This first-of-its-kind four-volume book series provides up-to-date information on α-amino acids, detailing the potential challenges in working with α-amino acids, the protecting groups for the carboxyl, side chain groups of the amino acids, and the most popular heterocyclic compounds that are originating from α-amino acids. These heterocyclic compounds include hydantoins, thiohydantoins (including 2-thiohydantoins, 4-thiohydantoins, 2,4-dithiohydantoins), 2,5-diketopiperazines, N-carboxyanhydrides, N-thiocarboxyanhydrides, sydnones, sydnonimines, azlactones, pseudoazlactones, and oxazolidin-5-ones. This is the first resource to comprehensively present all the heterocycles that can be directly prepared from α-amino acids. In addition, almost all kinds of synthetic methods for a particular type of heterocycles from α-amino acids are included, along with the detailed mechanistic discussions and experimental procedures.Volume 4: Azlactones and Oxazolidin-5-onesdiscusses two types of simple heterocycles that can be prepared from α-amino acids, i.e., azlactones (also known as oxazolones, 4-unsaturated azlactones included) and oxazolidin-5-ones. These heterocyclic compounds behave differently in both biological and chemical properties, and their biological activities are presented in a well-organized manner in this volume.The other volumes in the set are:Volume 1: Protecting GroupsVolume 2: Hydantoins, Thiohydantoins, and 2,5-DiketopiperazinesVolume 3: N-Carboxyanhydrides, N-Thiocarboxyanhydrides, and SydnonesAll together, this unique 4-volume set thoroughly covers the two types of heterocyclic compounds that are originated from alpha-amino acids, providing carefully compiled updated information with detailed examples. The author has shared many thoughtful insights based on his strong background in physical organic chemistry. The volumes will be highly valuable for graduate students and senior students, as well as for professors and researchers working in the field of medicinal and pharmaceutical chemistry, organic chemistry, organic synthesis, heterocycles, and proteins and peptides.