Indazoles are a class of organic heterocyclic compounds, also known as 1,2-diazaindene and benzopyrazole. Indazole is a good bioisomer of phenol, which is more lipophilic than phenol and less prone to phase I and II metabolism. Indazole derivatives have a wide range of biological activities, and it has been confirmed that indazole compounds have anti-tumor, analgesic, anti-inflammatory and other drug activities. Anticancer is the most important application field of indazole drugs. Renal cell carcinoma, solid tumor, nausea and vomiting caused by chemotherapy and leukemia are the main indications of this structural backbone drug.
Dioxolane is a heterocyclic acetal with the formula (CH2)2O2CH2. It is related to tetrahydrofuran by exchanging an oxygen for the CH2 group. The isomer 1,2-dioxolane (in which the two oxygen centers are adjacent) is a peroxide. 1,3-Dioxolane is used as solvent and comonomer in polyacetal. The dioxolane-type and their hydrogenolysis can provide very valuable partially protected building blocks either for oligosaccharide syntheses or sugar transformations.