Bamford-Stevens reaction assisted synthesis of styrene C-glycosides

Modification of carbohydrates and their analogs is hindered due to multi-step synthetic methodologies involving selective protection and deprotection of multiple hydroxyl groups present in the molecule. A highly efficient route for the synthesis of 1-phenyl-2-(β-D-glycopyranosyl)ethenes has been developed from native sugars, which neither requires protection/deprotection of the hydroxyl groups nor use of any metal/metal ions. The key step of the developed methodology is the use of Bamford-Stevens reaction which led to the formation of the desired compounds in moderate to high yields in three steps only.     

K2S2O8-mediated decarboxylative oxysulfonylation of cinnamic acids: A transition-metal-free synthesis of β-keto sulfones

A new paradigm of the oxidative decarboxylative sulfono functionalization of cinnamic acids with sulfinate salts mediated by K₂S₂O₈ under aerobic conditions to afford synthetically and biologically relevant β-keto sulfones has been described. It is the first report on the transition-metal-free synthesis of β-keto sulfones from cinnamic acids, which employs environmentally benign, readily available and inexpensive starting materials and oxidants, viz. air and K₂S₂O₈.     

Chemical and biological evaluation of essential oil from Saussurea costus (Falc.) Lipsch. from Garhwal Himalaya collected at different harvesting periods

The purpose of this study is the determination of chemical composition and antioxidant activity of essential oils (EOs) from Saussurea costus (Falc.) Lipsch. Roots have been collected on December of the first plant year (IY) and in April, August and December of the third plant year (I, 6B, D7). A GC analysis was carried out for achieving this purpose. Subsequently, total polyphenol content (TPC) and antioxidant activity measured by DPPH, FRAP and BCB assays were evaluated. Three different statistical methods: Relative Antioxidant Capacity Index (RACI), Pearson’s correlation coefficient (r) and PCA, were used to compare results obtained and underline EO relationships. From the results obtained, it was possible to observe how the collection period of the EO, in particular both the month and the year of collection, influences the metabolite profile.     

Our Contributions in Synthesis of Diverse Heterocyclic Scaffolds by Using Mixed Oxides as Heterogeneous Catalysts

This personal account mainly introduces and reviews our recent contributions in developing different catalyst materials involving mixed oxides and their scope as renewable catalysts in multicomponent reactions to synthesize various novel heterocyclic scaffolds under green conditions. The application of various mixed oxides and their composites in the organic synthesis is emphasized through this review, in order to reveal the versatility, scope and importance of mixed oxides and their interactions during the reaction. We have also briefed the limitations of mixed oxides as catalysts, to put forward the broader prospective in the field.     

Latent Fingerprint Imaging Using Dy and Sm Codoped HfO2 Nanophosphors: Structure and Luminescence Properties

The development of latent fingerprints (LFPs) detected at the site of crime is considered as an imperative physical evidence in forensic investigations. Herein, a rapid and cost‐effective approach using nonhazardous Dy and Sm codoped HfO₂ nanophosphors is demonstrated to be utilized for LFP imaging. Sol–gel method can produce Dy and Sm codoped HfO₂ of monoclinic phase with crystallite size ranging from ≈10 to 25 nm. While selected area electron diffraction and lattice spacing calculated from high‐resolution transmission electron microscopy confirm monoclinic phase, Le‐Bail profile refinement of X‐ray diffraction (XRD) patterns demonstrate an exponential increase in lattice volume with incorporating various concentrations of Dy and Sm in HfO₂ lattice. Exciting Dy and Sm codoped HfO₂ with 393 nm photoluminescence spectra show emissions in blue, yellow, and near red regions emerging primarily due to energy transfer from Dy³⁺ to Sm³⁺ through multipolar interaction suggested by time resolved decay spectra. Combining excitation and emission spectra, an energy band diagram is proposed. Owing to excellent emissions, Dy and Sm codoped HfO₂ are explored for LFP imaging with good selectivity and resolution over multivariate surfaces like float glass and aluminum foil. The third‐level details like enclosure and termination–bifurcation are extracted due to nanosized nature of particles.     

Phase transition in YbAl<Subscript>3</Subscript>C<Subscript>3</Subscript>

¹⁷⁰Yb M?ssbauer spectroscopy, temperature dependent X-ray, magnetisation and specific heat data are presented in the hexagonal intermetallic YbAl₃C₃, in order to shed light on the isostructural transition occurring near 80 K and to investigate the electronic state of the Yb ion above and below the transition. In the low temperature phase, we find that there occurs an atomic rearrangement in the hexagonal unit cell, leading to a strong symmetry lowering at the Yb site. We show that no magnetic ordering of the Yb³⁺ moments occurs down to 0.04 K, and we discuss this finding in terms of 4f-conduction electron hybridisation and geometric frustration.     

Band-gap engineering of La_(1-x)Nd_xAlO_3(x = 0,0.25,0.50,0.75,1)perovskite using density functional theory:A modified Becke Johnson potential study

The structural,electronic,and magnetic properties of the Nd-doped Rare earth aluminate,La_(1-x)Nd_xAlO_3(x = 0%to 100%) alloys are studied using the full potential linearized augmented plane wave(FP-LAPW) method within the density functional theory.The effects of the Nd substitution in La AlO_3 are studied using the supercell calculations.The computed electronic structure with the modified Becke–Johnson(m BJ) potential based approximation indicates that the La_(1-x)Nd_xAlO_3 alloys may possess half-metallic(HM) behaviors when doped with Nd of a finite density of states at the Fermi level(E_F).The direct and indirect band gaps are studied each as a function of x which is the concentration of Nddoped La AlO_3.The calculated magnetic moments in the La_(1-x)Nd_xAlO_3 alloys are found to arise mainly from the Nd-4f state.A probable half-metallic nature is suggested for each of these systems with supportive integral magnetic moments and highly spin-polarized electronic structures in these doped systems at E_F.The observed decrease of the band gap with the increase in the concentration of Nd doping in La AlO_3 is a suitable technique for harnessing useful spintronic and magnetic devices.     

