A regioselective synthesis of multi-substituted 2-imino-1,3-oxazolines by one-pot reaction

Abstract

Heterocycles are significant chemical entities for research on small molecule drugs and their development in the pharmaceutical industry. Attention until now has focused on synthetic methods for forming heterocycles. However, new and efficient synthetic methods for the construction of heterocyclic molecules are now being researched continuously. In our previous papers, we reported the construction of two different combinatorial libraries, including novel 2- imino-1,3-thiazolines 1, that show T-type calcium channel inhibitory activity1 and fungicidal property.2 Recently, a number of reports examined the significant biological activities of the 2-imino-1,3-thiazoline derivatives.3 As an extension of our efforts to investigate the biological activities of their analogues, we synthesized 2-imino-1,3-oxazolines 2, which are isosteres of 2-imino-1,3-thiazolines 1 (Figure 1). In the present study we investigate a method for synthesizing multi-substituted 2-imino-1,3-oxazolines 2 with the aim of increasing the diversity in chemical structures. A comparison of the biological activity of 1 and 2 promises to increase our understanding of the structure-activity relationship of this series.