- An Unusual Oxidative Ring Transformation of Purine to Imidazo[1,5-c] imidazole
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(Equation presented) Reevaluation of products derived from 3, 9-dimethyluric acid in a chlorination-reductive dechlorinaton sequence has demonstrated unequivocally that they are not purines. Spectroscopic and degradative evidence, in conjunction with position-labeling NMR studies, revealed an unprecedented oxidative ring transformation pathway involving the key purine-to-imidazo[1,5-c]imidazole rearrangement.
- Poje, Nevenka,Poje, Mirko
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p. 4265 - 4268
(2007/10/03)
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- Purines XIV. [1]. Reactivity of 8-Bromo-3,9-dimethylxanthine Towards Some Nucleophilic Reagents
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The reactivity of 8-bromo-3,9-dimethylxanthine (6) towards a variety of nucleophilic reagents has been investigated. Nucleophilic displacements take place easily with aliphatic mercaptans and aliphatic alcohols, whereas aliphatic amines required more severe conditions. Prolonged heating of 6 with amines causes a new type of rearrangement from 3,9- to 3,7-dimethylxanthines due to a 1,3-sigmatropic shift of the N(9)-methyl group.
- Youssef, Shaker,Pfleiderer, Wolfgang
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p. 949 - 954
(2007/10/03)
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