Regiospecific synthesis of polychlorinated dibenzofurans with chlorine‐37 excess

The synthesis of regiospecifically chlorine‐37 labeled di‐ and trichlorodibenzofurans is described. The strategy for introducing a chlorine‐37 label regiospecifically has been to reduce the nitro derivative to the corresponding amine. The amine is converted to the diazonium salt with t‐butyl nitrite, and this product is converted to the final product via the Sandmeyer reaction with chlorine‐37 labeled cuprous chloride.