US Patent 7371897 Preparation method for (Z)-7-chloro-((S)-2,2-dimethylcyclopropanecarboxamido)-2-heptenoic acid

Provided is a novel preparation method of (Z)-7-chloro-((S)-2,2-dimethylcyclopropanecarboxamido)-2-heptenoic acid represented by the following formula (1), a key intermediate of cilastatin used as a supplement to imipenem. The novel preparation method of the invention produces a pure (Z)-7-chloro-((S)-2,2-dimethylcyclopropanecarboxamido)-2-heptenoic acid, a key intermediate of cilastatin, by selective hydrolysis of E isomers.