Photochemical substitution thymine

As a consequence of photodamage to DNA there is still considerable interest in the photochemical dimerization of pyrimidine derivatives. Thus, the synthesis of the pyrimidine dimers (157), (158) and (159) has been carried out by irradiation of the pyrimidine derivative (160). Sugiki et al. have studied the photochemical dimerization of the long-chain substituted thymine derivatives (161). The results of the measurement of the reduction potentials of thymine and cytosine cyclobutane dimers have been reported. In addition the electron-transfer-induced ring cleavage by electron donation from suitable sensitizers of the adducts (162) and (163) has also been examined. Calculations have been carried out on the photo-induced repair mechanism in DNA both by direct irradiation and by the use of SET induced photocleavage. ... 

Synthesis of 4(6)-amino-l,3,5-triazine-2-ones and 2-thiones starting from benzotriazole derivatives has been reported <01JOC6797>. The first template photochemical synthesis of a 1,3,5-triazine derivative as a receptor capable of differentiating between thymine and uracil has been described <01CC1446>. A new solid phase synthesis of trisubslituted 6-amino(substituted)-2,4-dioxo-3,4-dihydro-l,3,5-triazines from a resin-bound amine component has been reported <01JCO278>. The synthesis of thirteen lris(azol-l-yl)-13,5-triazines, as a new class of multidentatc ligands, has been described <01H(55)905>. Tris(pyrazolyl-13,5-triazincs) 14 have been prepared by cyclotrimerization of aromatic nitriles, in piperidine and in solvent-free conditions <01T4397>. 

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