This study investigated the enantioselective metabolism of the chiral fungicide simeconazole in rat liver microsomes. The absolute configurations of the two enantiomers were determined to be S-(+)-simeconazole and R-(-)-simeconazole. The half-life of S-(+)-simeconazole was 2.7 min, while that of R-(-)-simeconazole reached 25.3 min; the elimination half-life of R-(-)-simeconazole was approximately 9.4 times longer than that of the S-(+)-enantiomer. Such remarkable enantiomeric discrepancy originates from the markedly higher V max of S-(+)-simeconazole (1.7836 mu M/min/mg) versus R-(-)-simeconazole (0.686 mu M/min/mg). Their K m values were comparable (5.93 mu M and 6.80 mu M, respectively), suggesting similar substrate binding affinity toward metabolic enzymes. Accordingly, the intrinsic clearance (CLint) of S-(+)-simeconazole (300.17 mL/min/mg) was three times that of R-(-)-simeconazole (101.47 mL/min/mg). Chemical inhibition assays verified that CYP3A2 serves as the predominant metabolic isoform for S-(+)-simeconazole, with an inhibition efficiency up to 98%. Molecular docking results demonstrated that S-(+)-simeconazole binds to CYP3A2 with lower binding energy and stronger hydrophobic interactions, whereas R-(-)-simeconazole preferentially interacts with CYP2D2. A total of five Phase I metabolites originating from hydroxylation, demethylation and oxidation reactions were characterized. Toxicity prediction via the TEST software revealed that the primary metabolites exhibit lower toxicity to fathead minnows yet higher toxicity to rats compared with the parent simeconazole. This work offers fundamental experimental evidence for the metabolic behavior and toxicological risk assessment of simeconazole enantiomers.
A novel pi-conjugated chiral system, BT2T4-(CH2OH)(2), derived from the atropisomeric scaffold 2,2 '-bis[2-(5,2 '-bithienyl)]-3,3 '-bithianaphthene (BT2T4), was synthesized to provide terminal hydroxymethyl groups for further functionalization. Baseline enantioseparation was achieved by high-performance liquid chromatography using the immobilized polysaccharide-derived Chiralpak IB chiral stationary phase under medium-polarity mobile-phase conditions, which ensured adequate analyte solubility while maintaining excellent chiral recognition. The optimized protocol allowed the isolation of the individual enantiomers in high enantiomeric purity (ee > 99%). The absolute configuration of the separated enantiomers was assigned through a direct correlation between on-line CD detection and CD spectra, providing a reliable stereochemical readout. Under specific synthetic conditions, additional minor species were detected; however, their formation was found to depend on reaction and handling parameters, such as the solvent, and can be minimized by conducting both the synthesis and storage in dichloromethane. Overall, BT2T4-(CH2OH)(2) represents a chiral pi-conjugated platform that offers potential applications in enantioselective recognition and in the development of chiroptical and sensing materials.
Fourteen flavonoids (1-12, 19, and 20) and six 2-arylbenzofurans (13-18), consisting of 10 chiral and 10 achiral compounds, were isolated and identified from the leaves of the famous medicinal plant Morus alba. Nine flavonoids (1-9) of the 10 chiral molecules were further analyzed and separated into the respective enantiomers by chiral HPLC, with the absolute configurations assigned via electronic circular dichroism analysis, which has clarified the puzzles on their optical/enantiomeric purity and configurational assignment in the previous reports. Most isolates showed significant inhibitory activity against the diabetic target alpha-glucosidase, and the binding mode of compound 13 with the enzyme was further explored, which identified it as a mixed-type inhibitor.
ABSTRACT Chiral high‐performance liquid chromatography (HPLC) is commonly used for the separation of enantiomeric compounds. We assessed the performance of 22 chiral HPLC columns from various manufacturers to determine their efficiency in separating enantiomers. A total of 30 racemic analytes (comprising acidic, neutral, and basic compounds) were analyzed using a gradient strategy of 80%–20% aqueous over 20 min. The columns were ranked based on the number of analytes they were able to separate, the resolution achieved for each enantiomer pair separation, and a combination of both parameters for each of the compound groups. The columns that achieved the highest number of enantiomer separations were the Lux i‐Amylose‐3 for acidic compounds and the MAC‐MOD Chiral Amy‐6 for neutral and basic compounds with the MAC‐MOD Chiral Amy‐6 being the column with the most enantiomers separated. The column that achieved higher resolution separations was the MAC‐MOD Chiral Amy‐6 for all types of compounds. When considering both parameters, the highest ranking columns were the Lux i‐Amylose‐3 and the MAC‐MOD Chiral Amy‐6 for acidic compounds and the MAC‐MOD Chiral Amy‐6 for neutral and basic compounds with the MAC‐MOD Chiral Amy‐6 being the highest ranked overall. Following data collection and analysis, a hierarchical list was created based on the highest probability of success for future screenings.
ABSTRACT A novel π‐conjugated chiral system, BT 2 T 4 –(CH 2 OH) 2 , derived from the atropisomeric scaffold 2,2′‐bis[2‐(5,2′‐bithienyl)]‐3,3′‐bithianaphthene ( BT 2 T 4 ), was synthesized to provide terminal hydroxymethyl groups for further functionalization. Baseline enantioseparation was achieved by high‐performance liquid chromatography using the immobilized polysaccharide‐derived Chiralpak IB chiral stationary phase under medium‐polarity mobile‐phase conditions, which ensured adequate analyte solubility while maintaining excellent chiral recognition. The optimized protocol allowed the isolation of the individual enantiomers in high enantiomeric purity (ee > 99%). The absolute configuration of the separated enantiomers was assigned through a direct correlation between on‐line CD detection and CD spectra, providing a reliable stereochemical readout. Under specific synthetic conditions, additional minor species were detected; however, their formation was found to depend on reaction and handling parameters, such as the solvent, and can be minimized by conducting both the synthesis and storage in dichloromethane. Overall, BT 2 T 4 –(CH 2 OH) 2 represents a chiral π‐conjugated platform that offers potential applications in enantioselective recognition and in the development of chiroptical and sensing materials.
