Methyl vinyl ketone → N-benzyl-2-nitro-N-(3-oxobutyl)benzenesulfonamide

Participants

Reaction Conditions

Reaction Steps

To a solution of benzylamine (10.92 ml, 100 mmol) in dichloromethane (DCM) (150 ml) was added triethylamine (13.67 ml, 100 mmol) followed by a solution of 2-nitrobenzene-1-sulfonyl chloride (22.16 g, 100 mmol) in DCM (70 ml) at 5-10° C. with stirring. The mixture was stirred for 1 hour (complete by HPLC), stirring continued for 1 hour, washed with water, brine, most of DCM removed on a rotavap, Ethyl acetate (150 ml) was added, another 25-30 ml distilled off under reduced pressure. To the resulting solution potassium tert-butoxide (0.561 g, 5.00 mmol) was added followed by methyl vinyl ketone (9.07 ml, 110 mmol) with stirring in one portion at 20-25° C. The mixture was stirred for 1 hour at 20-25° C., diluted with heptane (70 ml), washed with brine+1N HCl (5 ml), organic phase was dried (MgSO4), evaporated to approx 100 ml, seeded with crystals of compound F (crystallisation started), cooled to 0-5° C., diluted slowly with heptane to approx 200 ml. The mixture was aged in ice for 1 hour, crystals collected, washed with heptane, dried on air to give N-benzyl-2-nitro-N-(3-oxobutyl)benzenesulfonamide (31.4 g, 87 mmol, 87% yield).

Provenance & Evidence