New oxindole carboxamides as inhibitors of DENV NS5 RdRp: Design, synthesis, docking and Biochemical characterization.

Dengue is a mosquito-borne disease caused by the dengue virus belonging to family flaviviridae and has grown to be a major global public health issue. Despite decades of effort, the global comeback of dengue is evidence of the inadequacy of present management techniques. Due to the loss of healthy lives and the depletion of scarce medical resources, dengue has a significant negative economic impact in underdeveloped countries. In recent years, research for tackling the incidences of dengue infection has increased. The structure of the viral genome has been deciphered with the non-structural protein, known as NS5 serving as a potential target. NS5 consisting of an MTase domain involved in RNA capping and an RdRp domain involved in viral replication. In the presented work, a series of new Oxindoline Carboxamide derivatives were designed and synthesized for inhibiting the viral RNA dependent RNA-polymerase (RdRp) activity of DENV. The novel compounds were put through tests including molecular docking and surface plasmon resonance (SPR) binding analysis to evaluate their affinity for the viral protein and their potential as novel inhibitors of the virus. From a total of 12 derivative compounds, four compounds OCA-10c, OCA-10f, OCA-10j & OCA-10i, were found to exhibit high affinity for NS5 RdRp, the KD values being 1.376 µM, 1.63 µM, 7.08 µM & 9.32 µM respectively. Overall, we report novel inhibitors of DENV RdRp activity with potential to be utilized against DENV for treating humans after further optimization.

Antiproliferative Activity of New Pyrazole-4-sulfonamide Derivatives: Synthesis and Biological Evaluation.

Pyrazole and sulfonamide constitute an important class of drugs, with several types of pharmacological agents. Facile synthesis of two new series of 3,5-dimethyl-1H-pyrazole-4-sulfonamide and 1,3,5-trimethyl-1H-pyrazole-4-sulfonamide derivatives was designed and synthesized. These pyrazole-4-sulfonamide derivatives are characterized by Fourier transform infrared (FT-IR), 1H NMR, 13C NMR, and elemental analysis, and their biological evolution data are presented. This paved way for the development of new pyrazole-4-sulfonamide derivatives. These compounds are tested for their in vitro antiproliferative activity against U937 cells by the CellTiter-Glo Luminescent cell viability assay using Mitomycin C. Cytotoxicity detection is based on the measurement of LDH activity, while these compounds did not exhibit cytotoxic activity on these cells. Half maximal inhibitory concentration (IC50) was calculated by Graph Pad Prism software for each dose. Their structure-activity relationships were obtained and discussed.

Valbenazine isomers and enantiomer determination by chiral normal phase liquid chromatography.

A novel, simple, specific, rapid, enantioselective normal phase chiral high-performance liquid chromatographic method with amylose-based Chiral Pak IG-3(250 × 4.6 mM) 3.0 µM column was developed and validated for separation and quantification of isomers and enantiomer of Valbenazine. The mobile phase composed of n-Heptane, isopropyl alcohol, dichloromethane, ethanol, and diethylamine in the ratio of 70:10:15:5:0.1 (V/V/V/VV) with a gradient flow rate was applied. The injection volume was 10 µl, and detection was carried out using a photodiode array detector at 282 nM. The column compartment was set at 35°C. The resolution between the enantiomer and isomers was found to be more than 2.0. The method was linear over the concentration range of limit of quantitation to 250% for isomers and enantiomers. The method was found to be robust with column temperature. The proposed chiral method is applicable for the determination of isomers and enantiomer of Valibenazine and was successfully used in the quality control of bulk drug manufacturing and pharmaceuticals.

Design, synthesis, anticancer evaluation and molecular docking studies of 1,2,3-triazole incorporated 1,3,4-oxadiazole-Triazine derivatives.

