Fluorinated Furanoses and Nucleosides

2 MONO- AND DIFLUORINATED ANALOGUES OF SUGARS 6.2.1 Fluorinated Furanoses and Nucleosides 

Antiviral and antitumor properties of nucleoside analogues have given rise to a considerable number of smdies. These compounds are often inhibitors of the enzymes that are involved in the biosynthesis of nucleosides, in DNA replication and transcription phenomena, and in metabolic transformation (e.g., phosphorylation of a nucleoside). For these reasons, fluorinated analogues of nucleosides have been especially studied, and this phenomenon has increased due to the search for anti-HIV drugs. 

Fluorination of a nucleoside concerns either the base or the furanose moiety. This chapter mostly focuses on nucleosides that are fluorinated on the furanose osidic moiety. A short summary of nucleosides that are fluorinated on the base moiety is given at the end of this section, and a more extensive overview is given in Chapter 7 (enzyme inhibitors). 

One of the rare fluorinated products found in nature is a fluorinated nucleoside called nucleocidine (4 -fluoro-5-(9-sulfamoyladenosine). This compound has been isolated from microbial cultures (cf. Chapter 4).  

or5-Huorodeoxyfuranoses, 2- or 3-fluoro 2,3-dideoxyfuranoses, unsaturated 2- and 3-fluoro-, and corresponding difluorofuranoses have all been widely studied. In this section, we consider the entire fluorinated furanose family, since introduction of fluorine is often done on any other of the cited substrates. 

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