Synthesis and characterization of some new 4(3H)-quinazolinones

The synthesis and characterization of a series of new 4(3H)-quinazolinones is being reported. The new 4(3H)-quinazolinones have either one or two chlorine atoms in the benzene ring and a thiazol-5-yl or 1,3,4-thiadiazol-5-yl substituent in position 3. The new compounds were synthesized in a two-step procedure described before for a different series of compounds. Substituted chloroanthranilic acids (or 3,5-dichloroanthranilic acid) and acetic anhydride yielded the intermediate 3,1-benzoxazin-4-ones which subsequently afforded the desired products by reaction with a substituted 2-aminothiazole or 2-amino-1,3,4-thiadiazole in the presence of dry pyridine. In addition to elemental analyses and melting points, the new compounds were characterized by their 1H and 13C nmr, ir, uv, and mass spectra. The new quinazoline derivatives are expected to be biologically active and will be tested for their potential anticancer and antiviral activity.