Characterization and quantitation of 3-alkylthymidines from reactions of mutagenic propylene oxides with thymidine.

Thymidine was reacted in methanol with four epoxides of varying mutagenicities: propylene oxide, glycidol, epichlorohydrin and trichloropropylene oxide. A single product was detected with each epoxide, and these products had the same retention times on silica high pressure liquid chromatography (HPLC). UV spectra of the products identified them as 3-alkylthymidines, and this was confirmed by infrared (IR) and nuclear magnetic resonance (NMR) spectra. Mass spectra (MS) analysis showed the products to be consistent with attachment at the least substituted carbon of the epoxide. Formation of 3-alkylthymidines correlated to Taft sigma electron withdrawing values for the substituents on the epoxides and mutagenicities in strain TA100 of the Ames Assay.