| abstract |
1469468 Tetracyclines HOECHST AG 4 Nov 1974 [3 Nov 1973] 47520/74 Heading C2C [Also in Division A5] Novel tetracyclines of the general formula wherein R 1 is a C 1-4 alkyl group, each of R 2 and R 3 is a hydrogen atom or a C 5-7 cycloalkyl group or a C 1-6 alkyl group optionally substituted by at least one substituent selected from hydroxy, di-C 1-4 alkylamino, di-C 1-4 alkylcarbamoyl, C 1-4 alkoxy-carbonyl, phenyl and heterocyclic groups and carboxyl groups, in which case the alkyl group may also be substituted by an amino group, or R 2 and R 3 , together with the adjacent nitrogen atom, form a 5- or 6- membered ring which may include an additional nitrogen or oxygen atom and which is optionally substituted by at least one substituent selected from C 1-4 alkyl, C 1-4 hydroxyalkyl, carboxy- C 1-4 alkyl, hydroxy and carboxyl groups, each of R 4 and R 5 is a hydrogen atom or hydroxyl group, R 6 is a hydrogen atom or methyl group, or R 5 and R 6 together form a methylene group, and R 7 is a hydrogen, chlorine or bromine atom or a dimethylamino or diethylamino group, and salts thereof are prepared by reacting in any order (a) a tetracycline of the general formula (b) a glyoxylic acid ester of the general formula OCH-CO 2 R 1 or its hemiacetal of the general formula HOCH(OR 8 )CO 2 R 1 , wherein R 8 is a C 1-4 alkyl group, and (c) a compound of the general formula R 2 -NH-R 3 , followed optionally by salification. |