Butyl isocyanate → 2-[[[(n-Butyl)aminocarbonyl]aminosulfonyl]methyl]-3-(N,N-dimethylamino)sulfonylbenzoic acid, methyl ester

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Reaction Steps

A mixture of 8.7 g of the product from Example 14, 2.7 g of n-butyl isocyanate, and 3.2 g anhydrous potassium carbonate in 75 ml methyl ethyl ketone was stirred at reflux temperature for 4.5 hours. The resulting suspension was then poured into 250 ml ice-water and the aqueous layer washed with diethyl ether. Concentrated hydrochloric acid was added to the water layer until a yellow solid formed. The crude product was collected by filtration, washed with n-butyl chloride and dried to give 7.9 g of the title compound as a pale yellow solid, m.p. 118°-134°; IR(nujol): 3400, 1725, 1700 cm-1 ; NMR (CDCl3): δ 0.8-1.6 (7H, m), 2.85 (6H, s, SO2N(CH3)2), 3.0 (2H, q), 3.95 (3H, s, CO2CH3), 5.75 (2H, s, --CH2 --), 6.25 (1H, t, NH), 7.2-8.2 (4 H, m).

Provenance & Evidence