Organic Phosphates. XX. Syntheses of 1-(3-Cyanoethylphosphoryl-5-trityl-D-ribofuranosyl)-2(1H)-pyrimidinone, -6(1H)-pyrimidinone, and -2(1H)-pyridone and their Properties as Substrate of Bovine Pancreatic Ribonuclease

Abstract

On condensation of chloromercuri-salt of 2-pyridinol and 2, 3, 5-tri-O-benzoylribofuranosyl chloride, 2-O-(2, 3, 5-tri-O-benzoylribofuranosyl)-pyridine (VII) was obtained, the ribosyl group of which migrated to furnish N₁-(2, 3, 5-tri-O-benzoylribofuranosyl)-2-(1H)-pyridone (VIII) on treatment with mercuric bromide. 1-β-D-Ribofuranosyl-2(1H)-pyridone (III) obtained from VIII by alkaline hydrolysis and two other nucleosides, 1-β-D-ribofuranosyl-2(1H)-pyrimidinone (I) and -6(1H)-pyrimidinone (II) were converted to respective 5'-trityl-3'-cyanoethylphosphates, (Ic), (IIc) and (IIIc), and the property of these nucleotides as substrates of bovine pancreatic ribonuclease was investigated. The result was that Ic revealed about three fourth activity as substrate of the enzyme compared with 5'-trityl-3'-cyanoethylphosphate of uridine (IVc), but IIc and IIIc were much less active than Ic. The relation between structure of base group of these nucleotides and their properties as substrate of RNase-A was discussed.