Enantiomer最新文献

Drug Racemization and Its Significance in Pharmaceutical Research 药物外消旋化及其在药学研究中的意义

Enantiomer Pub Date : 2003-01-01 DOI: 10.1007/978-3-642-55842-9_4

M. Reist, B. Testa, P. Carrupt

引用次数: 12

Asymmetric alpha-alkylation of phenylacetates using 2-alkylamino-2'-hydroxy-1,1'-binaphthyls as chiral auxiliaries. 以2-烷基氨基-2'-羟基-1,1'-联萘为手性助剂的苯乙酸酯的不对称烷基化反应。

Enantiomer Pub Date : 2002-11-01 DOI: 10.1080/10242430215713

Masato Kawamura, Takashi Kurahashi, Shinsaku Shiraishi, Kazuaki Kudo

引用次数: 0

Asymmetric cyclopropanation catalyzed by a series of copper-(Schiff-base) complexes with two chiral centers. 具有两个手性中心的铜-(希夫碱)配合物催化的不对称环丙烷化反应。

Enantiomer Pub Date : 2002-11-01 DOI: 10.1080/10242430215705

Changsheng Jiang, Zhang Ming, Qitao Tan, Dai Qian, Tianpa You

引用次数: 11

Cobalt complex of cinchonine: intermolecular interactions in two crystalline modifications. 金鸡宁钴配合物:两种晶体修饰中的分子间相互作用。

Enantiomer Pub Date : 2002-11-01 DOI: 10.1080/10242430215706

Agnieszka Skórska, Barbara J Oleksyn, Jan Sliwiński

引用次数: 5

Chiroptical properties of acridino-18-crown-6 ligands and their complexes with chiral and achiral protonated primary (aralkyl) amine guest molecules. 吖啶酮-18-冠-6配体及其与手性和非手性质子化伯胺客体分子配合物的手性。

Enantiomer Pub Date : 2002-11-01 DOI: 10.1080/10242430215699

Szilvia Szarvas, Zsuzsa Majer, Péter Huszthy, Borbála Vermes, Miklós Hollósi

{"title":"Chiroptical properties of acridino-18-crown-6 ligands and their complexes with chiral and achiral protonated primary (aralkyl) amine guest molecules.","authors":"Szilvia Szarvas, Zsuzsa Majer, Péter Huszthy, Borbála Vermes, Miklós Hollósi","doi":"10.1080/10242430215699","DOIUrl":"https://doi.org/10.1080/10242430215699","url":null,"abstract":"This paper reports CD spectroscopic studies on acridino-18-crown-6 ligands (RR)-2 and 2a (see Figure 1), and their complexes with the enantiomers of alpha-naphthyl)ethylamine hydrogenperchlorate (1-NEA), 1-phenylethylamine hydrogenperchlorate (PEA) and alpha-2-naphthyl)ethylamine hydrogenperchlorate (2-NEA), and also with the achiral guests (1-naphthyl)methylamine hydrogenperchlorate (1-NMA), benzylamine hydrogenperchlorate (BA), methylamine hydrogenperchlorate (MA) and 1-methylnaphthalene (1-MN). The general feature of the CD spectra of complexes of (RR)-2 with MA, BA, (R)- and (S)-PEA is the replacement of the oppositely signed 1Bb doublet of the host by one positive band near 265 nm. The CD spectra of the heterochiral and homochiral complexes of phenazino and acridino hosts (R,R)-1, 1a, (R,R)-2 and 2a with (R)- and (S)-1-NEA and 1-NMA are governed by exciton interaction. Surprisingly, the heterochial [(R,R)/(S)] complexes of the structural isomeric 2-NEA gave rise to a positive couplet in contrast to the negative couplet measured in the spectrum of the heterochiral [(R,R)/(S)] complexes of 1-NEA.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":"7 6","pages":"241-9"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22294649","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: 12

