A simple, cost-effective method for the regioselective deuteration of anilines

A highly effective and operationally simple method for the regioselective deuteration of anilines is presented. A variety of electron-rich and electron-deficient anilines are efficiently deuterated at the ortho and/or para position with respect to the nitrogen in the presence of 1 equiv of conc HCl in D(2)O. Under the present conditions, aromatic methoxy groups do not facilitate deuteration, enabling a chemo- and regioselective deuteration of p-anisidine.