Bromination of 3-methyl-2-butanone yielded two compounds, each having the molecular formula C5H9BrO, in a 95:5 ratio. The 1H NMR spectrum of the major isomer A was characterized by a doublet at δ 1.2 ppm (6 protons), a septet at δ 3.0 ppm (1 proton), and a singlet at δ 4.1 ppm (2 protons). The 1H NMR spectrum of the minor isomer B exhibited two singlets, one at δ 1.9 ppm and the other at δ 2.5 ppm. The lower field singlet had half the area of the higher field one. Suggest reasonable structures for these two compounds.