Awater-insoluble hydrocarbon a decolorizes a solution of br2 in ch2cl2. the base peak in the ei mass spectrum of a occurs at m/z = 67. the proton nmr of a is complex, but integration shows that about 30% of the protons have chemical shifts in the δ 1.8–2.2 region of the spectrum. treatment of a successively with oso4, then periodic acid, and finally with ag2o, gives a single dicarboxylic acid b that can be resolved into enantiomers. neutralization of a solution containing 100.0 mg of b requires 13.7 ml of 0.100 m naoh solution. compound b, when treated with pocl3, forms a cyclic anhydride. give the structures of a and b, omitting stereochemistry.