Mohamed A. Abdo

Synthesis of Novel 3H-Quinazolin-4-ones Containing Pyrazolinone, Pyrazole and Pyrimidinone Moieties

The diazonium salt of 3-(4-aminophenyl)-2-methyl-3H-quinazolin-4-one (2a) and its 6-bromo derivative 2b reacted with some active methylene compounds, namely ethyl acetoacetate (3), ethyl cyanoacetate (4) and acetylacetone (5), to afford the corresponding hydrazono quinazolinone derivatives 6-8. Treatment of 6a,b with hydrazine hydrate or phenyl hydrazine in refluxing ethanol afforded the corresponding pyrazolin-5-one derivatives of 3H-quinazolin-4-one 9a-d. Cyclization of 7a,b with hydrazine hydrate yielded the corresponding products 10a,b. Reaction of 8a,b with phenyl hydrazine or with urea afforded the corresponding derivatives 11a,b and 12a,b, respectively. Compounds 6-12 were identified by C,H,N analysis, IR, 1H-NMR, 13C-NMR and mass spectroscopy.

Synthesis and antiviral evaluation of some new glycosylthioureas containing a quinazolinone nucleus.

ABSTRACT A new synthesis of glycosylthioureas containing a quinazolinone nucleus is described utilizing per-O-acetylglycopyranosylisothiocyanates and several aminoquinazolinones as starting compounds. Structural proofs of these compounds are provided from elemental analyses, IR, 1H and 13C NMR spectra and mass spectra. The biological activity of these compounds has been studied.

Regiospecific electrophilic substitution of aminoquinazolinones: directed lithiation of 3-(pivaloylamino)- and 3-(acetylamino)-2-methylquinazolin-4(3H)-ones

The 2-methyl group in 3-(pivaloylamino)- and in 3-(acetylamino)-2-methyIquinazolin-4(3H)-ones has been lithiated with butyllithium. The lithium reagents thus obtained react with a variety of electrophiles (benzophenone, methyl iodide, D2O, cyclohexanone, acetophenone, phenyl isocyanate) to give the corresponding substituted derivatives in very good yields. The amide group has been cleaved in good yield under basic conditions for one model case to provide convenient access to 3-amino-2-ethylquinazolin-4(3H)- one. The NMR spectra of the 2-substituted 3-acylaminoquinazolin-4(3H)-ones show diastereotopism of the CH2 group at position 2.