A set of nonpolar thymidine nucleoside analogues with gradually increasing size.

[structure: see text] We describe a series of nonpolar nucleoside analogues having similar shapes and gradually increasing size. The structure of the nucleobase thymine was mimicked with toluene derivatives, replacing O2/O4 with hydrogen, fluorine, chlorine, bromine, and iodine. Glycosidic bonds were formed by reactions of lithiated 2,4-dihalotoluenes with a deoxyribonolactone derivative. Structural analysis by NMR showed similar conformations across the series. The compounds are useful for study of the biological recognition of nucleotides and nucleic acids.