There is a great interest in the study of photooxidations with singlet oxygen due to the important role which play in oxidative damage to DNA and its biological consecuences in living cells. Several products of the photooxidations of nucleic acid derivatives have been reported and intermediates such as endoperoxides have been proposed to account for them. This endoperoxides are the products of singlet oxygen (4+2) cycloadditions.
The (4+2) cycloaddition reaction of singlet oxygen to 1,3-dienes has been extensively studied from both synthetic and mechanisthic points of view and this is a important field of research at Professor Adam's group. However, there is a few examples of singlet oxygen photooxidations of azadienes in spite of the fact that (4+2) cycloadditions of singlet oxygen to a 2-azadiene moiety present in the molecule is suspected to be the first step in the most of the photooxidations proccess of the nitrogenated bases in DNA or of imidazole residues present in the polypeptide chain of several enzymes like insuline and ribonucleasa.
The objetive of the research work will be:
(a) The study of the (4+2) cycloadditions of singlet oxygen to 2-azadienes. (b) The use of the obtained products in Synthetic Chemistry. (c) The study of the 3,14-facial selectivity of this kind of cycloadditions with different 3,14-faces
Two kinds of 2-azadienes are proposed for its photooxidations: 1. 3,3-disubstituted-3H-pyrroles