Bromic acid, reaction with hydrobromic

A. J. Balard showed that bromic acid is decomposed by hydrobromic acid into bromine and water by hydrochloric acid into water and bromine chloride and by hydriodic acid into water and iodine bromide. There are nine reactions belonging to this set, namely, chloric, bromic, and iodic acids each with each of the three haloid acids—HCl, HBr, and HI. The kinetics of these reactions have been studied extensively.2 W. Bray has shown that the velocity of the reaction between... 

The reactions can be performed more simply with hydrochloric acid and hydro-bromic acid. The reaction between terpene oxides and hydrochloric acid has been examined, for example, in the cases of p-mentadiene dioxide, a-3,4-epoxy-carane, and a-4,5-epoxycarane. Studies have been made of the reactions of steroid oxiranes with hydrochloric acid and hydrobromic acid. The acidic opening of compounds containing two oxirane rings can be carried out selectively and in good yield (Eq. 309). ... 

A noteworthy difference is observed in the condensation of thiosemicarbazide with aromatic a-halocarbonyl compounds in comparison to aliphatic a-halocarbonyl compounds. It has been found26 that the reaction of phenacyl bromide with thiosemicarbazide furnishes 5-phenyl-1,3,4-thiadiazin-2-amine together with a small amount of 5-phenylthiazolc-2-hydrazine, Similarly, the reactions of thiosemicarbazide with 2-bromo-l,2-diphenylethan-l-one,7 8,41 2-bro-mo-l-phenylpropan-l-one,10,41 and 2-bromo-l-phenylbutan-l-one 10,41 in ethanolic solution give 1,3,4-thiadizines. However, the main products are the thiazole-2-hydrazine derivatives (cf. Houben-Weyl, Vol. E8b, p 72ff). The addition of an equimolar amount of 48% hydro-bromic acid results in the exclusive formation of the 1,3,4-thiadiazines 2 a, c, and d. When the condensations of thiosemicarbazide with 2-bromo-l,2-diphenylethan-l-one, 2-bromo-1-phenylpropan-l-one or 2-bromo-l-phenylbutan-l-one are performed in ethanol at room temperature, the S-(oxoalkyl)-isothiosemicarbazide hydrobromides are formed as open-chain intermediates and also undergo cyclization in ethanol upon addition of an equimolar amount of 48% hydrobromic acid to furnish 2 a, c, and d. 

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