Mycobacterium tuberculosis thymidine monophosphate kinase inhibitors: Biological evaluation and conformational analysis of 2 ‘- and 3 ‘-modified thymidine analogues

Eur. J. Org. Chem., 2003: 2911–2918. doi: 10.1002/ejoc.200300177

Mycobacterium tuberculosis thymidine monophosphate kinase (TMPKmt) has recently been introduced as a potential target for the structure-based design of anti-tuberculosis drugs. Based on the TMPKmt X-ray structure and previous S.A.R. studies, we synthesised the nucleoside analogues 3a−b, 6a−b, 7a−b, and 8a−b, modified in 2′- and 3′-position of the ribofuranose ring moiety. To our surprise, these analogues showed only moderate binding affinity (i.e. K_i between 118 and 1260 μM). This prompted us to investigate the conformational features of these nucleosides. We concluded that compounds of this series, especially 8a−b, are strongly biased towards the “Northern” furanose ring conformation, whereas X-ray crystallography reveals a preference of TMPKmt for the opposite “Southern” conformers. This paper covers the synthesis, biological evaluation and conformational features (i.e. preferred ring puckering) of the 2′- and 3′-modified dT analogues.