Environmentally friendly iron-catalyzed cascade synthesis of 1,2,4-benzothiadiazine 1,1-dioxide and quinazolinone derivatives.

We have developed an efficient iron-catalyzed method for the cascade synthesis of 1,2,4-benzothiadiazine 1,1-dioxide and quinazolinone derivatives. The protocol uses inexpensive and environmentally friendly FeCl(3) as the catalyst, and no ligand or additive was required. This is the first example of construction of nitrogen-containing heterocycles via iron-catalyzed N-arylation in the absence of ligand. Therefore, this method is of practical application for the synthesis of the two different nitrogen-containing heterocycles.