Synthesis of 5‐deazaflavin adenine dinucleotide (5‐dFAD) using a modified triester approach

Starting from D‐ribose and 3,4‐xylidine, a fifteen‐step synthesis is described for the preparation of 5‐dFAD (18). The synthesis involves as key intermediates, 5‐deazariboflavin (8), its 2′,3′,4′‐tris‐O‐(tetrahydropyranyl) derivative (12) and 2′,3′,4′‐tris‐O‐(tetrahydropyranyl)‐5′‐O‐(morpholinophosphonyl)‐5‐deazariboflavin (15).