An Extremely Quick Procedure for 2,3,5-Trbbromothiophene

Abstract

2,3,5-Tribromothiophene, the intermediate for the preparation of 3-bromo-thiophene¹ has been prepared by adding three mole equivalents of bromine to a mixture of thiophene and chloroform². After the bromination which takes about two days, the reaction mixture is treated for 7 hours with ethanolic potassium hydroxide. This procedure, especially when it is carried out on a large scale involves a great risk of an uncontrolled, vigorous reaction of chloroform with the base. Seemingly, the checkers of the Organic Synthesis procedure, who needed the tribromothiophene as starting material for 3-bromothiophene, have not experienced the complications mentioned.