Methanol → 2,4-Dibromo-3-methylthiophene

Participants

Reaction Steps

A catholyte of 300 ml of methanol, 100 ml of methylene chloride, 15 g of zinc chloride, 0.5 g of methyltrioctylammonium chloride and 31 g of 3-methyl-2,4,5-tribromothiophene were electrolysed in electrolysis cell 1 at a current density of 50 mA/cm2 at the start and 25 mA/cm2 at the end of the batch, a voltage of 4 or 3 V, a temperature of 34° to 24° C. and pH of -0.8. The current consumption was 14.8 Ah. After addition of 500 ml of water to the catholyte and working up as described in Example 1, 17.4 g of 2,4-dibromo-3-methylthiophene (yield: 73.4%), 0.71 g of 2,3-dibromo-4-methylthiophene (yield: 3%) and 2.92 g of 4-bromo-3-methylthiophene (yield: 17.8%) were obtained.

Provenance & Evidence