A Novel Method for the Synthesis of Dinucleoside Boranophosphates by a Boranophosphotriester Method
摘要:
2'-Deoxyribonucleoside-3'-boranophosphates (nucleotide monomers), including four kinds of nucleobases, were synthesized in good yields by the use of new boranophosphorylating reagents. We have explored various kinds of condensing reagents as well as nucleophilic catalysts for the boranophosphorylation reaction with nucleosides. In the synthesis of dinucleoside boranophosphates, undesirable side reactions occurred at the O-4 of thymine and the O-6 of N-2-phenylacetylguanine bases. To avoid these side reactions, additional protecting groups, benzoyl (Bz) and diphenylcarbamoyl (Dpc) groups, were introduced to thymine and guanine bases, respectively. As a result, the condensation reactions proceeded smoothly without any side reactions, and the dimers including four kinds of nucleobases were obtained in excellent yields. In the deprotection of the 5'-DMTr group, Et3SiH was found to be effective as a scavenger for the DMTr cation which caused a P-B bond cleavage. After removal of the other protecting groups by the conventional procedure, four kinds of dinucleoside boranophosphates were obtained in good yields.
发现2-(三甲基甲硅烷基)乙基(TSE)基团作为寡核苷酸合成中核苷酸间磷酸的保护基是有效的。具有良好产率的具有TSE基团的亚磷酰胺构件被制备。在脱氧鸟苷的情况下,合成了2- N-未保护的亚磷酰胺结构单元。这些化合物被用于寡脱氧核糖核苷酸的固相合成。通过31 P NMR阐明了与未保护的鸟嘌呤部分相关的副反应。
An investigation of antibody acyl hydrolysis catalysis using a large set of related haptens
作者:Amy L. Odenbaugh、Eric D. Helms、Brent L. Iverson
DOI:10.1016/s0968-0896(99)00302-8
日期:2000.2
observed in the catalytic activities of polyclonal antibodieselicited by the different haptens. A phosphate hapten with a phenyl ring on the side of the hapten opposite the linker elicited reproducibly high levels of polyclonal antibodycatalytic activity. The other 11 haptens, most with benzyl groups on the side of the hapten opposite the linker, elicited immune responses in which catalytic activity was
Synthesis and Kinetic Evaluation of Inhibitors of the Phosphatidylinositol-Specific Phospholipase C from <i>Bacillus cereus</i>
作者:Stephen F. Martin、Allan S. Wagman
DOI:10.1021/jo960850q
日期:1996.11.15
Substrate analogues of phosphatidylinositol (1) were synthesized and evaluated as potential inhibitors of the bacterial phosphatidylinositol-specific phospholipaseC (PI-PLC) from Bacillus cereus. The chiral analogues of the water-soluble phospholipid substrate 5 were designed to probe the effects of varying the inositol C-2 hydroxyl group, which is generally believed to serve as the nucleophile in
GMP Synthetase: Synthesis and Biological Evaluation of a Stable Analog of the Proposed AMP-XMP Reaction Intermediate
作者:Edward J. Salaski、Hans Maag
DOI:10.1055/s-1999-3104
日期:——
The enzyme guanosine monophosphate synthetase is part of the de novo purine synthesis pathway and is responsible for the conversion of xanthosine monophosphate to guanosine monophosphate. The phosphate-linked adenyl-XMP 1 has been proposed as the intermediate in a stepwise mechanism for this conversion. Direct observation of 1; either as produced in the enzymatic reaction, or as a potential synthetic target is not readily feasible due to the high lability of the phosphate linkage. We therefore undertook the synthesis of the phosphonate 2 as a stable analog of this proposed intermediate. The successful synthetic strategy involved the coupling under Mitsunobu conditions of a 2-phosphorylmethyl inosine with an adenosine derivative. This gave 2 after deprotection and 5′ monophosphate formation of the initial coupling product. Compound 2 inhibited GMP synthetase with a Ki of 0.56 μM.
Use of 2-trimethylsilylethyl as a protecting group in phosphate monoester synthesis
作者:Akiyoshi Sawabe、Sandra A. Filla、Satoru Masamune
DOI:10.1016/0040-4039(93)88016-c
日期:1992.12
demonstrated that phosphorylation of a highly hindered hydroxyl group can be achieved via sequential treatment with (1) 2-trimethylsilylethyl dichlorophosphite, (2) 2-trimethylsilylethyl alcohol, and (3) hydrogen peroxide. The resulting triester survives a variety of reaction conditions but may be cleaved with fluoride ion to afford the phosphate monoester.
carried out a comprehensive study that analyzes the evolution of catalyticactivity in the polyclonalantibodieselicited by a phosphate hapten over the course of an immunization regimen. We have found that catalyticactivityelicited by the phosphate hapten 1, measured as apparent kcat for the hapten-specific fraction of polyclonalantibodies, increased through the first four or five immunizations, then