Inhibition of Ribonucleotide Diphosphate Reductase

5-Adenosylmethionine (SAM) is a donor of a methyl group in numerous biological methylations. It is first transformed into 5-adenosylhomocysteine (SAH), then into adenosine and homocysteine by SAH hydrolase. 

SAH that is produced by SAH hydrolase regulates back the methylase that generates it. By regulating the level of SAH, SAH hydrolase indirectly controls the potential of methylation. This is the reason why inhibitors of SAH hydrolase may exhibit antiviral activity they allow the accumulation of SAH. As a consequence, methylation of messenger RNAs that are required for virus replication is inhibited. 

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Deoxy-2 -difluoromethylene nucleosides, also of interest in connection with the inhibition of ribonucleotide diphosphate reductase, have been made by a modified Julia synthesis as outlined in Scheme 13 the cytosine analogue was also reported. 0 OEt... 

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