Hydrochloric Acid → Methyl 4-(chlorosulfonyl)thiophene-3-carboxylate

Participants

Reaction Steps

44.1 G. (0.18 mol) of the obtained 4-chlorosulfonylthiophene-3-carboxylic acid chloride are dissolved in 450 ml. of absolute chloroform, 9.6 g. (0.3 mol) of absolute methanol are added and the solution is heated to reflux for 9 hours [until termination of the hydrogen chloride evolution]. The mixture is then evaporated to dryness in vacuo, the residue crystallizing out. There is obtained 4-chlorosulfonylthiophene-3-carboxylic acid methyl ester, which can be converted into the 4-hydroxy-2-methyl-N-(2-thiazolyl)-2H-thieno[3,4-e]-1,2-thiazine-3-carboxamide 1,1-dioxide in a manner analogous to that described in the last four paragraphs of Example 5.

Provenance & Evidence