Synthesis of Fluorinated Proline Analogs for the Potential Inhibition of Proline Oxidase

Proline oxidase is an enzyme that has been isolated from the inner membrane of rat liver mitochondria. It is the catalyst in the first step of the metabolic pathway for proline-glutamate interconversion. The enzyme is specific for L-proline which is oxidized to Æ-pyrroline- 5-carboxylic acid. 4,4- difluoro-L-proline has demonstrated irreversible inhibition of proline oxidase. Further kinetic studies of this inhibition need to be performed in order to elucidate a mechanism for the inhibition. Information regarding the site of the oxidation of proline may also be obtained from these studies. New synthetic routes to 4,4-difluoro-L-proline, and the cis and trans non- fluorinated isomers have been attempted which utilize new blocking groups and fluorinating reagents in the hopes of making these compounds more accessible