Photolabile protecting groups for nucleosides: Synthesis and photodeprotection rates
Photolabile protecting groups for nucleosides: Synthesis and photodeprotection rates
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DOI：
10.1016/s0040-4020(97)00154-3
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发表时间：
1997-03-24
期刊：
影响因子：
2.1
通讯作者：
Foote, RS
中科院分区：
文献类型：
--
作者：
Hasan, A;Stengele, KP;Foote, RS
邻硝基苄氧羰基和一些相关的基团已经被测试过对核苷5‘-羟基的耐光性保护。在相同的条件下，在365 nm处照射一系列5‘-O保护的胸腺嘧啶核苷衍生物，光去保护率大约变化了17倍。研究发现，同系物2-(邻硝基苯基)乙氧基及其衍生物的脱除速度大约是相应的邻硝基的2倍，这可能是由于光激发的硝基减少了α-氢的抽提。苯环和α-碳上的取代都会影响光解速率，其中α-位上甲基或第二个邻硝基苯基的存在对光解速率的促进作用最强。在所研究的环取代衍生物中，邻硝基和邻碘对光脱保护的增强作用最强，而邻氟基则降低了光脱保护的速率。总体而言，苯环上其他位置的取代对光解速率的影响较小。(C)1997年爱思唯尔科学有限公司。
o-Nitrobenzyloxycarbonyl and a number of related groups have been tested for the photolabile protection of nucleoside 5'-hydroxyls. The rates of photodeprotection were found to vary by approximately 17 fold in a series of 5'-O-protected thymidine derivatives irradiated at 365 nm under identical conditions. The homologous 2-(o-nitrophenyl)ethoxycarbonyl group and its derivatives were found to be removed approximately 2-fold faster than the corresponding o-nitrobenzyloxycarbonyl group, possibly due to an increased rare of alpha-hydrogen abstraction by the photo-excited nitro group. Photolysis rates were affected by substitutions on both the phenyl ring and alpha-carbon, with the strongest rate enhancements caused by the presence of a methyl or second o-nitrophenyl group in the alpha-position. Among the ring-substituted derivatives studied, o-nitro and o-iodo had the strongest enhancement effects on photodeprotection, while an o-fluoro group reduced the rate of photodeprotection. In general, substitutions at other positions on the phenyl ring had less effect on photolysis rates. (C) 1997 Elsevier Science Ltd.