Synthesis of 5-isoxazol-3-yl-pyrimidine nucleosides as potential antileishmanial agents

Abstract

A simple and practical procedure for the preparation of C5-(isoxazol-3-yl)-pyrimidine nucleosides through 1,3-dipolar cycloaddition of the in situ formed C5-nitrile oxide substituted pyrimidine nucleosides with various terminal alkynes is presented. Compared with literature procedures, this new method has advantageous features such as readily available and inexpensive starting materials, simple procedure without using expensive transition metal catalyst, and broad scope of substrates. By employing this method, 30 nucleoside analogues were prepared in moderate yields. Biological studies on these C5-(isoxazol-3-yl)-pyrimidine nucleosides showed that most of them exhibited significant in vitro antileishmanial activity.

Keywords: 1,3-Dipolar cycloaddition; Antileishmanial activity; Hybrid; Isoxazole; Pyrimidine nucleoside.