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A number of new 4-anilinoquinazolines were synthesized starting from 6,7,8-trifluoro-2-(methyl­sulfanyl)quinazolin-4(3H)-one. Reactions of the title compounds with cyclic secondary amines involved substitu­tion of the 7-fluorine atom with retention of the methylsulfanyl group on C2. 6,7,8-Trifluoro-4-(2-me­thoxyanilno)-2-(methylsulfanyl)quinazoline showed in vitro tuberculostatic activity with a minimum inhibitory concentration of 1.5 μg/mL.

New 2-(5-aryl-6-R-3-phenyl-5,6-dihydro-4H-1,2,4,5-tetrazin-1-yl)-1,3-benzothiazoles were synthesized from the corresponding formazans by alkylation and subsequent cyclization of N-alkyl derivatives. The products were characterized by 1H and 13C NMR, IR, and mass spectra and X-ray diffraction data. Electrochemical properties and antioxidant activity of the synthesized benzothiazole derivatives were studied.

New 2-(1-methyl-1H-pyrrol-2-yl)- and 2-(1-methyl-1H-indol-3-yl)-5-fluoro- and -6,7,8-trifluoro-1,3-benzothiazin-4-ones have been synthesized in high yields by reaction of o-fluorobenzoyl isothiocyanates with C-nucleophilic 1-methyl-1H-pyrrole and 1-methyl-1H-indole, followed by base-catalyzed cyclization. The products were characterized by 1H, 13C, and 19F NMR and mass spectra and X-ray diffraction data.

trans-2-Styryl-substituted 3H-, 3-phenyl-, and 3-naphthylquinazolin-4-ones and their 6,7-difluoro derivatives were synthesized by condensation of appropriate 2-methylquinazolin-4-ones with aromatic aldehydes or by the transformation of the heterocycle of 2-methyl-3,1-benzoxazin-4-one under the action of benzylidenephenylamines.

5- and 7-Fluoro-substituted quinazolines and 1,3-benzothiazin-4-ones were synthesized starting from 2-amino-6-fluorobenzonitrile and mono- and difluoro-substituted benzoic acid derivatives. The reactivities of di- and tetrafluoro-substituted benzoyl chlorides and benzoyl isothiocyanates in cyclocondensations leading to fluorinated quinazolines and 1,3-benzothiazines were compared.

Reactions of fluorine-containing 3,1-benzoxazin-4-ones with ammonium acetate, hydrazine, and heteroaromatic amines gave new 3H-, 3-amino-, and 3-hetarylquinazolin-4-ones, respectively. Differences in the conditions of formation of benzoxazinones from anthranilic acids with different fluorination patterns and in the reactions of fluorinated 3,1-benzoxazinones with nitrogen-centered nucleophiles were revealed.