Separation of enantiomers of 4-aryldihydropyrimidines by direct enantioselective HPLC. A critical comparison of chiral stationary phases

Determination of absolute configuration in 4-aryl-3,4-dihydro-2(1H)-pyrimidones by high performance liquid chromatography and CD spectroscopy

“…9 This was done by simple collection of the eluting enantiomers from an analytical-type HPLC separation of the racemic material (for 7b, ␣ = 1.30, R s = 1.84; for 7c, ␣ = 1.51, R s = 3.12; for 7d, ␣ = 1.27, R s = 2.10). After the mobile phase was evaporated, both enantiomers were dissolved in MeOH and their CD spectra subsequently measured.…”

“…In the past, optically pure DHPMs were obtained by resolution of the corresponding racemic carboxylic acids via diastereomeric ammonium salts, 8 by separation of diastereomeric derivatives bearing chiral auxiliaries at N(3), [3][4][5] or by enantioselective HPLC. 9,10 In each case, the absolute configuration of the enantiomerically pure material had to be determined by single-crystal X-ray analysis of suitable diastereomeric derivatives. [3][4][5]8 In recent years, the combined use of enantioselective chromatographic separation techniques with chiroptical spectroscopic methods has been developed in order to determine the absolute configuration of chiral molecules.…”

Chiral separation by chromatographic and electromigration techniques. A Review

“…Hydrophobic parts of the analyte may be included into the hydrophobic basket and hydrogen bonds with the pendant arms as well as dipole stacking, ionic-, p-p interactions and steric repulsions are assumed to be the main interactions responsible for chiral recognition. Vancomycin [131] found application among others to the chiral separation of barbiturates, hydantoins, piperidine-2,6-dione and cyclic amides [136], dihydropyrimidinones [137], pyridone derivatives [138] and semi-synthetic ergot alkaloids [139]. A CSP based on vancomycin derivatized with 3,5-dimethylphenylisocyanate [131] showed different chiral recognition ability and resolved for example hydroxyzine and althiazide.…”

4-Aryldihydropyrimidines via the Biginelli Condensation: Aza-Analogs of Nifedipine-Type Calcium Channel Modulators

“…simulated moving bed chromatography) have gained importance in the preparation of single-enantiomer drugs and intermediates [28]. In a recent publication we reported the successful chromatographic enantioseparation of DHPM derivatives of type 4 using a variety of commercially available chiral stationary phases (CSPs) in normal-and reversed-phase analytical HPLC [29]. Out of 29 racemic DHPM analogues all but one were separated on at least one of the eight CSPs tested with separation coefficients ranging from 1.08 to 8.67.…”

“…For polycyclic DHPMs 11 for example, the use of Chiralcel OD-H as CSP and 2-propanol/n-heptane as mobile phase has proved to be an effective method for enantioseparation ( Figure 5). on Chiralcel OD-H [29].…”