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Asymmetric redox reactions in human liver stereoselective oxidation of optically active dihydrohaloperidols, dihydrobromoperidols and stereospecific reduction of haloperidol and bromoperidol. 人肝脏中光学活性二氢氟哌啶醇、二氢溴哌啶醇立体选择性氧化及氟哌啶醇和溴哌啶醇立体特异性还原的不对称氧化还原反应。
Enantiomer Pub Date : 2000-01-01
M Takeshita, M Miura, T Ohkubo, K Sugawara
{"title":"Asymmetric redox reactions in human liver stereoselective oxidation of optically active dihydrohaloperidols, dihydrobromoperidols and stereospecific reduction of haloperidol and bromoperidol.","authors":"M Takeshita,&nbsp;M Miura,&nbsp;T Ohkubo,&nbsp;K Sugawara","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The stereoselective oxidation of dihydrohaloperidols (3a, b) and dihydrobromoperidols (4a, b), which are the main metabolites of haloperidol (1) and bromoperidol (2) in humans, respectively, were pharmacokinetically investigated using human liver microsomes and human cytochrome P450(CYP) isoenzymes expressed in the human cell line. The oxidation rates of the (R)-isomers (3a and 4a) in the human liver microsomes were faster than those of the (S)-isomers (3b and 4b), and the R/S enantiomeric ratios of 3 and 4 for intrinsic clearance (Vmax/Km) were 1.40 and 3.10, respectively, showing that stereoselective oxidation occurred in human liver. Concerning the involvement of the CYP isoenzymes in this oxidative pathway, the (R)-isomers (3a and 4a) were catalyzed by both CYP3A4 and CYP2D6, however, the (S)-isomers (3b and 4b) were catalyzed only by CYP3A4.</p>","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21701414","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: 0
A comparative study of factors affecting chiral separations under reversed-phase conditions using cellulosic and Pirkle-type chiral selectors. 纤维素和皮尔克尔型手性选择器反相条件下手性分离影响因素的比较研究。
Enantiomer Pub Date : 2000-01-01
L Tang, D Xiang, J A Blackwell
{"title":"A comparative study of factors affecting chiral separations under reversed-phase conditions using cellulosic and Pirkle-type chiral selectors.","authors":"L Tang,&nbsp;D Xiang,&nbsp;J A Blackwell","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Limited studies have been conducted in reversed-phase chiral chromatography despite the relevance to water soluble chiral analytes. Systematic investigation and interpretation of factors affecting chiral separation in reversed-phase LC is crucial to efficient chiral method development. Two of the most useful chiral stationary phases (CSPs), a cellulosic (Chiralcel OJ-R) and a Pirkle-type (Chirex 3005), were chosen as the chiral selectors in this study to systematically investigate the factors affecting chiral separation of a series of Fmoc-amino acids. The effects of temperature, pH, buffer concentration, buffer type and organic modifiers on retention and chiral selectivity were compared between the cellulosic and the Pirkle-type selectors. Temperature affected retention and selectivity, as predicted by thermodynamics, using both types of chiral selectors. On the cellulosic CSP, buffer pH was the only factor which caused a significant change in chiral selectivity, while several factors, including buffer concentration and organic modifier type, affected chiral selectivity on the Pirkle-type CSP. The results also indicated that the cellulosic CSP had a retention mechanism analogous to conventional reversed-phase LC, however, the Pirkle-type selector appeared to show a mixed mode retention mechanism for these analytes.</p>","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21948758","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: 0
HPLC resolution of the enantiomers of dihydroxyphenylalanine and selected salsolinol derivatives using sulfated beta-cyclodextrin. 硫酸-环糊精高效液相色谱法测定二羟基苯丙氨酸和沙索林醇衍生物的对映体。
Enantiomer Pub Date : 2000-01-01
K McMurtrey, C Strawbridge, J McCoy
{"title":"HPLC resolution of the enantiomers of dihydroxyphenylalanine and selected salsolinol derivatives using sulfated beta-cyclodextrin.","authors":"K McMurtrey,&nbsp;C Strawbridge,&nbsp;J McCoy","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>D- and L-dihydroxyphenylalanine (D- and L-DOPA) and enantiomers of the tetrahydroisoquinoline alkaloids salsolinol (SAL), 1-carboxysalsolinol (1-CSAL), and cis-3-carboxysalsolinol (3-CSAL) were chromatographed using sulfated beta-cyclodextrin (S-beta-CD) as a chiral selector in mobile phases with conventional reversed-phase ODS columns. S-beta-CD is a very effective chiral selector for SAL and 3-CSAL, less effective although still useful for resolving D- and L-DOPA, and gives only meager separation of the optical isomers of 1-CSAL. Stoichiometries of the complexes which form between S-beta-CD and SAL enantiomers are 1:1. Interactions between carboxylated substances and S-beta-CD appears to be more complex. Retention of the solutes studied is characterized by favorable negative enthalpy and unfavorable negative entropy changes. Enthalpy changes outweigh entropy values.</p>","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21950450","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: 0
