发布求助
文献互助 智能选刊 最新文献

Enantiomer最新文献

筛选
英文 中文
Straightforward synthesis of two pairs of enantiomeric butenolides 3-tetradecyl- and 3-hexadecyl-5-methyl-2(5H)-furanone. 两对对映丁烯内酯3-十四烷基和3-十六烷基-5-甲基-2(5H)-呋喃酮的直接合成。
Enantiomer Pub Date : 2002-03-01 DOI: 10.1080/10242430212189
Bu-bing Zeng, T. Hu, W. Yun, Yikang Wu, Yu‐lin Wu
{"title":"Straightforward synthesis of two pairs of enantiomeric butenolides 3-tetradecyl- and 3-hexadecyl-5-methyl-2(5H)-furanone.","authors":"Bu-bing Zeng, T. Hu, W. Yun, Yikang Wu, Yu‐lin Wu","doi":"10.1080/10242430212189","DOIUrl":"https://doi.org/10.1080/10242430212189","url":null,"abstract":"Based on the synthetic method of optically active 3-alkyl-5-methyl-2(5H)-furanones from lactic acid, two pairs of chiral butenolides 3-tetradecyl- and 3-hexadecyl-5-methyl-2(5H)-furanone have been straightforwardly synthesized from methyl stearate and methyl palmitate respectively by aldol condensation with (R)- or (S)-O-tetrahydropyranyl lactal prepared from corresponding ethyl lactate and beta-elimination.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86320530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Structure-chiroptical properties relationship in oxabicyclic beta-lactam derivatives. 氧环-内酰胺衍生物的结构-热带性质关系。
Enantiomer Pub Date : 2002-03-01 DOI: 10.1080/10242430212200
J. Frelek, R. Lysek, K. Borsuk, J. Jagodziński, B. Furman, A. Klimek, M. Chmielewski
{"title":"Structure-chiroptical properties relationship in oxabicyclic beta-lactam derivatives.","authors":"J. Frelek, R. Lysek, K. Borsuk, J. Jagodziński, B. Furman, A. Klimek, M. Chmielewski","doi":"10.1080/10242430212200","DOIUrl":"https://doi.org/10.1080/10242430212200","url":null,"abstract":"The relationship between molecular structure of 5-dethia-5-oxacephams and clavams and their chiroptical properties was investigated by means of X-ray diffraction analysis, molecular modeling calculations and circular dichroism spectroscopy. It was found that the amide chromophore of the beta-lactam unit in these compounds is nonplanar with nitrogen atom having a pyramidal configuration. It was also found that the helicity of the lactam moiety in investigated oxacephams and clavams is controlled by the absolute configuration at the C-6 and C-5 carbon atom, respectively. Thus, the applicability of helicity rule correlating a positive (negative) torsional angle of the beta-lactam subunit O=C-N-C with a negative (positive) sign of the n-->pi* CE, previously applied to oxacephams, is now extended to clavams.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82389264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 15
Evaluation of the origins of the selectivity of polymers imprinted with a HIV protease inhibitor using infrared spectroscopy and high performance liquid chromatography. 利用红外光谱和高效液相色谱法评价HIV蛋白酶抑制剂印迹聚合物选择性的来源。
Enantiomer Pub Date : 2002-03-01 DOI: 10.1080/10242430212193
T. O'brien, N. Grinberg, G. Bicker, J. Wyvratt, N. Snow
{"title":"Evaluation of the origins of the selectivity of polymers imprinted with a HIV protease inhibitor using infrared spectroscopy and high performance liquid chromatography.","authors":"T. O'brien, N. Grinberg, G. Bicker, J. Wyvratt, N. Snow","doi":"10.1080/10242430212193","DOIUrl":"https://doi.org/10.1080/10242430212193","url":null,"abstract":"This work investigates the origins of enantioselectivity of polymers imprinted with the HIV protease inhibitor, Indinavir. For the preparation of imprints of the drug, the critical interactions between the functional monomer, methacrylic acid, and Indinavir were characterized by infrared (IR) spectroscopy to explore the optimum functional monomer concentration for the polymerization. It was shown that a polymer with high selectivity and minimum non-selective binding for Indinavir was obtained when prepared with enough functional monomer to hydrogen bond with all of the functional groups of the drug without using an excess of monomer. This observation is explained in terms of a balance that is achieved in the monomer-template equilibrium during the polymerization that yields a polymer with highly selective sites and minimal non-selective sites. This paper further demonstrates that IR spectroscopy can be a valuable tool in the design and syntheses of molecular imprinted polymers.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81762730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
The supramolecular structure of self-assembly formed by capsanthin derivatives. 辣椒素衍生物自组装形成的超分子结构。
Enantiomer Pub Date : 2002-03-01 DOI: 10.1080/10242430212194
Z. Bikádi, F. Zsila, J. Deli, G. Mády, M. Simonyi
