This is the first report on montmorillonite K-10 clay (nanoclay)-catalyzed,
domino reactions of unprotected d-glucose/d-xylose with amidines/guanidine
and an activated natural amino acid 2-phenyl-1,3-oxazol-5-one. The
procedure results in an efficient annulation of the iminosugar moiety
with functionalized pyrimidines in excellent yields (79-92%)
with high trans-diastereoselectivity
(>94%). The reaction is effected under solvent-free microwave
irradiation conditions via amidine/guanidine-driven coupling
and ring-transformation reactions in a one-pot procedure.
carbohydrates - mineral-catalyzed - amidines/guanidine - microwaves - ring transformation - pyrimidines