Chloroform → methyl 3-(N-methylsulfamoyl)thiophene-2-carboxylate

Reaktionsgleichung

[CH3:1][O:2][C:3]([C:5]1[S:6][CH:7]=[CH:8][C:9]=1[S:10](Cl)(=[O:12])=[O:11])=[O:4].C(Cl)(Cl)Cl.[CH3:18][NH2:19]>O>[CH3:1][O:2][C:3]([C:5]1[S:6][CH:7]=[CH:8][C:9]=1[S:10](=[O:12])(=[O:11])[NH:19][CH3:18])=[O:4]

Komponenten

Versuchsvorschrift

43.5 G. (0.18 mol) of the obtained 3-chlorosulfonylthiophene-2-carboxylic acid methyl ester are dissolved in 450 ml. of absolute chloroform and dry methylamine is led through the solution at 10° C. until a moistened pH paper shows an alkaline reaction with the solution. The mixture is then allowed to react at room temperature for a further 2 hours, the solution always remaining alkaline. The solution is then shaken out with 500 ml. of water and 500 ml. of a 5% sodium bicarbonate solution [the aqueous phases are back-extracted in each case once with chloroform]. The combined organic phases are dried over sodium sulfate and then evaporated. The crystalline residue is digested with ether for purification. There is obtained 3-methylsulfamoylthiophene-2-carboxylic acid methyl ester of melting point 115°-122° C.