Procédé de préparation de nouveaux dérivés de la tétracycline

A method for preparing new compounds comprising substituted deoxytetracyclines having the formula I. ** (See formula) ** and salts by addition of acid thereof, wherein R1 and R2 are members of the group consisting of hydrogen, nitro, amino, cyano and halogen, except that R1 and R2 can not both be hydrogen or halogen and, when R1 is halogen, R2 can not be hydrogen, and vice versa, R3 is hydrogen or methyl and R4 is hydrogen or hydroxyl, characterized in that a compound of general formula I is reacted where R1 and/or R2 are hydrogen, or a salt by addition of acid thereof, with a nitrating agent and, subsequently, if desired, performing any of the following operations in any desired order: a) halogenating a compound of formula I; b) reducing the nitro group of a compound of formula I to an amino group, and c) nitrating a compound of formula I. (Machine-translation by Google Translate, not legally binding)