A method for determining using a capillary gas chromatographic enantiomer ratio of trimethylcyclopentene derivatives represented by, the stationary phase used is heptakis (2,3-di -O- methyl -6-O-t - at least one compound selected from the group consisting -6-O-t- butyldimethylsilyl) -尾- ...
Performing the enantioseparation of 1 by HPLC using a chiral-pak IA column provided the enantiomers 1a and 1b with a ratio about 1:3. Given the reversed helicity rule of the 1Lb band ECD for the 7-hydroxy-2,3-dihydrobenzo[b]furan chromophore24, the negative 1Lb Cotton effect (CE) of...
1. An optically active compound of the formula (IIa) or (IIb): in which: X is selected from the group consisting of NH, O, S, SO, SO2, or CH2; n is 1, 2 or 3; * indicates an asymmetric carbon atom, wherein when n is 2 or 3, then * is R configuration; wherein when n...
1H NMR analysis of the imine diastereomer ratio can be conducted immediately after the aldehyde and amine have been mixed. The results correlate well with ee values determined by more traditional (and slower) methods. This approach may be broadly applicable to α-substituted aldehydes....
Based on enantiopure bis-bidentate N-donor ligands (-)/(+)-2,5-bis(4,5-pinene-2-pyridyl)pyrazine (L-R/L-s), a new pair of Nd-III enantiomers with the formula Nd(dbm)(3)L-R/s.2H(2)O (R-1 and S-1 being the isomers containing the L-R and L-s ligands, respectively, and...
the D-enantiomer of a O,O'-disubstituted tartaric acid, wherein the molar ratio of the L- to the D-enantiomer is from 80:20 to 95:5, and obtaining the (S)-nicotine of formula (l-b), or by adding O,O'-dibenzoyl-D-tartaric acid and obtaining the (R)-nicotine of formula (l-c...
The structure is exceptional in having nine independent formula units and an unbalanced set (ratio 4:5) of resolvable enantiomers. The difficulty in growing crystals of this material is consistent with its structural complexity.Erin WachterDepartment of ChemistryEdith C. Glazer...
Use of 3-amino-propan-1,2-diol derivs. of formula (I) and their salts, in the form of racemates, pure enantiomers or a mixt. of enantiomers in any ratio, is claimed for the treatment of disorders characterised by an elevated blood glucose level. R1 = phenyl opt. substd. by one or...
the D-enantiomer of a O,O'-disubstituted tartaric acid, wherein the molar ratio of the L- to the D-enantiomer is from 80:20 to 95:5, and obtaining the (S)-nicotine of formula (l-b), or by adding O,O'-dibenzoyl-D-tartaric acid and obtaining the (R)-nicotine of formula (l-c...
the D-enantiomer of a O,O'-disubstituted tartaric acid, wherein the molar ratio of the L- to the D-enantiomer is from 80:20 to 95:5, and obtaining the (S)-nicotine of formula (l-b), or by adding O,O'-dibenzoyl-D-tartaric acid and obtaining the (R)-nicotine of formula (l-c...