Optical resolution of phosphorus containing calix[4]arenes by additive RP HPLC method. 添加剂反相高效液相色谱法拆分含磷杯[4]芳烃。
Enantiomer Pub Date : 2000-01-01
O I Kalchenko, M O Tairov, M O Vysotsky, J Lipkowski, V I Kalchenko
{"title":"Optical resolution of phosphorus containing calix[4]arenes by additive RP HPLC method.","authors":"O I Kalchenko,&nbsp;M O Tairov,&nbsp;M O Vysotsky,&nbsp;J Lipkowski,&nbsp;V I Kalchenko","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The RP HPLC method (LiChrosorb RP18 or Separon SGX C18 column, acetonitrile-water 86:14 v/v mobile phase) was applied for enantiomeric separation of topologically chiral 5-bromo-25,26-bis(diethoxyphosphoryl)calix[4]arene 9 or 25-ethyl-26-dihydroxyphosphoryl-calix[4]arene 5. Separation of calixarene 9 was achieved by the addition of D-(-)-tartaric acid which formed hydrogen bonded diastereomeric associates with 9 to the mobile phase. Calixarenephosphoric acid 5 was transformed into diastereomeric salt 6 by addition of L-(-)-alpha-phenylethylamine before RP HPLC separation.</p>","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21950451","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: 0
NMR methods for determination of enantiomeric excess. 对映体过量测定的核磁共振方法。
Enantiomer Pub Date : 2000-01-01
R Rothchild
{"title":"NMR methods for determination of enantiomeric excess.","authors":"R Rothchild","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>With the dramatic recent growth in importance of asymmetric syntheses, new applications or approaches for analyses of enantiomeric excess (% e.e.) of samples continue to become more essential. Nuclear magnetic resonance (NMR) spectroscopy provides a wide range of powerful methods which are complementary to chromatographic or electrophoretic-based approaches. This present review focuses on representative and selective recent examples (through mid-1999) of English language reports on NMR methods for % e.e. determination.</p>","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21966417","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: 0
A novel chiral stationary phase in HPLC: optical resolution of racemic amino compounds by (1-->6)-2,5-anhydro-3,4-di-O-ethyl-D-glucitol bound on silica gel. 一种新的HPLC手性固定相:硅胶结合(1- >6)-2,5-无水-3,4-二- o-乙基-d -葡萄糖醇光学拆分外消旋氨基化合物。
Enantiomer Pub Date : 2000-01-01
S Umeda, T Satoh, K Saitoh, H Kanai, M Kamada, K Yokota, T Kakuchi
{"title":"A novel chiral stationary phase in HPLC: optical resolution of racemic amino compounds by (1-->6)-2,5-anhydro-3,4-di-O-ethyl-D-glucitol bound on silica gel.","authors":"S Umeda,&nbsp;T Satoh,&nbsp;K Saitoh,&nbsp;H Kanai,&nbsp;M Kamada,&nbsp;K Yokota,&nbsp;T Kakuchi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>[(1-->6)-2,5-Anhydro-3,4-di-O-ethyl-D-glucitol]-bound silica gel (CSP 4a), which was prepared by a two-step reaction, was used as a chiral stationary phase in high-performance liquid chromatography. The chiral recognition ability of the CSP 4a for racemates was examined using aq. NaClO4 (pH 2) and aq. NaClO4 (pH 2)/CH3CN as the eluents. For the resolution of amino acids and amino acid methyl esters, the D-isomers were eluted first. The separation factors of many of the racemates were 1.1-1.4, and the resolution factors were 0.59-7.75. This stationary phase showed a relatively high-resolving power toward compounds having a bulky substituent on the chiral carbon, such as phenylglycine and 1-(1-naphthyl)ethylamine.</p>","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21966418","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: 0
Metabolism of ethyl tiglate in apple fruits leads to the formation of small amounts of (R)-ethyl 2-methylbutanoate. 苹果果实中丁酸乙酯的代谢导致少量(R)- 2-甲基丁酸乙酯的形成。
Enantiomer Pub Date : 2000-01-01
T Hauck, B Weckerle, W Schwab
