Hydrochloric Acid → 2-(5-Aminopyrid-2-ylamino)-1,1-bis(phenylsulphonyl)ethene

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Reaction Steps

A mixture of 1,1-bis(phenylsulphonyl)-2-(5-nitropyrid-2-ylamino)ethene (2.23 g), concentrated hydrochloric acid (2 ml), palladium on charcoal catalyst (5% w/w; 1.5 g) and dimethylformamide (50 ml) was hydrogenated at 25° C. and atmospheric pressure until three molar equivalents of hydrogen had been taken up. After filtration to remove the catalyst, the dimethylformamide was removed under vacuum below 40° C. and the residue was treated with methanol (25 ml) and stirred for 30 minutes, and then allowed to stand for 24 hours. The resulting solid was then filtered off, dissolved in chloroform (25 ml), treated with anhydrous potassium carbonate (5 g), and stirred from 2 hours. The mixture was filtered, and the chloroform was removed in vacuo. The resulting residue was recrystallised from a mixture of acetonitrile and diethyl ether and dried thoroughly at 100° C./0.1 mmHg, to give 2-(5-aminopyrid-2-ylamino)-1,1-bis(phenylsulphonyl)ethene (0.5 g), m.p. 172°-174° C.

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