Short and high-yielding syntheses of enantiomerically pure (S)-(+) and (R)-(-)-abscisic acid are described. The syntheses proceed through key intermediates that preferentially recrystallise as single diastereoisomers for each enantiomer. This route allows the preparation of either enantiomer of abscisic acid in ca. 30% overall yield, and as demonstrated, gives access to an enantiomerically pure...

Chiral pesticides are important contaminants affecting the health and functioning of aquatic systems. The combination of stable isotope and enantiomer analysis techniques has been recently proposed to better characterize the fate of these contaminants in natural and engineered settings. We introduce a modeling approach with the aim of unifying and integrating the interpretation of isotopic and ...

CHIRALPAK QN-AX and QD-AX are anion exchanger chiral stationary phases providing specifi c enantioselectivity for acidic compounds. In this Application Note, we demonstrate that the application of these columns can be extended to supercritical fl uid chromatography (SFC) for enantiomer separation of acidic compounds. Using the advantages of the advanced technology of the Agilent 1260 Infi nity ...

The single handedness of biological molecules has fascinated scientists and laymen alike since Pasteur's first painstaking separation of the enantiomorphic crystals of a tartrate salt over 150 years ago. More recently, a number of theoretical and experimental investigations have helped to delineate models for how one enantiomer might have come to dominate over the other from what presumably was...

The aims of this study were to develop a transdermal patch for selective controlled delivery of the active S-enantiomer from racemic propranolol, and to evaluate its performance in vivo using Wistar rats. A molecularly imprinted polymer (MIP) thin-layer composited cellulose membrane with selectivity for S-propranolol was employed as the enantioselective-controlled release system. The effect of ...

The ability of optically pure (+)- and (-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene to initiate skin tumors in mice was determined with a two-stage tumorigenesis system. A single application of 50 to 200 nmoles of (+)- or (-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene to the backs of CD-1 mice followed by twice-weekly applications of 12-O-tetradecanoyl-phorbol-13-acetate revealed that t...

Numerous psychotropic drugs exist as a mixture of 2 mirror-image stereoisomers of each other, each called an enantiomer and the mixture called a racemate. Often the drug can be improved when only 1 of the enantiomers is administered.

The application of ultraviolet absorption detector (UV) and circular dichroism (CD) detectors in series in HPLC systems has been increased in recent years. In this work, an effective method to determine the enantiomer concentration on line in chiral drugs was explored. Ibuprofen (IBP) racemate was applied. The total concentration and concentration difference of S-(+)-IBP and R-(-)-IBP were obta...

The compound MG-1(R,S), (1-[2-hydroxy-3(4-phenyl-1-piperazinyl)propyl]-pyrrolidin-2-one, and its enantiomers were tested for electrocardiographic, antiarrhythmic and hypotensive activities. The racemic mixture (MG-1(R,S)) and its S-enantiomer significantly decreased systolic and diastolic blood pressure and possessed antiarrhythmic activity. The S-enantiomer displayed the greatest effect. The R...

Male Locusta hemolymph contains JH-esterase(s) and a JH-carrier protein with high affinity and low capacity that both interact enantioselectively with juvenile hormones. Exposure of racemic JH-I and JH-III results in preferential hydrolysis of the naturally configurated enantiomer of JH-I but the unnaturally configurated enantiomer of JH-III. The JH-carrier protein has a remark­ able specificit...