2-Amino-N-methylbenzenesulfonamide is obtained by treating 2-nitrobenzenesulfonyl chloride with methylamine and subsequent reduction. Used as a dye component. The amides of 2-aminobenzenesulfonic acid can be treated with aldehydes or orthoformic acid esters to give 1,2,4-benzothiadiazine 1,1-dioxides or their dihydro compounds; these substances have been proposed as diuretics.
Step B / Intermediate C4: Synthesis of 2-amino-N-methylbenzenesulfonamide
To a solution of N-methyl-2-nitrobenzenesulfonamide (26 g, 0.12 mol) in methanol (500 mL) was added 10% palladium carbon catalyst (2 g). The reaction mixture was stirred at room temperature under hydrogen atmosphere for 3 hours. Upon completion of the reaction, the catalyst was removed by filtration and the filtrate was concentrated under reduced pressure to afford the target product 2-amino-N-methylbenzenesulfonamide (22 g, 98% yield). The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3): δ 7.45-7.48 (dd, 1H, J=1.6 Hz, 8.0 Hz), 7.24-7.31 (m, 2H), 6.81-6.83 (dd, 1H, J=0.6 Hz, 8.0 Hz), 6.60-6.65 (m, 1H), 5.89 (s 2H), 2.370-2.374 (d, 3H, J=1.6Hz).
[1] Patent: WO2012/92880, 2012, A1. Location in patent: Page/Page column 64
[2] Angewandte Chemie - International Edition, 2010, vol. 49, # 29, p. 4955 - 4957
[3] Patent: WO2007/45868, 2007, A1. Location in patent: Page/Page column 47
[4] Farmaco, Edizione Scientifica, 1954, vol. 9, p. 661,678, 680
[5] Farmaco, Edizione Scientifica, 1957, vol. 12, p. 495,499, 500
