Multi-step one-pot process for the preparation of inter alia 7β-amino- and 7β-acylamino-3-substituted methyl-3-cephem-4-carboxylic acid derivatives starting from 7p-acylamino-3-methyl-3-cephem-4-carboxylic acid 1β-oxide derivatives, comprising a new process for deoxygenation of generally 7p-acylamino-3-cephem-4-carboxylic acid 1-oxide derivatives optionally substituted in the 7a-position, which can be applied as single step or can be incorporated in multistep processes without isolation of intermediates.
The deoxygenation involves the use of phosphorus pentachloride and an olefine for removal of chlorine at least in part by addition to carbon-carbon double bond.
Preferred aspects are lasting protection of reactive substituents by silylation and preparation on industrial scale of generally 7β-amino-3-heterocyclic thiomethyl-3-cephem-4-carboxylic acids starting from suitably 7p-phenylacetamido-3-methyl-3-cephem-4-carboxylic acid 9β-oxide.
以 7p-acylamino-3-methyl-3-cephem-4-carboxylic acid 1β-oxide 衍
生物为起点,制备 7β-amino- 和 7β-acylamino-3-Substituted methyl-3-cephem-4-carboxylic acid 衍
生物的多步一步法工艺、包括一种对一般 7p-acylamino-3-cephem-4-carboxylic acid 1-oxide derivatives optionally substituted in the 7a-position 进行脱氧的新工艺,该工艺可作为单一步骤应用,也可并入多步骤工艺而无需分离中间产物。
脱氧涉及使用
五氯化磷和烯烃,至少部分地通过与碳碳双键加成来去除
氯。
优选的方面是通过
硅烷化对活性取代基进行持久保护,并以适当的 7p- 苯乙酰
氨基-3-甲基-3-头孢-4-
羧酸 9β-氧化物为起点,在工业规模上制备一般的 7β-
氨基-3-杂环
硫甲基-3-头孢-4-
羧酸。