Syntheses of Pyrazole Iso-C-Nucleosides

ABSTRACT

3-O-Benzyl-6-deoxy-1,2-O-isopropylidene-α-D-xylo-hexofuranos-5-ulose (1) and 3,6-dideoxy-1,2-O-isopropylidene-α-D-glycero-hex-3-enofuranos-5-ulose (6) reacted with carbon disulfide and methyl iodide under basic conditions to give the α-oxoketene-S,S-acetals 2 and 7, respectively. Treatment of 2 and 7 with hydrazine hydrate yielded the pyrazole derivatives 3 and 8, respectively.