Synthesis of [8-14C]-2,6-dichloro-9H-purine, a radiolabelled precursor for 14C-nucleosides

Article abstract of DOI:10.1002/jlcr.2580360509

The synthesis of [8-¹⁴C]-2,6-dichloro-9H-purine (2), a radiolabelled precursor for preparing ¹⁴C-labelled nucleosides, is described. Triethyl [¹⁴]orthoformate was reacted with 4,5-diamino-2,6-dichloropyrimidine (1) in acetonitrile at 90°C with methanesulfonic acid as catalyst to generate 2 in 84% radiochemical yield. Reaction of a with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranos produced [8-¹⁴C]-9-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)-2,6- dichloropurine (3) in 86% yield. The radiochemical purity of 3 was higher than 98% with a specific activity of 36 mCi/mmol. This method has general application to ¹⁴C-labelling of purines in drug development.