Methanol → 2,2-dimethyl-3,4-dihydro-2H-1,3-benzoxazin-4-one

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Reaction Steps

To a solution of salicylamide (20.0 g, 0.146 mol; Aldrich Chemical Company, Inc., Milwaukee, Wis.) in 2,2-dimethoxypropane (300 mL) was added pyridinium p-toluenesulfonate (11.0 g, 0.044 mol) and then heated to reflux for 2 h. TLC (dichloromethane: methanol=20:1) indicated the reaction was complete. The solvent was removed and then the residue was taken up in ethyl acetate (150 mL). The solution was washed twice with sodium bicarbonate and once with brine. The organic layer was dried and concentrated under reduced pressure to afford (I-30a) (26.0 g, yield: 93.4%) as a yellow solid, which was used to next step without any purification.

Provenance & Evidence