Studies On Methodologies For The Synthesis Of 2,5-substituted Oxazole Derivatives

The oxazole r ing has attracted remarkable attention not only because they serve as one of the key building blocks in various natural products, but also due to their synthetic intermediates. A wide variety of synthetic routes have been developed for oxazole derivatives, but there are still some drawbacks. In order to solve these problems, we try to develop a I2/PABS-prompted process for the synthesis of 2,5-substituted oxazoles from ?-amino acids and methyl ketones. The outline of every part as follows:Chapter one: The studies of the oxazole derivatives applicationsOxazole ring structures are widely found in nature, most of oxazole compounds are initially isolated from natural products. Oxazoles represent an important class of five-membered N-heterocyclic aromatic compounds, they have numerous significant applications, for example: Antiviral properties, anticancer properties, antibacterial and antifungal properties, antiHCV?antileukemia?antidiabetes and other diseases, for the unique characteristics of fluorescent labeled biological molecules, etc.Chapter two: The studies of the oxazole derivatives synthesisTo date, a wide variety of synthetic routes have been developed for oxazole derivatives, according to the different starting materials, we divided into six categories:(1) amide;(2) amine;(3) amino acids;(4) carboxylic acid;(5) ketones;(6) nitriles.Chapter three: Methodologies for the Synthesis of 2,5-substituted oxazole derivativesWe develop a new process for the synthesis of polysubstituted oxazoles from ketones and amino acids using I2/PABS-prompted system. The conversion has many advantages: cheap and readily available starting materials, simple and mild reaction conditions, short reaction time, high yields and most of the products can be obtained more than 80% yield.