DERIVATIVES OF 7-, 8-, 9-(SUBSTITUTED)-6-DEMETHYL-6-DEHYDROXY-TETRACYCLINES, METHODS OF THEIR SYNTHESIS, INTERMEDIATE COMPOUNDS AND A PHARMACEUTICAL COMPOSITION Russian patent published in 1999 - IPC

FIELD: organic chemistry, antibiotics. SUBSTANCE: invention relates to derivatives of 7-, 8-, 9-(substituted)-6-demethyl-6-dehydroxy- tetracyclines of the formula (I) where X - halogen; R and R¹ are similar or distinct and mean H, NH₂, halogen, NR²R³ and when R and R¹ is NR²R³ and R² is H then R³ - methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methyl- propyl, 1,1-dimethylethyl; when R² - methyl, ethyl then R³ is methyl, ethyl, n-propyl, 1-methylethyl, n-butyl, 1-methyl- propyl, 2-methylpropyl; when R² is n-propyl then R³ is n-propyl, 1-methylethyl, n-butyl, 1-methylpropyl, 2-methyl- -propyl; when R² is 1-methylethyl then R³ is n-butyl, 1-methylpropyl, 2-methylpropyl; when R² is n-butyl then R³ is n-butyl, 1-methylpropyl, 2-methylpropyl; when R² is 1-methylpropyl then R³ is 2-methylpropyl; when R and R¹ are NR²R³ and R² - H then R³ is -CO-R⁴ where R⁴ - H, NH₂, mono-(C₁-C₆)-alkylamino-groups, diastereoisomers and enantiomers of mono - (C₁-C₆) - alkylamino - group; or R³ is di-(C₁-C₆)-alkylamino-group. Compounds are used as a pharmaceutical composition showing antibacterial activity. EFFECT: improved method of synthesis, enhanced effectiveness. 7 cl, 3 dwg, 3 tbl, 49 ex