Separation of lutidines by enclathration

Abstract

Three related diol host compounds have been employed to separate lutidine isomers. Thirteen equimolar mixtures of the isomers were enclathrated by each of the host compounds in turn, and the results monitored by NMR. When the selectivity was poor, crystal structures of the host compounds with each of the single isomers and their mixture, were elucidated. By appropriate use of the three host molecules, it proved possible to separate each isomer. The selectivity trend is 2,3-LUT ≈ 3,4-LUT > 2,5-LUT > 2,4-LUT > 2,6-LUT.