4,4′,4″-Tris(levulinoyloxy)trityl as a New Type of Primary Hydroxyl Protecting Group
作者:Mitsuo Sekine、Tsujiaki Hata
DOI:10.1246/bcsj.58.336
日期:1985.1
The 4,4′,4″-tris(levulinoyloxy)trityl (TLTr) group was introduced selectively on the 5′-oxygen of thymidine by use of in situ generated 4,4′,4″-tris(levulinoyloxy)trityl bromide. The TLTr group was found to be sufficiently stable to acids and readily removed by hydrazinolysis followed by warming to 50 °C in pyridine–acetic acid without damage of other protecting groups such as the O-acetyl and 4,4′-dimethoxytrityl
通过使用原位生成的 4,4',4"-三(乙酰丙酰氧基)三苯甲基溴,将 4,4',4"-三(乙酰丙酰氧基)三苯甲基(TLTr)基团选择性地引入胸苷的 5'-氧上。发现 TLTr 基团对酸足够稳定,很容易通过肼解去除,然后在吡啶-乙酸中加热至 50°C,而不会损坏其他保护基团,例如 O-乙酰基和 4,4'-二甲氧基三苯甲基。这种新保护基团的效用通过胸苷基 (3'–5')-胸苷的成功合成得到证明,其中 TLTr 基团用作 5'-羟基保护基团。