Synthesis of double-13C-labeled imidazole derivatives

Abstract Double- 13 C-labeled imidazole-4-carboxamide (ICA: 13 C 2 - 1 ) and 5-aminoimidazole-4-carboxamide-1-β-riboside (AICAr: 13 C 2 - 5 ) were synthesized from stable isotope-labeled sodium cyanide and triethyl orthoformate. The key intermediate, 4-aminoimidazole-5-carboxamide (AICA: 13 C 2 - 4 ), should also provide access to double- 13 C-labeled histidine and adenosine derivatives via reported methods.