Abstract
An efcient and rapid regiospecifc approach for the synthesis of cyclic and acyclic nucleosides of 2-oxonicotinonitriles was performed. Whereas, glycosylation of 2-oxonicotinonitriles 1a, b with peracetylated sugars (namely, peracetylated glucose, galactose
and ribose) under MWI tolerated exclusively the desired N-nucleosides 2a, b, 4a, b and 6a, b in signifcant yields (75–86%) and
in short reaction time (5–7 min.). The same products were obtained under the conventional conditions, using halo-sugar with low
yields in hard conditions. Similarly, the acyclic nucleosides 8a, b and 9a, b were obtained under MWI and conventional conditions
via reaction of 1a, b with 4-bromo butyl acetate and 2-acetoxyethoxymethyl bromide. Finally, deprotection of the latter blocked
N-nucleosides was performed via treatment with aqueous methanolic solution containing a catalytic amount of triethyl amine to
give the desired free nucleosides 3a, b, 5a, b, 7a, b, 10a, b and 11a, b, respectively. The free nucleosides (3a, b, 5a, b, 7a, b and
11a, b) were evaluated against Gram (+ve) bacteria, Gram (–ve) bacteria and one pathogenic Fungi namely, Aspergillus flavus.
Good results were obtained for compounds 7a, b and 11a, b compared with the used standard drugs (Cefotaxime and Dermatin). |
