FIELD: organic chemistry, biochemistry, medicine, pharmacy. SUBSTANCE: invention describes novel benzoxazinone compounds of the general formula (I) 
where X means halogen atom; X1 means trihalogenmethyl; Z means O; R means: (a) unsubstituted C1-8-alkyl or that substituted with halogen atom, 5-membered saturated monocyclic ring comprising 1-2 heteroatoms taken among nitrogen and oxygen atoms; (b) unsubstituted C2-4-alkenyl or that substituted with C1-4-alkoxy-group; or (c) unsubstituted C2-5-alkynyl or that substituted with C3-6-cycloalkyl, hydroxy-group, di-(C1-2-alkyl)-amino-group, C1-4-alkoxy-group, unsubstituted phenyl of phenyl substituted with C1-4-alkoxy-group, nitro-group, CN, 5-membered saturated monocyclic ring comprising 1-2 heteroatoms taken among nitrogen and oxygen atoms, or its pharmaceutically acceptable salt. Compounds of the formula (I) can be used in aims for inhibition of activity of HIV reverse transcriptase (including its resistant forms) and also for aims of prophylaxis and treatment of HIV-infections and AIDS. The indicated compounds can be used both as such and as their pharmaceutically acceptable salts or as components of pharmaceutical compositions used both separately and in combination with other antiviral agents, immunomodulating agents, antibiotics or vaccines. Invention discloses also methods of treatment of AIDS, prophylaxis and treatment of HIV-infections and method of synthesis of (-)-6-chloro-4-cyclopropylethynyl-4-trifluoromethyl-1,4- -dihydro-2H-3,1-benzoxazine-2-one. EFFECT: improved method of synthesis, valuable medicinal properties. 13 cl, 5 tbl, 6 ex
