4-Methoxybenzenesulfonyl chloride → N-(tetrahydro-2H-pyran-2-ylmethoxy)-4-methoxy-1-benzenesulfonamide

Participants

Reaction Steps

2-(tetrahydro-2H-pyran-2-ylmethoxy)-1H-isoindole-1,3(2H)-dione (6.8 mmol, 1.77 g) was combined with hydrazine (6.8 mmol, 0.21 mL) in anhydrous THF (15 mL) under nitrogen. The reaction immediately formed a white suspension and was allowed to stir at room temperature for 2 hours. The suspension was filtered directly into a flask containing 4-methoxybenzenesulfonyl chloride (6.8 mmol, 1.40 g) and diisopropylethylamine (8.1 mmol, 1.42 mL) was added. After stirring at room temperature for 24 hours, the reaction was concentrated to a yellow solid. The resulting solid was partitioned between ethyl acetate and 1N HCl, and the organic layer was separated and washed with a saturated aqueous solution of sodium bicarbonate and brine, and dried over magnesium sulfate. The crude product was concentrated to a yellow solid and purified by silica gel chromatography (2:1 hexanes/ethyl acetate). The purified product was combined with ether and filtered to remove the residual phthalimide-hydrazine biproduct. The final product was crystallized using hexanes and ethyl acetate to provide 141 mg (7%) of white crystals. Rf=0.3 (2:1 hexanes/ethyl acetate); H1-NMR (CDCl3): δ 7.83 (2H,d), 7.05 (1H,s), 6.97 (2H,d), 4.01-3.86 (3H,m), 3.86 (3H,s), 3.63-3.57 (1H,m), 3.42-3.36 (1H,m), 1.88-1.78 (1H,m), 1.59-1.43 (4H,m), 1.3-1.15 (1H,m).

Provenance & Evidence