride (1.7 grams, 0.0143 moles) and stir at 36° C. for 15 minutes. Add tetrahydrofuran (60 mL) dichloromethane (60 mL) and concentrated ammonium hydroxide (25 mL, 0.37 moles) to a 500 mL 3-neck round-bottom flask equipped with a magnetic stirrer, internal temperature probe, and cooling bath. Add the contents of the 250 mL flask to the 500 mL flask over 5 minutes while limiting the temperature to 30° C. Cool the reaction mixture to 18° C. and filter to collect the precipitate. Retain the filter cake. Transfer the filtrate to a separatory funnel and separate the phases. Concentrate the organic phase under reduced pressure (15-25 mm) to a solid, and suspend the solid in methyl-tert-butyl ether (25 mL). Isolate the solid by filtration and combine with the retained filter cake from above. Suspend the combined solids in methyl-tert-butyl ether (40 mL) at ambient temperature. Filter to isolate the solids. Suspend the solids in 50 mL water, and filter to recover the solids. Rinse the filter cake twice with water (20 mL). Dry the solids at 40° C. under reduced pressure (15-25 mm) to provide the title compound (9.7 grams, 0.030 moles, 81.1% yield). 1H NMR (acetone-d6, 500.0 MHz): δ 7.82 (d, 2H), J=8.8; 7.58 (d, 1H, J=8.2); 7.54 (td, 1H), J=7.7, 1.6; 7.46 (td, 1H, J=7.7, 1.1); 7.42 (d, 1H, J=7.6); 7.30 (d, 2H, J=8.8); 6.91 (s, 1H); 6.62 (s, 1H).

Provenance & Evidence