This reaction may be conducted in a solvent which does not affect the reaction such as an aromatic hydrocarbon such as benzene, toluene, or xylene; an alcohol such as methanol or ethanol; an ether such as tetrahydrofuran, dioxane, or monoglyme; a halogenated hydrocarbon such as methylene chloride, chloroform, or carbon tetrachloride; a nonprotonic polar solvent such as dimethylformamide, dimethyls