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With triethylamine; In acetone; at 20℃; |
d) 3,4-Diaminophenyl 2,6-difluorobenzenesulfonate may be prepared in the following manner:To a solution of 2 g of 3,4-diaminophenol in 150 cm3 of acetone are added 2.264 cm3 of triethylamine and 3.425 g of <strong>[60230-36-6]2,6-difluorobenzenesulfonyl chloride</strong>. The reaction medium is stirred at a temperature in the region of 20° C. overnight. The insoluble material is filtered off and rinsed with three times 50 cm3 of acetone, and the filtrate is evaporated to dryness under reduced pressure (3.5 kPa). The residue is taken up in 300 cm3 of dichloromethane, washed with three times 50 cm3 of water, dried over magnesium sulfate, filtered and evaporated to dryness under reduced pressure. After flash chromatography on a column of silica [eluent: dichloromethane/methanol (95/5 by volume)], 650 mg of 3,4-diaminophenyl 2,6-difluorobenzenesulfonate are obtained in the form of a black resin, the characteristics of which are as follows:1H NMR spectrum at 300 MHz: 4.57 (broad s, 2H); 4.77 (broad s, 2H); 6.02 (dd, J=3.0 and 8.5 Hz, 1H); 6.33 (d, J=3.0 Hz, 1H); 6.37 (d, J=8.5 Hz, 1H); 7.38 (t, J=9.0 Hz, 2H); 7.87 (m, 1H)Mass spectrum MS (ES+): m/z=301 [MH+]3,4-Diaminophenol may be prepared as described by A. Schmidt et al. in Organic and Biomolecular Chemistry, 2003, 1 (23), 4342. |