Abstract
6,7-Dimethyl-3-formyl-4-hydroxycoumarin 1 was treated with triacetic acid lactone 2 in heating methanol to afford 8,9-dimethyl-3-acetoacetyl pyrano[3,2-c][1]benzopyran-2,5-dione 3. The compound 3 was transformed to pyrano pyrazole derivatives 4a-c by treatment with nitrogen bases such as hydrazine hydrate, phenylhydrazine and hydrazinobenzothiazole. The structure of all compounds was established on the basis of spectroscopic studies and screened for their antibacterial and anti-inflammatory activities.