SYNTHETIC STUDIES FOR NOVEL STRUCTURE OF ALPHA-NITROGENOUSLY FUNCTIONALIZED ALPHA-FLUOROCARBOXYLIC ACIDS .3. SOME REACTIONS OF ALPHA-BROMO-ALPHA-FLUOROCARBOXYLIC ACIDS AND THEIR ETHYL-ESTERS WITH SODIUM-AZIDE

Synthesis of a novel group of alpha-azido-alpha-fluorocarboxylic acid derivatives has been attempted by azidation of the corresponding alpha-bromo-alpha-fluorocarboxylic acids or ethyl esters. Although ethyl azidofluoroacetate was obtained, over-azidation occurred very readily in most cases to afford geminally diazidated compounds. Attempted conversion of ethyl azidofluoroacetate into azidofluoroacetic acid by alkaline hydrolysis or by treatment with trimethylsilyl bromide resulted mainly in the formation of defluorinated products. It was found that, although alpha-fluorocarboxylates are generally considered stable, defluorination occurs under nucleophilic conditions if an additional labilizing group is present on the same carbon atom as the fluorine.