Synthesis of biologically active hydrazides and their derivatives

ABSTRACT

4-methoxy-[II a] and 4, 7-dimethoxy-6-hydroxybenzofuran-5-carboxylic acid [II b] give the esters [III a-c] upon treatment with diazomethane. IIIa and IIIb form the hydrazides [IV a-b] which on benzoylation in pyridine give the N-benzoyl derivatives [V a-b]. Cyclization of Va, b with phosphoryl chloride leads to the 2-phenyl- 5-substituted-1, 3, 4-oxadiazole derivatives [VI a, b]. Schotten- Baumann benzoylation of IVa affords the O-N-dibenzoyl derivative [VII]. The hydrazide [IVa] condenses with aromatic aldehydes and ketones to form the corresponding hydrazones [VIII a-i]. Compounds IIIa, IVa, VIII b, c, e and i have been found to possess antiaflatoxigenic activity