关键词: 6-氯嘌呤, 2-氟腺嘌呤, 硝化, 氟代, 合成, 溶剂萃取

Abstract: The conventional synthesis of 2-fluoroadenine suffers from dangerous diazo reaction,expensive starting materials,low total yields and small scales,which limit the further application of 2-fluoroadenine. In order to overcome the preceding problems,a new method for the synthesis of 2-fluoroadenine from more commercially available 6-chloropurine was developed. The key intermediate 6-chlro-2-nitro-9-pyranylpurine was obtained from N9-pyranyl protected 6-chloropurine with a yield of 85% in butyl ammonium nitrate and trifluoroacetic anhydride and using CH₂Cl₂ as solvent. Then,6-chlro-2-nitro-9-pyranylpurine reacted with NH₄F with a yield of 82% in DMF followed by the ammonolysis in NH₃/CH₃OH solution. Finally,2-Fluoroadenine was obtained with a total yield of 58% through such a 4-step process. Chromatography was not necessary in the separating and purifying steps. The effects of protecting groups and reaction scales were investigated. The presented method avoided the toxic regents and expensive substrates and was simpler and safer,showing better practical application prospect.

Key words: 6-chlropurine, 2-fluoroadenine, nitration, fluorination, synthesis, solvent extraction