A new library of 1,2,3-triazole-incorporated 1,3,4-oxadiazole-triazine derivatives (9a-j) was designed, synthesized, and tested in vitro for anticancer activity against PC3 and DU-145 (prostate cancer), A549 (lung cancer), and MCF-7 (breast cancer) cancer cell lines using the MTT assay with etoposide as the control drug. The compounds exhibited remarkable anticancer activity, with IC50 values ranging from 0.16 ± 0.083 µM to 11.8 ± 7.46 µM, whereas the positive control ranged from 1.97 0.45 µM to 3.08 0.135 µM. Compound 9 d with a 4-pyridyl moiety shown exceptional anticancer activity against PC3, A549, MCF-7, and DU-145 cell lines, with IC50 values of 0.17 ± 0.063 µM, 0.19 ± 0.075 µM, 0.51 ± 0.083 µM, and 0.16 ± 0.083 µM, respectively.

Estimation of purity of antimicrobial lead compound sulfonamide-anthranilate derivative methyl-ester-toluene-sulfonamide using LC to develop a new drug application.

The newly synthesized lead molecule methyl-ester-toluene-sulfonamide is the combined derivative of sulfonamide-anthranilate. It was estimated by gradient elution using 0.1% triethylamine in water with pH 2.0 as mobile phase A and the mixture of acetonitrile and tetrahydrofuran in the ratio of 975:25 (v/v) as mobile phase B at a flow rate of 0.8 ml/min and 210 nm wavelength on an Agilent 1260 infinity series HPLC system equipped with a diode array detector. The column used was ACE 3 C18-PFP (250 × 4.6 mm, 3 µm i.d.) operating at 40°C. The gradient program was time (min)/% B: 0.0/50, 3.0/50, 15.0/70, 25.0/90, 30.0/90, 31/50, and 38/50. The method is simple, accurate, rapid, and selective. The method was linear with a concentration range of 1.6-240 µg/ml. The accuracy data obtained were 98.5-100.5%. The method validation data and quality by design-based robustness study results indicate that the developed method is robust and fit for routine use in the quality control laboratory. Therefore, the ready availability of the method can be useful in pharmaceutical new drug development.

Convenient synthesis, characterization and biological evaluation of novel 1-phenylcyclopropane carboxamide derivatives.

Small, strained ring molecules of phenylcyclopropane carboxamide have rigid, defined conformations and unique electronic properties. For these reasons many groups, seek to use these subunits to form biologically active compounds. Herein we report a generally applicable approach for preparing a small cyclopropane ring containing 1-phenylcyclopropane carboxamide derivatives to a wide range of the different aromatic compounds by α-alkylation of 2-phenyl acetonitrile derivatives with 1, 2-dibromo ethane in good yields followed by the conversion of cyano group to acid group by the reaction with concentrated hydrochloric acid. This obtained acid derivative undergoes acid amine coupling with various Methyl 2-(aminophenoxy)acetate to form 1-Phenylcyclopropane Carboxamide. These compounds possess distinct effective inhibition on the proliferation of U937, pro-monocytic, human myeloid leukaemia cell line while these compounds did not show cytotoxic activity on these cells. The structure-activity relationships of these compounds are discussed.

Identification and Characterization of the Isomeric Impurity of the Fungicide "Cyazofamid".

Identification and characterization of biproducts/ impurities present in agrochemicals are critical in view of their efficacy and safety towards public health. We herein present our study on identification and characterization of an impurity, 5-chloro-2-cyano-N,N-dimethyl-4-p-tolylimidazole-1-sulfonamide (2) present in the fungicide, "cyazofamid". Intermittent HPLC analysis of the reaction of substituted imidazole (1) with N,N-dimethylsulfamoyl chloride suggested that 2 is formed during the reaction. Isolation by preparative HPLC and characterization by NMR, LC/HRMS, MS/MS and single crystal XRD analysis confirmed 2 as an isomer of cyazofamid, wherein the N,N-dimethyl sulfonamide group was positioned on the other nitrogen of imidazole in close proximity to chloride group. Computational studies further supported the formation of 2 and ruled out the other possible isomeric structures.

Identification of novel C-15 fluoro isosteviol derivatives for GABA-AT inhibition by in silico investigations.

