Mild and regioselective nitration of 1-deazapurine nucleosides using TBAN/TFAA

To obtain selectively functionalized 1-deazapurine nucleosides, the nitrati ng mixture tetrabutylammonium nitrate/trifluoroacetic anhydride (TBAN/TFAA) has been studied. This mixture demonstrated several merits: the use of an easy to handle reagent, mild reaction conditions and high selectivity for n itration in the pyridine ring. Nitration occurred at the alpha or beta-posi tion with respect to the pyridine nitrogen atom, depending on the substitue nts in the ring. Electron withdrawing substituents in the pyridine ring sho wed a positive effect on this nitration. (C) 2000 Elsevier Science Ltd. All rights reserved.