REACTION OF HYDRAZINE HYDRATE AND HYDRAZINE HYDROCHLORIDE WITH DIBENZOYLMETHANE AND FLAVONE: ROLE OF SOLVENT AND pH ON FORMATION OF PRODUCTS

Selection of solvent and pH of the reaction mixture are important for the formation of desired products. Ethanol and DMF as reaction medium, pH was kept either basic (pH 10) or acidic (pH 4). Hydrazine hydrate and hydrazine hydrochloride in ethanol gave different product with dibenzoylmethane. Flavones with hydrazine hydrate in ethanol gave a product similar to that obtained by the action of hydrazine hydrate on dibenzoylmethane in ethanol. Flavones with hydrazine hydrochloride in DMF only to give flavone hydrazones. Dibenzoylmethane with hydrazine hydrate in ethanol gave pyrazole, but with hydrazine hydrochloride in ethanol gave flavone hydrazones . Flavones with hydrazine hydrochloride in DMF gave flavone hydrazones. With hydrazine hydrate (pH 10) dibenzoylmethane and flavone gave pyrazole while dibenzoylmethne with hydrazine hydrochloride (pH 4) gave flavone hydrazone.