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A tandem synthesis of 3-acetylcoumarinoindoles 5a, 5b, 5c, 5d, 5e in the presence of catalytic amount of l-proline in ethanol medium is reported. l-proline has been utilized as an efficient and eco-friendly catalyst for the of 3-cyanoacetylindoles 1a, 1b, 1c, 1d, 1e with 2-hydroxybenzaldehyde ( 2) to afford the corresponding substituted 3-(1 H-indol-3-yl)2-(2-hydroxybenzylidene)-3-oxopropanenitriles 3(a-e), which without isolation were treated with hot conc. HCl to afford 3-acetylcoumarinoindoles 4a, 4b, 4c, 4d, 4e in high yields. Subsequently, these were reacted with dimethyl sulfate in the presence of PEG-600 (Hyderabad, Andhra Pradesh, India) as an efficient and green solvent to afford the corresponding N-methyl-3-acetylcoumarinoindoles 5a, 5b, 5c, 5d, 5e in moderate yields. [ABSTRACT FROM AUTHOR]

An atom and step economic synthesis of multifunctional N,N'-(2-alkyl-1,3-diarylprop-1-ene-1,3-diyl)diacetamides employing a novel tandem aldol-double Ritter-type multicomponent one-pot reaction between aromatic aldehydes, enolizable ketones, and a nitrile source in the presence of 20mol% of BF3⋅Et2O is described. The reaction boosts operational simplicity, shortens reaction time, and has a simple work-up. [ABSTRACT FROM AUTHOR]

Abstract: Silica (SiO2) mono-layer and silica–alumina (SiO2–Al2O3) bi-layer thin films were developed on both SS304 and Ti thin foils by pulsed rf magnetron sputtering. The solar absorptance (α s) and IR emittance (ε ir) of the films were measured. Both α s and ε ir of SS304 and Ti were increased after depositing SiO2 and SiO2–Al2O3 bi-layer thin film. The ratio of solar absorptance and IR emittance (i.e. α s/ε ir) can be tailored in a large range e.g. 3.3–0.850 for SS and 3.66–1.085 for Ti which is useful for many spacecraft subsystems to tailor their operating temperatures. Further, the microstructure, surface morphology and topography of the films were investigated by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and atomic force microscopy. [Copyright &y& Elsevier]

The R,S-enantiomer impurity and diastereomer impurities (S,S-isomer and R,R-isomer) of the solifenacin (S,R-enantiomer) were effectively separated and quantified simultaneously utilizing normal-phase high-performance liquid chromatography with a chiral stationary phase consisting of amylose tris (3,5-dimethylphenylcarbamate) coated on silica-gel (Chiralpak, AD-H). The enantiomeric and stereo-selective separation was achieved within a run time of 35 minutes using a mobile phase of 'n-hexane, ethanol, and diethylamine' in an isocratic elution mode with a detection wavelength of 220 nm. The validation attributes assessed were accuracy (which showed excellent recoveries between 97.5% and 100.4%) and linearity (which was proven in the range of 0.081-1.275 μg.mL -1 , with a linear regression of 0.999). The stress testing experiments proved that the developed methodology by the HPLC technique has stability-indicating characteristics, as all closely eluting peak pairs were separated well with a resolution of 2.3 and without any interference. The proposed methodology was highly efficient in separating and simultaneously determining the chiral impurities (enantiomers and diastereomers) of the solifenacin in the release and stability sample analyses of drug substances and tablets in pharmaceutical formulations., (© 2023 Wiley Periodicals LLC.)

Montelukast sodium (MLS) is a leukotriene receptor antagonist that relieves asthma, bronchospasm, allergic rhinitis, and urticaria. A simple, robust, and stability-indicating normal phase high-performance liquid chromatography method was developed to separate and quantitatively estimate the S-enantiomer of MLS. The chiral separation was achieved using USP L51 packing material along with a mobile phase consisting of a solvent mixture (n-hexane, ethanol, and propionic acid), a flow rate of 1.0 mL/min, a detection wavelength of 284 nm, a column temperature of 30°C and an injection volume of 20 μL. The enantiomers peaks were well separated from the peaks of the placebo, diluting solvent, MLS, and its known impurities with a resolution of more than 2.2 and with no interference. Accuracy and linearity were studied in a range of 0.36-3.597 μg/mL (0.03%-0.30%), with good recoveries between 92.5% and 96.8% and a linear regression coefficient above 0.996. The suggested chiral chromatography method is being considered as an alternative and equivalent method to the United States Pharmacopeia and European Pharmacopeia monographs. The developed method was effectively employed for the study of release and stability samples of MLS. This HPLC method is also capable of separating and estimating the stereo-selective isomers (R- and S-enantiomers) of sulfoxide impurity of MLS in pharmaceutical medicine., (© 2023 Wiley Periodicals LLC.)

Lacosamide (LA) is an antiepileptic medicine that is used to treat tonic-clonic seizures, partial-onset seizures, mental problems, and pain. A simple, effective, and reliable normal-phase liquid chromatographic technique was developed and validated to separate and estimate the enantiomer of (S-enantiomer) LA in pharmaceutical drug substance and drug product. Normal-phase LC was performed using USP L40 packing material (250 × 4.6 mm, 5 μm) and a mobile phase of n-hexane and ethanol at 1.0 ml min -1 . The detection wavelength, column temperature, and injection volume used were 210 nm, 25°C, and 20 μl, respectively. The enantiomers (LA and S-enantiomer) were completely separated using a minimum resolution of 5.8 and accurately quantified without any interference in a 25-min run time. Accuracy study for stereoselective and enantiomeric purity trials was conducted between 10 and 200%, with recovery values ranging from 99.4 to 103.1% and linear regression values >0.997. The stability-indicating characteristics were assessed using forced degradation tests. The proposed normal-phase HPLC technique is an alternate approach to the official monograph methods (USP and Ph.Eur.) of LA, and it was successfully used in the evaluation of release and stability samples for both tablet dosage forms and pharmaceutical substances., (© 2023 John Wiley & Sons Ltd.)

