Chirality最新文献

An enantioselective voltammetric sensor (EVS) comprising a paste electrode made of graphitized thermal Carboblack C (CBPE) modified with a Ni(II) complex based on (S)-(2-aminomethyl)pyrrolidine and 3,5-di-tert-butylsalicylaldehyde was developed for the recognition and determination of naproxen (Nap) enantiomers. The proposed sensor was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS-SEM), Fourier-transform infrared spectroscopy (FT-IR), molecular dynamics and quantum chemical simulations, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) methods. Using the differential pulse voltammetry (DPV), the CBPE@(S)-Ni sensor was found to have good selectivity for Nap enantiomers (i_p1S/i_p1R = 1.43, i_p2S/i_p2R = 1.27 for the first/second peaks, respectively). The sensor demonstrates the highest sensitivity to (S)-Nap (6.44 and 6.90 μA/mM for the first and second peaks). The linear concentration range is from 5.0 × 10⁻⁵ to 1 × 10⁻³ M and from 2.0 × 10⁻⁴ to 1 × 10⁻³ M for (S)- and (R)-Nap, respectively, where the detection limits for the first and second peaks are 5.31 × 10⁻⁷ M and 4.96 × 10⁻⁷ M for (S)-Nap and 7.40 × 10⁻⁷ and 6.79 × 10⁻⁷ for (R)-Nap. The suggested sensor was successfully tested for the determination of Nap enantiomers in mixtures, in biological fluids, and in medicinal drug forms. In all the cases, the relative standard deviation (RSD) does not exceed 4.7%; the recovery percentage is in the range of 99.2%–101.3%.

In the fields of pharmaceuticals and biopharmaceuticals, chiral liquid chromatography techniques including high-performance liquid chromatography and ultra-performance liquid chromatography are frequently used to isolate, identify, separate, and quantify chiral isomers, including enantiomers and diastereomers (stereoisomers), due to the significant differences in biological activity and therapeutic effects of stereoisomers. The authors have provided a comprehensive overview of the fundamental principles necessary for using liquid chromatography to separate and accurately estimate chiral compounds that exhibit stereoisomerism (both enantiomers and diastereomers). The development strategies outlined include the selection of chromatographic conditions, optimization of sample preparation, evaluation of degradation pathways, establishment of system suitability criteria, and execution of method validation studies. Additionally, this article supports the development of robust and stability-indicating methods by applying one factor at a time and design of experiments concepts for chiral drugs and their chiral impurities in pharmaceuticals and biopharmaceuticals. The method validation attributes essential to evaluate the characteristics of the developed method were discussed in this write-up. The validation parameters include specificity, linearity, detection limit, quantitation limit, accuracy, precision, solution stability.

Carbazole, a natural alkaloid, has been recognized as an effective anticancer agent for over 40 years. However, only a limited number of carbazole-based compounds have received FDA approval for cancer treatment. Current cancer therapies are often associated with significant side effects, causing physical, emotional, and financial burdens for patients. Additionally, despite advancements, cancer prevention and treatment remain challenging due to suboptimal clinical outcomes. The development of new drugs is crucial for achieving safer and more effective cancer therapies. This review focuses on various carbazole derivatives and hybrid composites, highlighting their interactions with distinct receptors and their mechanisms of anticancer action, along with a general structure–activity relationship (SAR). It also emphasizes carbazole-based compounds employed in chemoprevention, which aim to delay or prevent malignant progression. By covering carbazole derivatives and their anticancer potential from 2013 to the present, along with their current clinical status, this study offers valuable insights and updates for researchers in the field.

We have recently celebrated the 150th anniversary of the tetrahedral carbon (1874–2024), as postulated by van't Hoff and Le Bel, who published their seminal breakthrough only 2-months apart, on September 5 and November 5, 1874, respectively. The concept is a fundamental pillar of structural chemistry and, if we may say so, of molecular sciences. How two young men in their early careers dared to disturb the established way of thinking constitutes the jumping-off of scientific theories as constructive elements, rather than arguments derived from experiments. Chirality makes no sense without geometry. Nor can we interpret a molecular scenario devoid of spatial considerations. All in all, a felicitous celebration to be highlighted.

2-Thiohydantoin derivatives, including different substitutions at N-1 and C-5 (5-methyl-, 5-isopropyl-, 1-acetyl-5-methyl-, and 1-acetyl-5-isopropyl-) (1–4, respectively), were synthesized by the known literature methods. In these synthetic pathways, it was reported that enantiomerically pure 2-thiohydantions were obtained in the absence of any solvent via the reaction of L-amino acids with thiourea (1&2) and via the reaction of L-amino acids with NH₄SCN and acetic anhydride (3&4). However, in this study, in contrary to the previous literature studies, racemic mixtures of 2-thiohydantoins were obtained although the same synthetic methods were used. The racemic nature of 2-thiohydantoin derivatives (1–4) was proved by using ¹H NMR analysis in the presence of (1R,2S)-(−)-ephedrine as a chiral auxiliary. In addition, the enantiomers of 3&4 were also resolved on chiral stationary phases by HPLC analyses. Furthermore, newly synthesized unsymmetrical chiral thioureas (S-1&S-2) and previously synthesized symmetrical ones (SS-3&SS-4) were used as chiral solvating agent (CSA) for the enantiodiscrimination of the thiohydantoins (5&6), previously reported. Optimal CSA/substrate ratios were determined for the best enantiodiscrimination.

Chirality plays a crucial role in the pharmacological activity of triazoles, a key scaffold in antifungal agents and various therapeutic applications. This study focuses on optimizing the enantiomeric resolution of chiral triazoles using supercritical fluid chromatography (SFC) and 10 different columns, either immobilized or coated, chlorinated or nonchlorinated, cellulose or amylose-based chiral stationary phases (CSPs). Four novel triazoles and two marketed ones (tebuconazole and hexaconazole) were separated to determine optimal resolution conditions. The best resolution was achieved using chlorinated amylose-based CSPs across the tested compounds. Optical rotation and X-ray crystallography were employed to determine the absolute configurations of the purified enantiomers.

The synthesis, structure, and circularly polarized luminescence (CPL) properties of axially chiral boron difluoride complexes are described. A series of optically pure bis (boron difluoride) complexes were prepared in 5 steps from commercially available (S)- or (R)-BINOL as starting materials. The complexes were found to exhibit similar yellow photoluminescence in solution, regardless of the type of substituents on the nitrogen atoms. Notably, for the complex with polyethylene glycol chains, homogeneous and transparent films were formed by the drop-cast method, showing intense CPL with a different sign from that of the solution state. Density functional theory (DFT) calculations were performed to understand their photophysical behavior including configuration-dependent CPL properties.