enantiomeric excess


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enantiomeric excess

[ə¦nan·tē·ō¦mer·ik ek′ses]
(organic chemistry)
In an asymmetric synthesis, a chemical yield that contains more of the desired enantiomer than other products.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Any enantiomeric excess of the resulting lactones was determined by chiral gas chromatography with a capillary column, packed with enantiomerically pure [gamma]-cyclodextrin.
The specific rotation and enantiomeric excess of the resolved compounds were determined.
The enantiomeric excess values of flurbiprofen and flurbiprofen methyl ester (ee) were determined by HPLC (Agilent 1200) by using a chiral column (Chiralcel OD-H, 5 [micro]m, 250 mm x 4.6 mm) capable of separating the R- and Sisomers of flurbiprofen and flurbiprofen methyl ester, and the mobile phase was hexane/isopropanol/trifluoroacetic acid solution (98:2:0.1, V/V/V), at a flow rate of 1.0 mL/min.
Intraperitoneal administration of 50% enantiomeric excess (S75-R25) bupivacaine in postoperative analgesia of laparoscopic cholecystectomy.
The senior author recently became fully aware of the following strengths and weaknesses of the previously known lipase-catalyzed (S)-selective acetylation: (i) Enantiomerically pure (R)-2-methyl-1-alkanols can be reliably obtained from their racemic mixtures, although the maximally attainable yield (or recovery) of (R)-alcohols of [greater than or equal to] 98% ee is limited to 50% or, more specifically [less than or equal to] 25% if E = 10, [less than or equal to] 35% if E = 20, and [less than or equal to] 45% if E = 100, where E (enantiomeric ratio or selectivity factor) = ln[(1 - C)(1 - ee)]/ ln[(1 - C)(1 + ee)] and C and ee are the extent of conversion and the enantiomeric excess of the unreacted alcohol, respectively.
Steric effect played an important role in complex formation and achieving good ees as the enantiomeric excess of 1-phenylethanol obtained was maximum 81% for 8 (Entry 5 table 1), which helped us to access structure of the ligands in easy way.
The literature values for the enantiomeric excess (ee%) (obtained experimentally) are also shown in the tables as well as the enzyme Prelog behavior for the given substrate (further described below).
The crude product was purified by flash column chromatography, and the enantiomeric excess of the diol was determined by chiral gas chromatography (GC) analysis (Agilent HP Chiral-20B 30MX0.25MMX0.25UM GC Column).
To keep pace with this growth, researchers in drug discovery are seeking faster methods to enable higher throughput enantioselective analyses, enantiomeric excess determination and impurity profiling of chiral molecules.
The synthesis of SR, SS of 2-methylsulphinyl-1-indanone optically enriched in good yield and good enantiomeric excess determined by nuclear magnetic resonance technique employing the Kagan reagent as chiral shift agent.
Enantioselectivity was expressed as E value and was calculated by (1), ees (the enantiomeric excess of the substrate) was calculated by (2), and C was calculated by (3).
The low baseline noise and high ultraviolet sensitivity is suitable for application areas including enantiomeric excess and trace level analyses.