The first, sensitive, and rapid chiral method was developed for enatioseperations and determination of cabotegravir and its enantiomeric impurities by using HPLC and LC-MS. Cabotegravir is an antiretroviral medication used for the treatment of HIV/AIDS approved by the food and drugs administration (FDA) in the year 2021. The cabotegravir chiral separation was achieved on the coated cellulose-tris (4-chloro-3-methyl phenyl carbamate) (CHIRALCEL OX-3R) column in HILIC mode and the total run time is less than 15 min. The effects of mobile phase composition, elution mode, and percentage of organic modifier as well as the effect of mobile phase-additives and column temperature were investigated on selectivity, resolution, and peak symmetry. The mobile phase consisted of acetonitrile and water with 0.1% (v/v) addition of formic acid additive with the flow rate of 1 mLmin -1 . UV detection was carried out at 220 nm. The calibration curves of cabotegravir and its enantiomers were linear over the concentration range of 0.04-1.125 µgmL -1 . The limits of detection and quantification for cabotegravir and its enantiomer (RS isomer) were ≤ 0.02 and ≤ 0.06, and the RR and SS-isomers limits were ≤ 0.02 and 0.03 µgmL -1 respectively. It was demonstrated that the proposed method is selective, precise, and robust. Finally, the validated method was applied for the determination and identification of cabotegravir and its chiral enantiomers in the bulk drugs by using HPLC and LC-MS techniques., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

Objective: Misoprostol is a synthetic prostaglandin that is related structurally to naturally occurring prostaglandin (PG), and it has been acknowledged as an effective inhibitor of gastric acid secretion when administered intravenously., Methods: In the present study, the novel application of 1,8-Diazabicyclo[5.4.0]undec-7-ene, a cyclic unsaturated amine [DBU] for the conversion of A-type Misoprostol (A-MP) to B-type Misoprostol (B-MP) via intramolecular isomerization., Results: The intramolecular isomerization process was successfully applied for the separation of enantio-pure isomers with no impurities using DBU., Conclusion: The chemical structures of A-MP and B-MP were confirmed using spectral analyses of 1H-NMR, 13C-NMR and Mass spectroscopy., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Amitriptyline hydrochloride is an antidepressant drug with sedative effects used to treat the symptoms of anxiety, agitation with depression and schizophrenia with depression. A reversed-phase high-performance liquid chromatography method was developed to separate and quantitatively determine the assay and four organic impurities of amitriptyline in tablet dosage form and bulk drugs using a C 18 column in an isocratic elution mode with mobile phase consisting of a mixture of pH 7.5 phosphate buffer and methanol. The pH conditions used in the chromatographic separation are discussed. The stability-indicating characteristics of the proposed method were proved using stress testing [5 m HCl at 80°C/1 h, 5 m NaOH at 80°C/1 h, H 2 O (v/w) at 80°C/1 h, 6% H 2 O 2 (v/v) at 25°C/1 h, dry heat at 105°C/24 h and UV-vis light/4 days] and validated for specificity, detection limit, quantitation limit, linearity, precision, accuracy and robustness. For amitriptyline and its four known organic impurities, the quantitation limits, linearity and recoveries were in the ranges 0.25-3.0 μg/ml (r 2  > 0.999) and 87.9-107.6%, respectively. The mass (m/z) spectral data of amitriptyline hydrochloride and its impurity are discussed. The proposed LC method is also suitable for impurity profiling and assay determination of amitriptyline in bulk drugs and pharmaceutical formulations., (© 2022 John Wiley & Sons Ltd.)

Montelukast sodium (MLS) is a leukotriene receptor antagonist drug used in the treatment of asthma, bronchospasm, allergic rhinitis and urticaria. A reversed-phase high performance liquid chromatography method was developed to separate, identify and quantitative determination of MLS and its eight known organic impurities in tablet dosage form using a C 18 column and mobile phases consisting of a gradient mixture of pH 2.5 phosphate buffer and acetonitrile. The stability-indicating character of the developed method was proven using stress testing (1 m HCl at 80°C/30 min, 1 m NaOH at 80°C/30 min, H 2 O at 80°C/30 min, 3% H 2 O 2 at 25°C/1 min, dry heat at 105°C/10 h and UV-vis light/4 days) and was validated for specificity, quantitation limit, linearity, precision, accuracy and robustness. For MLS and its eight known impurities, the quantitation limits, linearity and recoveries were 0.015-0.03 μg/ml, correlation coefficient > 0.997 (R 2  > 0.995) and 85.5-107.0%, respectively. The developed chromatographic method is suitable for impurity profiling and also for assay determination of MLS in bulk drugs and pharmaceutical formulations. The mass values (m/z) of newly formed degradation products (DP1 and DP2) of montelukast sodium were identified using liquid chromatography-mass spectrometry., (© 2022 John Wiley & Sons, Ltd.)