Computational Analysis Reveals Monomethylated Triazolopyrimidine as a Novel Inhibitor of SARS-CoV-2 RNA-Dependent RNA Polymerase (RdRp)

The human population is still facing appalling conditions due to several outbreaks of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) virus. The absence of specific drugs, appropriate vaccines for mutants, and knowledge of potential therapeutic agents makes this situation more difficult. Several 1, 2, 4-triazolo [1, 5-a] pyrimidine (TP)-derivative compounds were comprehensively studied for antiviral activities against RNA polymerase of HIV, HCV, and influenza viruses, and showed immense pharmacological interest. Therefore, TP-derivative compounds can be repurposed against the RNA-dependent RNA polymerase (RdRp) protein of SARS-CoV-2. In this study, a meta-analysis was performed to ensure the genomic variability and stability of the SARS-CoV-2 RdRp protein. The molecular docking of natural and synthetic TP compounds to RdRp and molecular dynamic (MD) simulations were performed to analyse the dynamic behaviour of TP compounds at the active site of the RdRp protein. TP compounds were also docked against other non-structural proteins (NSP1, NSP2, NSP3, NSP5, NSP8, NSP13, and NSP15) of SARS-CoV-2. Furthermore, the inhibition potential of TP compounds was compared with Remdesivir and Favipiravir drugs as a positive control. Additionally, TP compounds were analysed for inhibitory activity against SARS-CoV RdRp protein. This study demonstrates that TP analogues (monomethylated triazolopyrimidine and essramycin) represent potential lead molecules for designing an effective inhibitor to control viral replication. Furthermore, in vitro and in vivo studies will strengthen the use of these inhibitors as suitable drug candidates against SARS-CoV-2.     

Appraisal of the Antioxidant Activity,Polyphenolic Content,and Characterization of Selected Himalayan Herbs: Anti-Proliferative Potential in HepG2 Cells

Natural antioxidants derived from plants have played a vital role in preventing a wide range of human chronic conditions and provide novel bioactive leads for investigators in pharmacotherapy discovery. This work was designed to examine the ethnopharmacological role of Urtica dioica (UD), Capsella bursa-pastoris (CBP), and Inula racemosa (IR). The total phenolic and flavonoid contents (TPC and TFC) were illustrated through colorimetric assays, while the antioxidant activity was investigated through DPPH and ABTS assays. The evaluation of phytochemicals by FT-IR of UD and CBP revealed high contents of aliphatic amines, while IR showed a major peak for ketones. The antioxidant activity, TPC and TFC were highest in the ethanol extract of UD, followed by CBP, and IR showed the lowest activity. All of the extracts revealed significant antioxidant capacities along a dosage gradient. Through a HPLC analysis at a wavelength of 280 nm, UD leaves demonstrated an intense peak of quercetin, and the peak for rutin was less intense. CBP (whole plant), instead, demonstrated a major yield of rutin, and a peak for quercetin was not observed in CBP. IR (rhizomes) showed both quercetin and rutin. All of the extracts were significantly cytotoxic to HepG2 cells after 48 h with the trend IR > UD > CBP. The outcomes of this study may be effective in the selection of specific plants as realistic sources of the bioactive components that might be useful in the nutraceutical progression and other biomedical efficacies.     

In Vivo Anticancer Evaluation of 6b,a Non-Covalent Imidazo[1,2-a]quinoxaline-Based Epidermal Growth Factor Receptor Inhibitor against Human Xenograft Tumor in Nude Mice

Tyrosine kinase inhibitors are validated therapeutic agents against EGFR-mutated non-small cell lung cancer (NSCLC). However, the associated critical side effects of these agents are inevitable, demanding more specific and efficient targeting agents. Recently, we have developed and reported a non-covalent imidazo[1,2-a]quinoxaline-based EGFR inhibitor (6b), which showed promising inhibitory activity against the gefitinib-resistant H1975(L858R/T790M) lung cancer cell line. In the present study, we further explored the 6b compound in vivo by employing the A549-induced xenograft model in nude mice. The results indicate that the administration of the 6b compound significantly abolished the growth of the tumor in the A549 xenograft nude mice. Whereas the control mice bearing tumors displayed a declining trend in the survival curve, treatment with the 6b compound improved the survival profile of mice. Moreover, the histological examination showed the cancer cell cytotoxicity of the 6b compound was characterized by cytoplasmic destruction observed in the stained section of the tumor tissues of treated mice. The immunoblotting and qPCR results further signified that 6b inhibited EGFR in tissue samples and consequently altered the downstream pathways mediated by EGFR, leading to a reduction in cancer growth. Therefore, the in vivo findings were in corroboration with the in vitro results, suggesting that 6b possessed potential anticancer activity against EGFR-dependent lung cancer. 6b also exhibited good stability in human and mouse liver microsomes.