TsNBr 2 Mediated Synthesis of 2‐Acylbenzothiazoles and Quinoxalines from Aryl Methyl Ketones under Metal Free Condition

An efficient one pot strategy has been developed for the synthesis of 2‐acylbenzothiazoles and quinoxalines from aryl methyl ketones. A variety of heterocycles of these two categories could be prepared in a two‐step sequence in excellent yields. The reaction was performed starting from aromatic ketones via an aryl gloxal intermediate which, on further condensation with 2‐aminobenzenethiol or o ‐phenylenediamine, produces the corresponding heterocyclic skeleton. Aromatic ketones are initially treated with TsNBr 2 in DMSO at 65 °C for 3 h and the crude reaction mixture was treated with 2‐aminobenzenethiol (at 80 °C) or o ‐phenylenediamine (at RT) to generate the final compound.