Synthesis of 14C‐labeled flame retardants. 14C‐labeled‐tetrabromophthalic anhydride and tetrabromobisphenol‐A

The multistep syntheses of tetrabromophthalic‐1,2,3,4,5,6‐U‐14C anhydride 6, and 3,5,3′,5′‐tetrabromo‐4,4′‐isopropylidenedi‐(phenol‐U‐14C) 11, are described. The synthesis pathway to 6 includes a novel preparation of phthalic acid‐1,2,3,4,5,6‐U‐14C acid from benzene‐U‐14C. Both 6 and 11 were obtained in 9% overall radiochemical yield (based on benzene‐U‐14C).