Hypervalent iodine mediated solid state synthesis of 2-aryl-5- [2-(3,4,5-trimethoxyphenyl)[1,8]naphthyridin- 3-yl]-1,3,4-oxadiazoles

Abstract

The hydrazones 5 on oxidative cyclization of with  [PhI(OAc)₂] in the solid state at room temperature under grinding conditions has furnished  the respective  2-aryl-5-[2-(3,4,5-trimethoxyphenyl)[1,8]naphthyridin-3-yl]-1,3,4-oxadiazoles 6 in good yields without any undesirable byproducts. The purity of the products is high. The method is preoperatively convenient, useful and environmentally benign. The experimental procedure is very simple and avoids sophistication. The most probable mechanism of above transformation is suggested. The structure of compounds 5 and 6 has been confirmed by their spectroscopic(IR, ¹H NMR and MS) and analytical data.