{"title":"Metabolism of ethyl tiglate in apple fruits leads to the formation of small amounts of (R)-ethyl 2-methylbutanoate.","authors":"T Hauck,&nbsp;B Weckerle,&nbsp;W Schwab","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>(S)-Ethyl 2-methylbutanoate is an important aroma compound in apples and serves as an indicator for genuineness of apple products due to its high optical purity of greater than 98% enantiomeric excess [T. Koenig and P. Schreier, Zeitsch. Lebensm.-Unters. Forsch. A, 1999, 208, 130-133; K. Schumacher et al., J. Agric. Food Chem., 1998, 46, 4496-4500]. The origin of minor amounts of (R)-ethyl 2-methylbutanoate is unknown as naturally occurring (+)-isoleucine, the proposed precursor of (S)-ethyl 2-methylbutanoate is enantiomerically pure. Since ethyl (E)-2-methyl-2-butenoate (ethyl tiglate) was recently discovered as a natural apple constituent and hydrogenation activity in apples was demonstrated we proposed ethyl tiglate as a precursor of (R)-ethyl 2-methylbutanoate. D4-3,4,4,4-ethyl tiglate was synthesized and was injected into ripe apple fruits (cv. Golden Delicious, Red Delicious and Granny Smith). After 3, 6, and 12 days apple volatiles were isolated by solid phase extraction on XAD-2 and the metabolites formed from D4-3,4,4,4-ethyl tiglate were analyzed by capillary gas chromatography-mass spectrometry (GC-MS). Ethyl 2-methylbutanoate, 2-methylbutyl acetate, 2-methylbutanol, and 2-methylbutanoic acid were identified as major transformation products. Chiral evaluation of the metabolites by multidimensional GC-MS revealed enantiomeric excesses ranging from 43% (S) to 30% (R) depending on the apple cultivar, sampling date and metabolite. The data show for the first time that the natural apple constituent ethyl tiglate can serve as a source for (R)-2-methylbutanol derivatives.</p>","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21966421","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: 0
Effective resolution of chiral 1,1':5',1"-ternaphthalene-2,2',6',2"-tetrol through camphorsulfonylation, recrystallization and reductive desulfonylation 通过樟脑磺化、重结晶和还原性脱硫有效地分离手性1,1′:5′，1′-对萘-2,2′，6′，2′-四苯醚
Enantiomer Pub Date : 2000-01-01
Sugimura, Wada, Tai
{"title":"Effective resolution of chiral 1,1':5',1\"-ternaphthalene-2,2',6',2\"-tetrol through camphorsulfonylation, recrystallization and reductive desulfonylation","authors":"Sugimura,&nbsp;Wada,&nbsp;Tai","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Optical resolution of the title compound, TERNOL (1), having bis-bidentate sites of axial chiralities was succesful. A racemic mixture of 1 was converted to the tetracamphorsulfonate 2 in high yield, and a single recrystallization of 2 under kinetic conditions effectively separated the diastereomers. The crystal part obtained in 44% yield consisted of (S,S)-2 of 96% diastereomer excess (de), and the solution part (50% yield) contained (R,R)-2 of 96% de. An additional recrystallization of the each part resulted in diastereomerically pure 2 in high yield. Hydride reduction of the ketones in the camphorsulfonyl groups of 2 caused smooth intramolecular transesterification, and enantiomerically pure (R,R)-1 and (S,S)-1 were obtained in good yields.</p>","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21613051","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: 0
Silver(I)-catalyzed asymmetric Mukaiyama aldol reaction 银(I)催化不对称Mukaiyama醛醇反应
Enantiomer Pub Date : 2000-01-01
Ohkouchi, Yamaguchi, Yamagishi
{"title":"Silver(I)-catalyzed asymmetric Mukaiyama aldol reaction","authors":"Ohkouchi,&nbsp;Yamaguchi,&nbsp;Yamagishi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Cationic Ag(I)-BINAP complex has been shown to be an effective catalyst for Mukaiyama aldol reaction between aldehyde and silyl enol ether derivatives. AgPF6-BINAP is very active in this reaction and can achieve high enantiomeric excess under mild conditions. Addition of a small amount of water enhanced the reactivity to suggest the contribution of enolate anion intermediate. AgOAc-BINAP, which in noncationic species, showed an extraordinary high activity although %ee was low.</p>","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21613056","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: 0
Enantioresolution and absolute stereochemistry of omicron-substituted diphenylmethanols 微米取代二苯基甲醇的对映体拆分和绝对立体化学
Enantiomer Pub Date : 2000-01-01
Kuwahara, Watanabe, Harada, Koizumi, Ohkuma
{"title":"Enantioresolution and absolute stereochemistry of omicron-substituted diphenylmethanols","authors":"Kuwahara,&nbsp;Watanabe,&nbsp;Harada,&nbsp;Koizumi,&nbsp;Ohkuma","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>omicron-Substituted diphenylmethanols were enantioresolved by the method of chiral dichlorophthalic acid amide, yielding enantiopure alcohols. Their absolute configurations were unambiguously determined by X-ray crystallography of chiral dichlorophthalate esters.</p>","PeriodicalId":11752,"journal":{"name":"Enantiomer","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21613060","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: 0
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