New crystalline complex of quinine and quinidine. 奎宁和奎尼丁的新结晶配合物。

Enantiomer Pub Date : 2002-11-01 DOI: 10.1080/10242430215708

Grazyna Paliwoda, Barbara J Oleksyn, J Sliwiński

{"title":"New crystalline complex of quinine and quinidine.","authors":"Grazyna Paliwoda, Barbara J Oleksyn, J Sliwiński","doi":"10.1080/10242430215708","DOIUrl":"https://doi.org/10.1080/10242430215708","url":null,"abstract":"A new complex of diastereoisomeric pair, quinine and quinidine (QQd), was obtained from a mixture of saturated ethanol solutions of quinine and quinidine (0.5:1). The complex crystallises in the triclinic system, space group P1, and contains two molecules of quinine, two molecules of quinidine and four water molecules in the asymmetric unit. The X-ray structure analysis of a single crystal revealed that quinine and quinidine molecules occur in the so-called open conformation, characteristic for Cinchona alkaloids, whenever they are engaged in intermolecular hydrogen bonds. Quinine and quinidine molecules are organized in two very similar kinds of chains. In each chain the links that contain 14-membered rings can be distinguished. Within these rings quinine and quinidine molecules interact via intermolecular hydrogen bonds between the quinuclidine nitrogens and hydroxyl groups, mediated by water molecules. The links are connected with each other by hydrogen bonds between water molecules and nitrogens of the quinoline moieties, which interact via pi-pi stacking. The architecture of the hydrogen bond system in QQd, compared to those observed in the crystal structures of nonhydrated quinidine, cinchonine and cinchonidine, reveals the effect of the co-crystallizing water on the molecular packing. In nonhydrated alkaloid structures the hydrogen-bonded molecules form helical chains, different from those observed in the hydrated QQd complex and hydrated quinine toluene solvate (QTol). Comparison of QQd structure with that of QTol suggests that while the intermolecular hydrogen bonds in the system quinine-water-quinidine-water are very similar to those in quinine-water-quinine-water system, the mode of pi-pi interaction between their quinoline moieties depends on the absolute configuration of the interacting alkaloid molecules.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":"7 6","pages":"387-96"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22295109","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

Conformational analysis and TDDFT calculations of the chiroptical properties of tris [1,2-propanediolato(2-)-kappaO,kappaO'] selenium/tellurium and related compounds. 三[1,2-丙二醇(2-)-kappaO,kappaO']硒/碲及其相关化合物的构象分析和TDDFT计算。

Enantiomer Pub Date : 2002-11-01 DOI: 10.1080/10242430215700

Yuekui Wang, Jörg Fleischhauer, Stephan Bausch, Milan Sebestian, Peter H Laur

{"title":"Conformational analysis and TDDFT calculations of the chiroptical properties of tris [1,2-propanediolato(2-)-kappaO,kappaO'] selenium/tellurium and related compounds.","authors":"Yuekui Wang, Jörg Fleischhauer, Stephan Bausch, Milan Sebestian, Peter H Laur","doi":"10.1080/10242430215700","DOIUrl":"https://doi.org/10.1080/10242430215700","url":null,"abstract":"The tris(didentate) chelates [E(OCR1R2CR3R4O)3], with E = Se and Te, display both configurational (delta or lambda; R or S) and conformational (delta or lambda) chirality. In order to assess the contributions of these three chiral arrays to the Cotton effects of the chelates and to elucidate their stereochemistry in the gas phase and in solution, calculations of the UV and CD spectra (down to 180 nm), and also of the relative stability of the chelates, have been performed at the TDDFT/TZVP/B-P86 level. An extensive conformational analysis has supplied additional information on the relevant conformers in the conformational manifold. It was found that the dominant CD effect reflects mostly the delta/lambda twists of the three five-membered ligand rings, and less so the influence of the A/A core configuration, while the contributions of any R/S chiral carbon atoms of the ligand rings are negligible. The sign, the intensity, and the energy of this dominant CD band are found to depend on the stereochemistry of the chelates in a predictable way. Among the conformers, those with equatorially disposed methyl substituents are much preferred. These results make it possible to determine the absolute configuration (A/A) and conformation (delta/lambda) of the chelates from the CD data.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":"7 6","pages":"343-74"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22295710","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

