Transformation von Uridin‐ zu Cytidinderivaten durch selektive Aminierung

Transformation of Uridine Derivatives into Cytidines via Selective Amination The synthesis of some 5‐fluorosubstituted cytidine 2 derivatives via amination of corresponding uridine derivatives 1 is described. 5‐Substituted 4‐tetrazolo pyrimidinone derivatives 5 are key intermediates in the procedure. The method used is extended to other fluorinated starting materials, e.g. fluorinated uridinedinueleotides 7 or 2′‐deoxy‐2′‐fluorouridine 9. The fluoro containing products are easily available by fluorination with elemental fluorine or hydrogene fluoride.