Anellation and Ring Transformations of Push-pull-functionalized Deoxypyranosiduloses

Reaction of (E)-3-aminomethylene-α-D-erythro-hexopyranosid-2-ulose 5 with substituted 5- aminopyrazoles afforded the pyrano-anellated pyrazolo[1,5-a]pyrimidines 8. The treatment of the corresponding (E)-2-aminomethylene-α-D-erythro-hexopyranosid-3-ulose 6 with 5-aminopyrazoles and (benzimidazol-2-yl)acetonitrile yielded in a ring transformation process the D-erythronoyl-pyrazolo[ 1,5-a]pyrimidine-3-carbonic acid derivatives 10 and D-erythronoyl-pyrido[1,2-a]benzimidazole- 4-carbonitrile (12), respectively