N-(1-{(1R,3R,4R,7S)-1-{[bis(4-methoxyphenyl)(phenyl)methoxy]methyl}-7-hydroxy-2-oxa-5-azabicyclo[2.2.1]hepta-3-yl}-5-methyl-2-oxo-1,2-dihydropyrimidin-4-yl)benzamide 、
1-Acetyl-2,3-dimethyl-isothiourea 在
silver trifluoromethanesulfonate 、
N,N-二异丙基乙胺 作用下,
以
四氢呋喃 为溶剂,
反应 1.0h,
以83%的产率得到(1R,3R,4R,7S)-5-(N'-acetyl-N-methylcarbamimidoyl)-1-(4,4'-dimethoxytrityl)oxymethyl-3-(O
6-diphenylcarbamoyl-N2-isobutyrylguanine-9-yl)-2-oxa-5-azabicyclo[2.2.1]heptan-7-ol