Efficacious One-pot Synthesis of 2-thiazolines and 2-oxazolines Under Solvent and Metal-Free Conditions

Background: 2-oxazolines and 2-thiazolines are important heterocycles due to their extensive applications in chemistry, biochemistry, and pharmacology. Most of the precedent methods for preparing these heterocycles involve one or more drawbacks, including harsh reaction conditions, long reaction times, low yields of products, high temperature, and toxic solvents. Objective: The aim of this study was to develop a new and eco-efficient method for the preparation of 2-oxazolines and 2-thiazolines. Methods: Amino alcohols were condensed with nitriles in a sealed tube under solvent-free and metal- free conditions. Results: Our procedure appears to be highly eco-efficient and promotes quantitative access to 2-oxazolines and 2-thiazolines using simple and minimum manipulation. Conclusion: This simple approach allows high conversion for different nitriles yielded from 78 to 99% and easy isolation of the targeted products without further purification. To the best of our knowledge, our procedure is the most efficient and fast method reported to date in terms of chemical yields, number of steps, and atom economy.