Question

organic synthesis volume 4 JOHN WALLEY AND SONS

Answer 1

A. N,N-Diethyl-2-methoxybenzamide (2). An oven-dried, two-necked, 500-mL flask equipped with a septum cap, nitrogen bubbler, and magnetic stirrer is charged with 2-methoxybenzoic acid (20 g, 0.13 mol) (Note 1) under nitrogen. Thionyl chloride (135 mL, 220 g, 1.85 mol) (Note 2) is added with stirring, resulting in slow effervescence. Dimethylformamide (DMF, 0.34 mL, 320 mg, 4.4 mmol) (Note 3),(Note 4) is added dropwise via syringe after which effervescence becomes much more vigorous (CAUTION: Sulfur dioxide and hydrogen chloride are evolved). The solution is stirred for 0.5 hr, at which time no further effervescence is visible. Half of the thionyl chloride is removed under reduced pressure on a rotary evaporator, toluene (100 mL) is added, and the mixture is evaporated to dryness.