The research work carried out in this book aims to develop a simple and rapid synthesis route for new chiral derivatives of 1,2,4-oxadiazin-5-ones known for their interesting biological activities.The first part of this book describes the synthesis of a series of optically active -bromoacids by enantioselective nitrous deamination of natural amino acids. These will subsequently react with thionyl chloride followed by methanol to give the corresponding -bromoesters.Condensation of these previously prepared -bromoesters with 1-benzenesulfonylpyrrolidin-2-carboxamidoxime in the presence of two equivalents of sodium hydride offers desired new chiral 1,2,4-oxadiazin-5-ones in good chemical yields.