Synthesis and Characterization of 9(10)-Bromo-9-octadecenoic Acids

9(10)-Bromo-cis-9-octadecenoic acid, m. p. 36.7° C, was prepared by dehydrobromination of threo-9,10-dibromo-stearic acid with bases and by polar addition of hydrogen bromide to stearolic acid. The trans isomer, m. p. 6°–8° C, was obtained from the corresponding erythro-dibromide. Both compounds were characterized by IR and NMR spectroscopies and a reaction scheme for their formation by dehydrobromination is suggested.