Bacterial phosphotriesterase (PTE) catalyzes the hydrolysis of a wide variety of organophosphate nerve agents and insecticides. Previous kinetic studies with a series of enantiomeric organophosphate triesters have shown that the wild type PTE generally prefers the S(P)-enantiomer over the corresponding R(P)-enantiomers by factors ranging from 1 to 90. The three-dimensional crystal structure of ...

The reactions with DNA and mutagenic activities toward Salmonella typhimurium TA 100 of the R,S,S,R and S,R,R,S enantiomers of anti-1,2,-dihydroxy-3,4-epoxy-1,2,3,4-tetrahydro-5-methylchrysene (anti-5-MeC-1,2-diol-3,4-epoxide), anti-5-MeC-7,8-diol-9,10-epoxide, and anti-6-MeC-1,2-diol-3,4-epoxide were compared because among these compounds only the R,S,S,R enantiomer of anti-5-MeC-1,2-diol-3,4-...

A common approach in resolving enantiomers of chiral basic drugs by capillary electrophoresis (CE) is to use cyclodextrins (especially their anionic derivatives) as chiral selector in the acidic buffer (pH ≤ 3) in normal or reversed (carrier) mode. Then, some organic modifiers are added to the buffer solution if the resolution is not satisfactory. In case of cetirizine (CTN), applying the same ...

Escitalopram is an antidepressant from the class called Selective Serotonin Reuptake Inhibitors (SSRI’s). SSRI’s were among the first pharmaceutical products commercialized as single enantiomers following a 1992 United States Food and Drug Administration (FDA) Policy Statement. The directive required a thorough investigation of the biological and toxicological properties of single enantiomers. ...

Both sexes of the bark beetle Dendroctonus brevicomis convert the (+) and (-) enantiomers of the tree terpene alpha-pinene to the corresponding enantiomers of trans-verbenol at about equal rates. (-)-trans-Verbenol inhibited the response of females, but not of males, to a mixture of attractive pheromone components. Since the female initiates the attack on a pine tree, (-)-trans-verbenol may pla...

A couple of enantiomers of novel chiral macrocyclic imines based on R/S-camphor were asymmetrically synthesized. Through the chiral macrocyclic ligands, enantiomers of nickel(II) coordination compounds were obtained. The chirality of the ligand was transferred to the nickel atom upon coordination, leading to predetermined configuration. The chiral ligands and corresponding nickel coordination c...

Racemic 1-(β-hydroxypropyl)azoles were prepared by solvent-free direct regioselective ring opening of 1,2-propylene oxide with imidazole or 1,2,4-triazole. Lipase-catalyzed transesterification of alcohols with vinyl acetate resulted in kinetic enantiomers resolution. Separated (S)-enantiomers of (+)-1-(1H-imidazol-1-yl)propan-2-ol and (+)-1-(1H-1,2,4-triazol-1-yl)propan-2-ol were quaternized wi...

Manual or computer assisted peak deconvolution on chromatograms of the racemate of 1-chloro-2,2-dimethylaziridine enantiomers GC was used to determine the peak areas of enantiomers in the racemate prior (AA,0, AB,0) and after the separation (AA, AB). These peak areas were used in the determination of apparent rate constants and apparent energy barrier to enantiomerization. Comparison of apparen...

A ligand exchange HPLC method for enantioseparation of ofloxacin enantiomers was developed by a using C8 stationary phase. Chromatographic separation was performed on a Zorbax-300SB-C8 column eluted with the mobile phase consisting of 15 % methanol in water containing 10mM phenylalanin and 5 mM CuSO4 at flow rate of 0.8 mL/min. The method was simple, rapid and suitable for routine analytical st...

The cis and trans enantiomers of the 1-(1-methylcyclohexyl)piperidines were prepared from either 3(R)- or 3(S)-methylcyclohexanone through the Bruylents reaction or a modified azide route, respectively. Separation of the intermediate amines 5 and 6 was achieved through chromatography or selective crystallization of a fumarate salt. The cis isomer 2b had about one-third of the affinity of phency...