Process for preparation of 1-methyl-6-[6-R2-5-methyl-8-(methylamino)-4-[(3aS, 6aS)-5-methyl-2, 3, 3a, 4, 6, 6a-hexahydropyrrolo [2, 3-c] pyrrol-1-yl]-9h-pyrido [2, 3-b] indol-3-yl]-4-oxo-1, 8-naphthyridine-3-carboxylic acid hydrochloride

The present invention relates to a process for the synthesis of compounds of formula (I) or diastereoisomers, pharmaceutically acceptable salts thereof, wherein R1 is hydrogen or halogen; r2 is hydrogen, halogen or cyano; n is 0 to 7, in particular n is 2 to 3, more particularly n is 2; the compound can be used for preventing and treating diseases caused by bacterial infection. 本发明涉及一种用于合成式(I)化合物或其非对映异构体、药用盐的方法，其中R1为氢或卤素；R2为氢、卤素或氰基；n为0至7，特别地n为2至3，更特别地n为2；其可用于预防和治疗由细菌感染引起的疾病。