Glycerol-1,2-carbonate: A mild reagent for the N-glycerylation of pyrazolecarboxylates

In this study, glycerol-1,2-carbonate was employed as a convenient reagent for the synthesis of more complex pyrazole-containing heterocyclic systems. 3-O-Tosylated glycerol-1,2-carbonate (TGC) was used for alkylation of NH-pyrazolecarboxylates. The obtained N-glycerylated pyrazoles were further treated with diverse nucleophiles for 2-oxo-1,3-dioxolane ring cleavage. The synthesized 1-(2,3-dihydroxypropyl)-1H-pyrazole-5-carboxylates were subsequently hydrolyzed and treated with p-toluenesulfonic acid, yielding a series of 6-(hydroxymethyl)-6,7-dihydro-4H-pyrazolo[5,1-c][1,4]ox-azin-4-ones.