Ultra-violet Irradiation of 1,3-Dimethylthymine

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WHEN 5,6-unsubstituted pyrimidines (I) such as uracil, uridine and 1,3-dimethyluracil are irradiated with ultra-violet light, the absorption spectra gradually decrease with a simultaneous increase in end absorption. These spectra can be reversed to the original by acid, alkali or heat1. However, compounds substituted in the 5-position (II), such as thymine, thymidine and 1,3-dimethyl-thymine, do not show reversal under similar conditions. Most investigators have suggested that this difference may be due to totally different photochemical reaction mechanisms in the two cases2.

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WANG, S. Ultra-violet Irradiation of 1,3-Dimethylthymine. Nature 184, BA59–BA61 (1959) doi:10.1038/184059a0b

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