Carbon-13 NMR Spectra of Bromine-containing Esters

Article abstract of DOI:10.1002/mrc.1270130610

13CHBrCOOR fragments of bromine-containing mono- and dicarboxylates show 13C NMR signals in the range 38-45 ppm, at 12-15 ppm to high field of their chloro analogues.The introduction of one bromine atom into the α-CH2 group causes a 6-13 ppm shift of the carbon signal, depending on the type of ester.The replacement of H with Br in 13C2H2(COOR)2 has only a negligible influence on the 13CH2 signal position.The 13CBr2COOR fragment signals appear in the range 40-54 ppm. 13C NMR data, including the chemical shift values, signal multiplicities and spin-spin couplings, make possible the identification of isomers present in isomer mixtures of bromine-containing esters.The 13COOR chemical shifts of diastereomers of α,β-dibromoesters differ noticeably from each other, and the 13C NMR spectra can thus be used to supply preliminary information about the stereochemistry of bromine addition to α,β-unsaturated acids.