Abstract
A series of arylaldehydes and acetophenone when treated with 1,2-ethanediamine afford the bis-Schiff bases N,N'-bis(arylidene)-ethane-1,2-diamines 1-8, N,N'-bis(arylmethylene)-ethane-1,2-diamines 9-10 and the N,N'-bis(1-phenylethylidene)-ethane-1,2-diamine 11. The bis-imines 1-11 on regiospecific 1,3-dipolar cycloaddition with [(4-chlorophenyl)methyldyne]azans oxide, prepared in situ, afford the expected new 1,2,4-bis-oxadiazolines 12-22. The target molecules have been identified on the basis of satisfactory analytical results and characterized by spectroscopic means (H-1 NMR, C-13 NMR, UV, IR, HRMS and elemental analyses). All the previously unknown compounds 12-22 have been screened for their antifungal activity towards Trichoderma harzianum, Botrytis cinerea, Fusarium sambucinum and Penicillium sp. using the disc diffusion method. Applied at two concentrations, some of these bis-oxadiazolines exhibit an interesting inhibitory effect against the fungi tested. It is found that compounds, possessing an NO2 group on their aromatic ring, exhibit variable antifungal activity against B. cinerea depending on NO2 position. In fact, the inhibitory activity has been found to be increased when the NO2 group is situated in the meta position.