Three-component coupling strategy for the expeditious synthesis of novel 4-aminobenzoxazinone N-nucleosides

One-pot montmorillonite K-10 clay-supported three-component reactions of substituted salicylaldehydes, ribosyl/deoxyribosylureas and ammonium acetate expeditiously yield the novel N-nucleosides, 4-amino-3,4-dihydro-3-(β-d-ribo- or β-d-2′-deoxyribofuranosyl)-2H-benz[e]-1,3-oxazin-2-ones, via cycloisomerisation of an aldimine intermediate under solvent-free microwave irradiation conditions.