3-Thenyl bromide could be produced through the following synthetic route.

A 5-l. three-necked flask is fitted with a stirrer, an efficient reflux condenser, and a wide-mouthed funnel with a 15-cm. water-cooled stem. A solution of 220 g. (2.24 moles) of 3-methylthiophene and 4 g. of benzoyl peroxide in 700 ml. of dry benzene is brought to vigorous reflux in this flask, and a mixture of 356 g. (2 moles) of N- and 4 g. of benzoyl peroxide is added portionwise through the wide-mouthed funnel. The dry powder is added as rapidly as the violent foaming will permit and is worked down through the stem of the funnel with a stirring rod. Refluxing benzene washes the lower part of the funnel continuously. The total addition requires about 20 minutes. As soon as the foaming from the last addition of N-bromosuccinimide has subsided, the flask is cooled, first with a water bath and then an ice bath. The succinimide is filtered off and washed once with dry benzene.

The filtrate is immediately transferred to a distilling flask, and the benzene is removed at reduced pressure. The residue is distilled at 1 mm., and the fraction boiling between 75° and 78° is collected. The major portion boils at 76° and has nD25 1.6030. This procedure yields 250–280 g. (71–79%) of a water-white product, which remains colorless for several days when stored over calcium carbonate in a refrigerator.

Notice: This preparation should be run in a well-ventilated hood.