Synthesis of some N-alkylated 1,2,4-triazoles, 1,3,4-oxadiazoles, and 1,3,4-thiadiazoles based on N-(Furan-2-yl-methylidene)-4,6-dimethyl-1H-pyrazolo- [3,4-b]pyridine-3-amine

N-(Furan-2-ylmethylidene)-4,6-dimethyl-1H-pyrazolo[3,4-b]pyridine-3-amine was prepared and alkylated with the corresponding halo compounds to afford N-alkylated products. 2-[3-(Furan-2-ylmethylideneamino)-4,6-dimethyl-1H- pyrazolo[3,4-b]pyridin-1-yl]acetohydrazide was converted into the key intermediate thiosemicarbazide, which undergoes cyclization reactions under acidic and basic conditions to give 1,2,4-triazole, 1,3,4-oxadiazole, and 1,3,4-thiadiazole derivatives. Condensation of the hydrazide with monosaccharide aldoses gave the corresponding sugar hydrazones, which on treatment with acetic anhydride readily undergo cyclization reaction to afford oxadiazoline derivatives.