Mixed cobalt(III) complexes with aromatic amino acids and diamine. Part IV. Influence of noncovalent intra-and interligand interactions on rotamer population of the S-phenylalaninato and S-tyrosinato side groups in (1,2-diaminoethane)bis-(S-aminocarboxylato)cobalt(III) complexes. 混合钴(III)配合物与芳香氨基酸和二胺。第四部分:非共价配体内和配体间相互作用对(1,2-二氨基乙烷)双-(s-氨基羧基)钴(III)配合物中s-苯丙氨酸和s-酪氨酸侧基的旋转体居群的影响。

Enantiomer Pub Date : 2002-11-01 DOI: 10.1080/10242430215714

Dj U Miodragović, S M Milosavljević, M J Malinar, M B Celap, N Todorović, N Juranić

引用次数: 4

Stereochemistry of (E)- and (Z)-1,1'-dichlorobifluorenylidenes, substituted overcrowded fullerene fragments. 取代过满富勒烯片段的(E)-和(Z)-1,1'-二氯双氟乙烯基的立体化学。

Enantiomer Pub Date : 2002-11-01 DOI: 10.1080/10242430215701

Sergey Pogodin, Shmuel Cohen, P Ulrich Biedermann, Israel Agranat

{"title":"Stereochemistry of (E)- and (Z)-1,1'-dichlorobifluorenylidenes, substituted overcrowded fullerene fragments.","authors":"Sergey Pogodin, Shmuel Cohen, P Ulrich Biedermann, Israel Agranat","doi":"10.1080/10242430215701","DOIUrl":"https://doi.org/10.1080/10242430215701","url":null,"abstract":"X-ray crystallographic and semiempirical PM3 and AM1 studies of 1,1'-dichlorobi-9H-fluoren-9-ylidene (5) are reported. The X-ray molecular structure of (Z)-5 indicated an approximately C2 symmetric conformation with pure twist around C9 = C9' of 40.4 degrees. The fjord regions are somewhat overcrowded: r(C8...C8') = 315.3 pm, r(Cl(1)...Cl(1') = 341.7 pm, r(C(8)...H(8')) = 259.0 pm. The four chlorine atoms of two neighboring molecules of (Z)-5 form a chain. The PM3 calculations showed that the global minimum of 5 is the C2 symmetric twisted conformation t(E)-5, which is 2.4 kJ/mol more stable than its diastereomer C2-t(Z)-5. The corresponding AM1 relative stability is reversed: C2-t(Z)-5 is 1.1 kJ/mol more stable than C2-t(E)-5. The pure twists of t(Z)-5 and t(E)-5 are 37.0 degrees and 37.2 degrees (PM3) and 40.5 degrees and 39.1 degrees (AM1). The corresponding (E) --> (Z) (PM3) and (Z) --> (E) (AM1) energy barriers of diastereomerization are 80.6 kJ/mol (PM3) and 75.8 kJ/mol (AM1). Two anti-folded local minima conformations C2-a(Z)-5 and C(i)-a(E)-5 were found to be 21.2 and 29.5 kJ/mol (PM3) and 25.8 and 35.2 kJ/mol (AM1) less stable than t(E)-5. The syn-folded conformations C(S)-s(Z)-5 and C2-s(E)-5 are transition states for the enantiomerization processes of C2-tz-5 and C2-tE-5, respectively, and lay 79.8 and 94.1 kJ/mol (PM3) and 108.3 and 107.4 kJ/mol (AM1) higher in energy than their corresponding twisted conformations. An alternative pathway for enantiomerization of C2-t(E)-5 via the anti-folded achiral intermediate C(i)-a(E) has a barrier of 56.0 kJ/mol (PM3) and 68.5 (AM1). An alternative pathway for enantiomerization of C2-t(Z)-5 via C2-t(E) and C(i)-a(E) has a barrier of 80.6 (PM3) and 75.8 (AM1) kJ/mol.","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":"7 6","pages":"261-9"},"PeriodicalIF":0.0,"publicationDate":"2002-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/10242430215701","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22294651","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: 5

Circular dichroism and the anomeric configuration of C-glycofuranosyl-2-phenyl-2H-1,2,3-triazoles. c -糖呋喃基-2-苯基- 2h -1,2,3-三唑的圆二色性和异构构型。

Enantiomer Pub Date : 2002-11-01 DOI: 10.1080/10242430215712

Mohammed A E Sallam

引用次数: 5