Direct Enantiomeric Resolution of Seventeen Racemic 1,4-Dihydropyridine-Based Hexahydroquinoline Derivatives by HPLC

Efficient kinetic resolution of racemic 3-nitro-2H-chromene derivatives catalyzed by Takemoto's organocatalyst.

Efficient kinetic resolution of racemic 3-nitro-2H-chromenes by bifunctional thiourea afforded optically active (R)-3-nitro-2H-chromene derivatives with moderate to good enantioselectivities, which simultaneously gave the multifunctional 3,4-diphenyl-3a-nitrobenzopyrano-[3,4-c]-pyrrolidine-1,1-dicarboxylate derivatives with four vicinal chiral carbon centers.

Semi-preparative enantiomeric separation of ofloxacin by HPLC.

A direct semi-preparative high performance liquid chromatography (HPLC) enantioseparation of ofloxacin was performed on chemically immobilized cyclodextrin derivative-mono (6A-azido-6A-deoxy)-per(p-chlorophenyl carbamoylated) β-CD chiral stationary phase. Conditions for semi-preparative separations were established using a 250 × 4.6 mm i.d. column and subsequently extended to a 250 × 10.0 mm i....

Resolution of racemic phenylalanine.

Phenylalanine has previously been resolved by fractional crystallization of the brucine salt of formyl-nn-phenylalanine (1) or of the cinchonine salt of benzoyl-nn-phenylalanine (2). Enzymatic methods have also been used for the resolution. According to the method of Gilbert, Price, and Greenstein (3), racemic phenylalanine is resolved by subjecting its Nchloroacetylated derivative to asymmetri...

Resolution of dihydropyridine calcium antagonist enantiomers using HPLC with ovoglycoprotein as a chiral stationary phase.

Formation of racemic crystals of transition metal complexes by grinding 1 : 1 mixtures of enantiomeric crystals.

Grinding a 1 : 1 enantiomeric mixture of chiral transition metal complex crystals and subsequent annealing afforded crystals of a racemic compound by diffusion and rearrangement of component molecules, without melting and without racemization of each enantiomeric species.