Methanol → 3,4-Dibromo-2-methylthiophene

Participants

Reaction Steps

A catholyte of 400 ml of methanol, 200 ml of methylene chloride, 1 g of tin(II) chloride, 5 g of tetramethylammonium chloride and 20.4 g of 2-methyl-3,4,5-tribromothiophene were electrolysed in the electrolysis cell 1 at a current density of 25 mA/cm2, a voltage of 3.8 to 2.9 V and a temperature of 30° C. The current consumption was 8.4 Ah. After addition of 500 ml of water to the catholyte, phase separation and removal of the methylene chloride by distillation, 12.98 g of 3,4-dibromo-2-methylthiophene (yield: 83.1%), 0.45 g of a mixture of 2,3-dibromo-5-methylthiophene and 2,4-dibromo-5-methylthiophene (yield: 2.7%) and 0.071 g of unreacted 2-methyl-3,4,5-tribromothiophene were obtained.

Provenance & Evidence