Reaktion #56283

Reaktionsgleichung

3-chlorosulfonylthiophene-2-carboxylic acid methyl ester

chloroform

methylamine

→

3-methylsulfamoylthiophene-2-carboxylic acid methyl ester

Lösungsmittel

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeis led through the solution at 10° C. until a moistened pH paper
2. 2
   Sonstigean alkaline reaction with the solution
3. 3
   Sonstigeto react at room temperature for a further 2 hours
4. 4
   Extraktionof a 5% sodium bicarbonate solution [the aqueous phases are back-extracted in each case once with chloroform]
5. 5
   TrocknenThe combined organic phases are dried over sodium sulfate
6. 6
   Sonstigeevaporated
7. 7
   SonstigeThe crystalline residue is digested with ether for purification

Vorschrift

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.

Quelle