Synthesis Reactions and Biological Evaluation of Some New Naphtho21-bfuran Derivatives Bearing a Pyrazole Nucleus

摘要

Vilsmeier formylation of 2-(1-phenylhydrazonoethyl)naphtho[2,1-b]furan (>2) gave 3-naphtho[2,1-b]furan-2-yl-1-phenyl-1H-pyrazole-4-carbaldehyde (>3), which was reacted with C- and N-nucleophiles to afford naphthofuranpyrazol derivatives >4-8. Treatment of 2-[(3-(naphtho[2,1-b]furan-2-yl)-1-phenyl-1H-pyrazol-4-yl)methylene]-malononitrile (>4a) with reactants having active hydrogen and Et3N gave the corresponding pyrazoline, pyran and chromene addition product derivatives >10, >12 and >13, consisting of three different connected heterocyclic moieties. Reaction of 1-((3-(naphtho[2,1-b]furan-2-yl)-1-phenyl-1H-pyrazol-4-yl) methylene)-2-phenylhydrazone (>6b) with AcONa and ethyl bromoacetate or chloroacetone afforded the thiazolidinone and methylthiazole derivatives >14 and >15, respectively. In addition, intramolecular cyclization of >6d with Ac2O afford the corresponding 1,3,4-thiadiazol-2-yl acetamide derivative >16. The structures of the synthesized compounds were confirmed by IR, ¹H-NMR/¹³C-NMR and mass spectral studies. Compound >14 showed promising effects against the tested Gram positive and negative bacteria and fungi.