We report an improved synthesis of N-6-(6-aminohexyl)FAD (1) using an
efficient one-pot conversion of inosine to the N-trifluoroacetyl prote
cted N-6-(6-aminohexyl)adenosine 3. The 5'-O-phosphorylated AMP deriva
tive 4, activated as the imidazolide, was coupled with commercial sodi
um riboflavin phosphate by using 18-crown-6 in DMF.