In the reaction of 2-amino-1-bromopropane hydrobromide (11) with 1 equiv. of sodium thiosulfate, the formation of only one product, 2-aminopropane-l-thiosulfuric acid (IV), is detected. Similar treatment of l-amino-2-bromopropane hydrobromide (I) yields two products, namely, 1-aminopropane-2-thiosulfuric acid (111) and the rearranged product, IV. In order to determine whether an ethylenimonium ion is an intermediate in the formation of ...