Synthesis and In Vitro Antibacterial Evaluation of Some Novel Annulated Quinazolinone Derivatives

Abstract

A series of novel substituted quinazoline derivatives are synthesized. Antibacterial tests demonstrate their high activity against Gram-positive and Gram-negative bacteria. 3-[4-(2-Bromoacetyl)-phenyl]-2-phenylquinazolin-4(3H)-one 2 and 3-oxo-3-{[4-(4-oxo-2-phenylquinazolin-3(4H)-yl]phenyl}propanenitrile 3 are used as intermediates in the synthesis of functionalized heterocyclic derivatives such as 3-[4-(2-amino-thiazol-5-yl)phenyl]-2-phenylquinazolin-4(3H)-one 4, Schiff base 5, 3-{5-(4-[4-oxo-2-phenylquinazolin-3(4H)-yl]phenyl)thiazol-2-yl}-2-phenylthiazolidin-4-one 6, and N-phenyl acetohydrazonoyl derivatives 7a, 7b. The latter react with ethyl cyanoacetate with formation of 9a, 9b. Chalcone 10 is the key intermediate in the synthesis of N-acetylpyrazole derivative 11 and 1-thiocaramoyl pyrazole derivative 12. Treatment of 12 with chloroacetyl chloride and compound 2 leads to formation of compounds 13 and 14, respectively. Treatment of compound 3 with phenyl isothiocyanate affords the corresponding quinazolin-3(4H)-yl acrylonitrile derivative 15, which reacts with phenyl hydrazine to give the corresponding product 16. The synthesized compounds are characterized by IR, MS and ¹H NMR spectra.