Sulfuryl chloride → 4-(methoxycarbonyl)-2-methylthiophen-3-aminium chloride

Participants

Reaction Conditions

Reaction Steps

11.5 g of methyl 4-amino-5-methyl-2,5-dihydrothiophene-3-carboxylate (2) (60 mmol, content: 90%) were dissolved in 25 ml of CH2Cl2 and cooled to −10° C. A solution of 8.9 g of sulfuryl chloride (66 mmol) in 10 ml of CH2Cl2 in the temperature range of −10-0° C. was added dropwise to this solution over a period of 2 h. The reaction mixture was subsequently stirred at −10-0° C. for another 1 h and then warmed to room temperature. For workup, the reaction mixture was concentrated under reduced pressure. 14.7 g of methyl 4-amino-5-methylthiophene-3-carboxylate hydrochloride (5) were obtained (89% of theory, content: 62.5%, determined as the free amine).

Provenance & Evidence