The synthesis of [1′,3′‐3H]4‐(4′‐azido‐5′,6′,7′,8′‐tetrahydro‐5′,5′,8′,8′‐tetramethyl‐2′‐anthracenyl)benzoic acid as a probe of the retinoic acid receptor

The synthesis of [1′,3′-3H]4-(4′-azido-5′,6′,7′,8′-tetrahydro-5′,5′,8′,8′-tetramethyl -2′-anthracenyl)benzoic acid is described. This retinoid was designed as a photoaffinity probe of the receptor sites of cellular retinoic acid-binding protein and the nuclear retinoic acid receptor protein. The [3H]azidoretinoid was prepared from 1,2,3,4-tetrahydro-1,1,4,4-tetramethyl-7-(4-methylphenyl)-5-nitroanthracene in five steps in 15% yield (89% radiochemical purity by HPLC). 1H and 3H NMR was used to confirm the sites of 3H substitution on the ring.