- An efficient synthesis of 2-substituted 6-methylpurine bases and nucleosides by Fe- or Pd-catalyzed cross-coupling reactions of 2,6-dichloropurines
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Fe-catalyzed cross-coupling reactions of 9-substituted or protected 2,6-dichloropurines with 1 equiv of methylmagnesium chloride gave regioselectively 2-chloro-6-methylpurines in good yields. The same reactions with 3 equiv of methylmagnesium chloride or
- Hocek, Michal,Dvorakova, Hana
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p. 5773 - 5776
(2007/10/03)
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- Occurrence of the SNANRORC Mechanism in the Amination of 2-Substituted Purines with Potassium Amide in Liquid Ammonia
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The reactions of 2-chloro-, 2-fluoro- and 2-(methylthio)purine with potassium amide in liquid ammonia lead to the formation of 2-aminopurine.When these reactions are carried out with 15N-labeled potassium amide, ring-labeled 2-aminopurine is found.This demonstrates that a ring opening occurs during the amination.Formation of an anionic ? adduct at position 6 is proven by low-temperature NMR spectroscopy, and evidence is obtained for the formation of an open-chain intermediate, although this intermediate could not be isolated in a pure state.Reaction of the open-chain intermediate with hydriodic acid gives the thus far unknown 2-iodopurine. 2-Chloro-6-phenylpurine also reacts via ring opening into 2-amino-6-phenylpurine.However, 2-chloro-6-methyl- and 2-chloro-6,8-di-tert-butylpurine are found to be unreactive.
- Kos, Nico J.,Plas, Henk C. van der
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p. 2942 - 2945
(2007/10/02)
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