CONTEXT: The treatment of epilepsy is associated with the inhibition of γ-aminobutyric acid-aminotransferase (GABA-AT), which suppresses the concentration of a key neurotransmitter GABA. Isosteviol, a natural bioactive molecule, has been reported to possess an anticonvulsant property. In this work, we first reported a series of C-15 fluoro isosteviol analogs which are bearing different functional groups at C-16 to investigate the interactions with GABA-AT by applying molecular docking and molecular dynamic simulation approach. The results revealed that all fluoro isosteviol analogs displayed a greater binding affinity than references vigabatrin, an FDA-approved GABA-AT inactivator, and CPP-115, which has Orphan Drug Designation status, and positioned at the same binding site as references. Furthermore, molecular dynamic (MD) simulation studies on minimum (A1), maximum (E1) binding energy score of fluoro isosteviol analogs, and isosteviol (G1) revealed their stable complex formation in terms of RMSD, RMSF, RG, and hydrogen bond formation. All analogs were found to have drug-like nature, non-toxic, >80% absorption, and the majority tend to penetrate brain-blood-barrier (BBB). The investigations found in this study can help in the development of isosteviol derivatives as drugs for the treatment of epilepsy. METHODS: The two-dimensional (2D) ligand structures were drawn using ChembioDraw Ultra 14.0. Molecular docking with Autodock4 and molecular dynamic simulation with GROMACS version 2020.1 were performed. The CHARMM27 all-atom force field was applied for writing the topology. Biovia Discovery Studio DS2021 was used for viewing and analyzing the protein-ligand complexes. The data generated from molecular dynamic simulation trajectories were plotted using the Origin® 8 software. The Open Babel software was utilized for extracting SMILEs files of all the fluoro isosteviol analogs. The drug-likeness and ADMET of the molecules were evaluated by SwissADME and ADMETlab 2.0 web tools.

Molecular Hybrids of Pyazolo[3,4-b]pyridine and Triazole: Design, Synthesis and In Vitro Antibacterial Studies.

Antimicrobial resistance is on the rise, and there aren't enough new treatments to combat it. This might send the modern world back to the pre-antibiotic age. The molecular hybrids of pyrazolo[3,4-b]pyridine and triazole have been designed, synthesized, and analyzed for their drug-like molecule nature and in vitro analyses for their inhibition potentials against S. aureus and K. pneumoniae. The compounds 24 and 27 have been identified as the high potential molecules in this series based on in vitro experiments. Compound 24 has zone of inhibition values of 15 ± 0.82 mm and 14 ± 0.7 mm, whilst compound 27 has zone of inhibition values of 18 ± 0.95 mm and 16 ± 0.82 mm against S. aureus and K. pneumoniae, respectively. MIC and MIB values for compounds 24 and 27 against S. aureus and K. pneumoniae are 0.25 and 0.5, respectively.

Unique Quality by Design Approach for Developing HPLC and LC-MS Method for Estimation of Process and Degradation Impurities in Pibrentasvir, Antiviral Agent for Hepatitis C.

Pibrentasvir (PIB) was approved for treating hepatitis C patients. A specific, accurate, linear, robust, and stability-indicating method was developed and validated for determining degradation impurities present in the PIB drug substance by studying the quality by design (QbD) principles. All identified degradation impurities were separated with the stationary phase HALO C18, 150 mm × 4.6 mm, 2.7 µm. Mobile phase A contains pH 2.5 phosphate buffer and acetonitrile in the ratio of (70:30, v/v), and mobile phase B contains water and acetonitrile in the ratio of (30:70, v/v), respectively. The chromatographic conditions were optimized, such as flow rate of 0.8 mL/min, UV detection at 252 nm, injection volume of 20 µL, and column temperature of 40 °C. The proposed method was validated per the current ICH Q2 (R1) guidelines. The recovery study and linearity ranges were established from limit of quantification (LOQ) to 300% optimal concentrations. The method validation results were between 98.6% and 106.2% for recovery, and linearity r 2 was more than 0.999 for all identified impurities. The method precision results achieved below 5% relative standard deviation (RSD). The forced degradation results demonstrated that the drug was sensitive to chemical stress conditions. During the stress study, degrading impurities were identified by the LC-MS technique and the mechanism pathway. A QbD-based experimental design (DoE) approach was used to establish the robustness of the method.