Synthesis and characterization of some nitrogen heterocycles from d‐galactose derivatives

The tetrazoles 5‐(6′‐acetamido‐6′‐deoxy‐1′,2′:3′,4′‐di‐ O ‐isopropylidene‐D‐ glycero ‐α‐D‐galactohexopyranos‐6′‐yl)tetrazole ( 1 ) and 5‐(6′‐acetamido‐6′‐deoxy‐1′,2′:3′,4′–di‐ O ‐isopropylidene‐L‐ glycero ‐α‐D‐galacto‐hexopyranos‐6′‐yl)‐tetrazole ( 2 ) were synthesized by the 1,3‐dipolar cycloaddition reaction of the epimeric α‐acetamidonitriles 5 and 6 , respectively, with sodium azide. Reaction of tetrazole 1 with acetic anhydride in the presence of pyridine afforded the N ‐acetyl‐1,3,4‐oxadiazole derivative 3 and the N‐ acetylacetamido‐1,3,4‐oxadiazole derivative 7 . The N ‐acetylacetamido‐1,3,4‐oxadiazole derivative ( 8 ) was isolated when the tetrazole 2 was allowed to react under the same conditions. The physical and spectroscopic data of the five new compounds 1, 2, 3, 7 and 8 are presented.