Synthesis of [3 H] and [14 C]genipin

Abstract

[³ H]Genipin was synthesized in a single step by Ir(I) catalyzed hydrogen isotope exchange. Conditions for selective exchange of the sp² CH bond ortho to the methyl ester functionality were developed through deuterium modeling studies through a catalyst screen. Optimized conditions so obtained were then utilized with tritium gas to generate [³ H]genipin at a specific activity of 18.5 Ci/mmol. Racemic [¹⁴ C]genipin was prepared in eight steps in overall 5.4% radiochemical yield from potassium [¹⁴ C]cyanide.

Keywords: Gardenia Blue; Iridium (I); Otera's catalyst; carbon-14; genipin; tritium.