Chapter 19, Problem 19.57SP

An unknown compound shows a weak molecular ion at m/z 87 in the mass spectrum, and the only large peak is at m/z 30. The IR spectrum follows. The proton NMR spectrum shows only three singlets: one of area 9 at δ0.9, one of area 2 at δ1.0, and one of area 2 at δ2.4. The singlet at δ1.0 disappears on shaking with D₂O. Determine the structure of the compound, and show the favorable fragmentation that accounts for the ion at m/z 30.