{"title":"The supramolecular structure of self-assembly formed by capsanthin derivatives.","authors":"Z. Bikádi, F. Zsila, J. Deli, G. Mády, M. Simonyi","doi":"10.1080/10242430212194","DOIUrl":"https://doi.org/10.1080/10242430212194","url":null,"abstract":"Carotenoids form structured self-assembly upon aqueous dilution of their organic solutions. In order to test the proposal predicting carotenoid aggregates to be organized in closely packed H-type (card-pack) manner by intermolecular hydrogen bonds, the trihydroxy derivative of capsanthin (1), (6'R)-capsanthol (2) ((all-E,3R,3'S,5'R,6'R)-beta,kappa-carotene-3,3',6'-triol) was acetylated to obtain all varieties of mono-, di- and triacetates and the corresponding supramolecules were studied by UV/Vis- and CD spectroscopy. It was verified that derivatives lacking hydroxyl functions at either of the end-groups form the loosely organized J-type (head-to-tail) aggregates. A model for the structure of the J-type self-assembly is proposed. Evidence was also obtained suggesting that close contacts of carotenoid molecules are not confined to hydrogen bonding.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90979447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 25
Synthesis and characterization of new chiral calix[4]arenes. 新型手性杯[4]芳烃的合成与表征。
Enantiomer Pub Date : 2002-03-01 DOI: 10.1080/10242430212191
Y. Okada, M. Mizutani, Fuyuhiko Ishii, J. Nishimura*
{"title":"Synthesis and characterization of new chiral calix[4]arenes.","authors":"Y. Okada, M. Mizutani, Fuyuhiko Ishii, J. Nishimura*","doi":"10.1080/10242430212191","DOIUrl":"https://doi.org/10.1080/10242430212191","url":null,"abstract":"The unique chiral calixarenes were successfully synthesized by the following two methods: the Williamson ether synthesis and a stepwise ether cleavage with a mild Lewis acid. The high regioselectivity is recognized by the latter stepwise method. The ionophores having oligoethylene glycol unit efficiently extracted larger alkali metal ions like K+, Rb+, and Cs+ than smaller ones like Li+ and Na+. Their ion selectivity apparently changed by the chain length of crown ether. All racemates obtained could be resolved to each enantiomer by HPLC using a chiral column. The calixarenes with planar chirality recognized the chirality of guest molecules. Thus, the (-)-receptor resolved strongly forms 1:1 complex with (R)-(+)-alpha-phenylethylammonium picrate.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91124256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 7
Determination of the absolute configuration of rubroflavin by comparison of measured and calculated CD spectra of its thermolysis product 3-methanesulfinyl-5-methylmercaptophenol. 通过对红黄素裂解产物3-甲磺酸基-5-甲基巯基苯酚CD谱的比较测定红黄素的绝对构型。
Enantiomer Pub Date : 2002-03-01 DOI: 10.1080/10242430212197
G. Raabe, Charlotte Repges, Yuekui Wang, J. Fleischhauer
{"title":"Determination of the absolute configuration of rubroflavin by comparison of measured and calculated CD spectra of its thermolysis product 3-methanesulfinyl-5-methylmercaptophenol.","authors":"G. Raabe, Charlotte Repges, Yuekui Wang, J. Fleischhauer","doi":"10.1080/10242430212197","DOIUrl":"https://doi.org/10.1080/10242430212197","url":null,"abstract":"The absolute configuration of rubroflavin has been determined indirectly by comparison of the measured and the calculated CD spectrum of its thermal decomposition product 3-methanesulfinyl-5-methylmercaptophenol. Performing geometry optimizations at the HF/6-31+G* level we found fifteen local minima for the (R)-isomer of 3-methanesulfinyl-5-methylmercaptophenol. The CD spectrum of the compound was then obtained as a superposition of the Boltzmann-weighted spectra for each structure calculated with the non-empirical CIS method. The corresponding Boltzmann factors have been calculated employing the relative energies of these minima determined at the ZPE + MP2/6-31+G*//HF/6-31+G* level of ab initio theory. Comparing the signs of the observed and calculated longest wave length Cotton effect we assign an absolute configuration to the thermolysis product. Since additional calculations revealed that the tricoordinate sulfur atom in rubroflavin and in its decomposition product is configurationally stable under the conditions of thermolysis we conclude that the absolute configuation at the corresponding sulfur atom of rubroflavin is the same.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91078526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Synthesis of calix[4]arene and porphyrin tethering four chiral five-membered cyclic carbonates. 杯[4]芳烃和卟啉系四手性五元环碳酸盐的合成。
Enantiomer Pub Date : 2002-03-01 DOI: 10.1080/10242430212195
T. Takata, H. Takagi, Yoshio Furusho
{"title":"Synthesis of calix[4]arene and porphyrin tethering four chiral five-membered cyclic carbonates.","authors":"T. Takata, H. Takagi, Yoshio Furusho","doi":"10.1080/10242430212195","DOIUrl":"https://doi.org/10.1080/10242430212195","url":null,"abstract":"Calix[4]arene tethering four chiral five-membered cyclic carbonates 1c was synthesized by O-glycidylation of p-tert-butylcalix[4]arene 1a with (R)-glycidyl tosylate, followed by carbonation with carbon dioxide catalyzed by lithium bromide. Porphyrin tethering chiral five-membered cyclic carbonates 2c was similarly synthesized.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82363106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Strategic placement of stereogenic centers in molecular materials for second harmonic generation. 二次谐波生成分子材料中立体中心的战略性放置。
