Methods of preparing and purifying 9-nitrominocycline and 9-aminominocycline and salts thereof used in the process of making tigecycline, are disclosed. In one embodiment, the invention is directed to a method of preparing the compound of formula 1
or a pharmaceutically acceptable salt thereof, comprising:
(a) reacting nitric acid with the compound of formula 2,
or a salt thereof, to produce a reaction mixture comprising an intermediate; and
(b) further reacting the intermediate to form the compound of formula 1, wherein the intermediate is isolated from the reaction mixture, the method further comprising sparging with an inert gas prior to step (a).
本发明公开了制备和纯化9-硝基
氨基环霉素和9-
氨基
氨基环霉素及其盐,用于制备替吉奥环素的方法。在一种实施方式中,本发明涉及一种制备式1化合物或其药学上可接受的盐的方法,包括:(a)将
硝酸与式2化合物或其盐反应,以产生包含中间体的反应混合物;以及(b)进一步反应中间体以形成式1化合物,其中从反应混合物中分离出中间体,该方法在步骤(a)之前还包括用惰性气体通气。