Enantiomeric recognition of racemic 4-aryl-1,4-dihydropyridine derivatives via chiralpak AD-H stationary phases.
The chromatographic chiral resolution of two new series of racemic 4-substituted-1,4-dihydropyridine derivatives was studied on a commercial Chiralpak AD-H column. Analytes without 5,5-dimethyl substituents (1-15) are more efficiently resolved than analytes with 5,5-dimethyl groups (16-30). The AD-H column discriminated between enantiomers through both hydrogen bonding attractions and π-π interactions. This interpretation is in accord with plots of the logarithm of separation factors, log(α), versus σ (Hammett-Swain substituent parameter) and σ(+) (Brown substituent constant) plots. By elucidating the effects of the remote substituents on these chiral separations, it was shown that the influence of π-π interaction forces increase when steric bulk effects act to decrease the hydrogen bonding attractive forces on the AD-H column.
Department of Chemistry, Mississippi State University, Mississippi, USA.
Zhi
Z
Dai
Charles U
CU
Pittman
Tingyu
T
Li
D000688:Amylose / Q000031:analogs & derivatives* / Q000737:chemistry; D004095:Dihydropyridines / Q000138:chemical synthesis / Q000737:chemistry*; D006860:Hydrogen Bonding; D008745:Methylation; D015394:Molecular Structure; D048448:Phenylcarbamates / Q000737:chemistry*; D013237:Stereoisomerism
D004095:Dihydropyridines; D048448:Phenylcarbamates; C080033:Chiralpak AD; C038806:1,4-dihydropyridine; D000688:Amylose