Enantiomer Pub Date : 2002-03-01 DOI: 10.1080/10242430212190
P. Gangopadhyay, D. Rao, I. Agranat, T. Radhakrishnan
{"title":"Strategic placement of stereogenic centers in molecular materials for second harmonic generation.","authors":"P. Gangopadhyay, D. Rao, I. Agranat, T. Radhakrishnan","doi":"10.1080/10242430212190","DOIUrl":"https://doi.org/10.1080/10242430212190","url":null,"abstract":"Basic aspects of the nonlinear optical phenomenon of second harmonic generation (SHG) and the assembly of molecular materials for SHG are reviewed. Extensive use of chirality as a convenient tool to generate noncentrosymmetricity in molecular lattices, an essential requirement for the development of quadratic nonlinear optical materials, is noted. An overview of our investigations of chiral diaminodicyanoquinodimethanes is presented, which provides insight into a systematic approach to the effective deployment of chirality to achieve optimal molecular orientations for enhanced solid state SHG. Extension of these ideas to the realization of strong SHG in materials based on helical superstructures is outlined.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79660983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
CD of single-stranded, double-stranded, and G-quartet nucleic acids in complexes with a single-stranded DNA-binding protein. 单链、双链和g -四重奏核酸与单链dna结合蛋白复合物的CD。
Enantiomer Pub Date : 2002-03-01 DOI: 10.1080/10242430212192
D. Gray, C. Gray, T. Mou, J. Wen
{"title":"CD of single-stranded, double-stranded, and G-quartet nucleic acids in complexes with a single-stranded DNA-binding protein.","authors":"D. Gray, C. Gray, T. Mou, J. Wen","doi":"10.1080/10242430212192","DOIUrl":"https://doi.org/10.1080/10242430212192","url":null,"abstract":"We review CD studies of a single-stranded DNA binding protein, g5p, of the Ff group of bacterial viruses. The CD spectrum of the g5p is dominated by a positive tyrosine La band at 229 nm, to which all five of the protein tyrosines contribute. The La band becomes much less positive upon binding of g5p to nucleic acids. CD spectra of mutant proteins identified a single tyrosine, Y34, that is largely responsible for this CD perturbation. At >250 nm, CD perturbations of nucleic acids can be monitored during g5p binding, and CD titrations have identified two distinct modes of binding of the g5p at physiological ionic strength (0.2 M NaCl). SELEX selection of sequences bound preferentially by g5p yielded a G-rich sequence that is closely related to telomere sequences and has CD properties of a G-tetraplex. CD spectroscopy showed that the presumed G-quadruplex form is maintained within saturated g5p x DNA complexes.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88563991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 16
Quantitative analysis of incomplete HPLC resolution of enantiomers. Fit of polarimetric detection for D- and L-phenylalanine to a gaussian function. 对映体不完全高效液相色谱的定量分析。D-苯丙氨酸和l -苯丙氨酸的偏振检测符合高斯函数。
Enantiomer Pub Date : 2002-01-01 DOI: 10.1080/10242430210703
T. J. Edkins, P. C. Meier, R. Shah, D. R. Bobbitt, H. Saranadasa, Romeo D Lodevico
{"title":"Quantitative analysis of incomplete HPLC resolution of enantiomers. Fit of polarimetric detection for D- and L-phenylalanine to a gaussian function.","authors":"T. J. Edkins, P. C. Meier, R. Shah, D. R. Bobbitt, H. Saranadasa, Romeo D Lodevico","doi":"10.1080/10242430210703","DOIUrl":"https://doi.org/10.1080/10242430210703","url":null,"abstract":"This report compares laser-based polarimetric and UV data for quantitating incompletely resolved enantiomers by HPLC. Using L- and D-phenylalanine as a working model, response data is shown across the entire detection region while emphasizing the regions at or near 100% L, 100% D and 50:50 L:D at resolutions between 0.4 and 1.4. In general, the poorer the resolution, the greater the improvement in detectability with the polarimeter when compared to UV detection. This is due to the inherent bipolar nature of the polarimetric signal, which creates a well-defined crossing point for integration of an enantiomeric pair. In our previous work, we described the improvement in measurement precision when applying a bipolar gaussian peak model to the raw chromatographic peak data. This study will measure the model's effect on improving accuracy. This study should be applicable to other chiroptical detection strategies that produce a bipolar signal for enantiomers, such as circular dichroism and circularly polarized luminescence.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79602067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
首页 上一页 下一页 尾页
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整，为了账户安全，请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们：info@booksci.cn Book学术提供免费学术资源搜索服务，方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号：481959085
Book学术官方微信