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Shiv Nadar University

(SoNS) School of Natural Sciences

This paper describes an efficient, sustainable, one-step procedure for synthesizing substituted phenazines and phenoxazinones from commercially available ortho-substituted aromatic amines with very good yield (≥80%) in water. The procedure uses eosin Y (EY) as a photoredox catalyst at room temperature (RT). The highly reactive o-quinone-diimine or o-quinone-imine intermediate was characterized by the HR-MS technique. © 2021 American Chemical Society.

World University root node

Chemistry

Organic Letters

Visible-light-mediated synthesis of substituted phenazine and phenoxazinone using eosin y as a photoredox catalyst

The eight membered ring system with one sulfur (S) atom was reviewed in the CHEC-III (2008) 1 and the articles were covered until the beginning of 2007. This ring system is difficult to synthesize and there are only handful of literatures between 2007 and 2020 describing their chemistry. Herein we will discuss synthesis of benzene fused eight membered sulfur containing ring system and bridged eight membered sulfur containing rings along with reactions of eight membered sulfur containing rings for synthesis of cyclic alkynes, their cycloaddition reactions and synthesis of chiral thiofulvenes. Additionally, we will also report a kinetic investigation, NMR study and ring strain/reactivity involving such ring systems. © 2022 Elsevier Ltd. All rights reserved.

Comprehensive Heterocyclic Chemistry IV

Eight-Membered Rings With One Sulfur Atom

Low-power, flexible, and properly encapsulated integrated circuits are the basic requirements of the solution-processed printed and wearable electronic prototypes for various emerging applications including display circuits, sensors, and radio-frequency identification tags. The organic field-effect transistor is one of the important types of devices used in such prototypes and its industrial applicability is essential for the printed electronics technology. The performance deterioration upon encapsulated through the thick layer of air-stable dielectric material such as amorphous fluoropolymer [CYTOP] - must be compensated by device engineering. In this work, we used furan and thiophene flanked diketopyrrolopyrrole donor-acceptor conjugated polymers namely PDPPF-DTT and PDPPT-DTT, and its comparative study was performed using Cytop as a dielectric material. The work advances interface engineering towards the single-gate and dual-gate organic transistors. Dual-gate transistors performance modulation using Cytop dielectric opens new research avenues towards stability enhancement of such transistors for real-world applications. © 2021 The Author(s). Published by IOP Publishing Ltd.

Physics

Materials Research Express

Single and dual-gate organic field-effect transistors based on diketopyrrolopyrrole-diethienothiophene polymers: Performance modulation via dielectric interfaces

Anew wavelength-resolved thermo luminescence (TL) cum optically stimulated luminescence (OSL) reader system has been designed and developed. This reader system uses the compact Seya-Namioka optical layout based monochromator, PMT, and resistive heating method to acquire TL glow curve emissions spectrum. The phosphor samples heated from room temperature to 400 °C, either linearly with a programmable heating rate of 0.01 to 30Ks-1 or alternative constant step temperature profiles. The TL glow curve emission spectrum has been resolved by rotating the grating attached to a monochromator covering the wavelength from 200 to 900 nm. The wavelength scanning is linear with respect to time and the scan rate can be selected from 0.1 to 8 nms-1. A broad spectral response of the PMTdetection module has been used to record the emitted TL spectrum. The blue (465nm) reference LED light source is provided for a spectrum calibration of the monochromator. The isometric 3D TL emission spectra of LiCaAlF6:Eu,Y, α-Al2O3:C, and CaSO4:Dy have been successfully recorded using this reader system. In order to record the OSL emission spectrum, 470nmblue LEDs have been provided as a separate stimulation module. ©2021 IOP Publishing Ltd.

Engineering Research Express

Development of wavelength-resolved 3D-inegrated TL and OSL reader system

We simulate a system of coupled kicked tops to generate random density matrices distributed according to the Bures-Hall measure, which has an important role in quantum information theory. We study the effects of stochasticity and coupling parameters of the coupled-kicked-top system on the behavior of the associated bipartite pure state, eigenvalues and eigenvectors of the reduced state, and average entropies. For strongly chaotic phase space and adequate coupling between the constituting tops (subsystems), we find that the results of simulation agree with analytical results of random matrix theory. We also examine local fluctuation properties of the Bures-Hall eigenvalues using the distribution of nearest-neighbor spacing ratios. In the limit of high-dimensional density matrices, the empirical ratio distribution is found to approach the Wigner-surmise-like result for the Gaussian unitary ensemble. Additionally, we present some closed-form results for the Bures-Hall spectral density and corresponding moments using Meijer G functions. © 2021 American Physical Society.

Physical Review A

Generation of Bures-Hall mixed states using coupled kicked tops

Pyrrole and indole derivatives are functionalizedviaa green initiative with the dimethyl malonate derived phenyl iodonium ylide4ain the presence of a blue LEDviaC-H functionalization of the respective heterocycles in methanol to generate the desired compounds5-7in moderate to good yields. Control experiments provide insight into the probable reaction mechanism. Finally, the strategy is successfully applied in the generation of azepino[4,5-b]indole12a/b. © The Royal Society of Chemistry 2021.

Fulltext

Organic and Biomolecular Chemistry

A sustainable C-H functionalization of indoles, pyrroles and furans under a blue LED with iodonium ylides

Glycosyltransferases (GTs) catalyze the formation of glycosidic bonds in carbohydrates and glycoconjugates, with various outcomes depending not only on the acceptor molecules they bind but also on the type of glycosidic bond they form (C-O, C-N, C-S, or C-C). Here we show that the glucosyltransferase UGT1 from the indigo plant Polygonum tinctorium catalyzes either N-, O-, or S-glycosylation with similar rates. We solve the structure of the enzyme in complex with its donor and acceptor substrates and elucidate the molecular basis of N-, O-, and S-specificities using experimental mutagenesis and QM/MM simulations, revealing distinct mechanisms for N-, O-, and S-glycosylation. We also show that the active site can be engineered to increase or favor one of the three glycosylation activities over another. These results will foster the design of more active and specific enzyme variants for production of glycosides. ©

ACS Catalysis

O-/ N-/ S-Specificity in Glycosyltransferase Catalysis: From Mechanistic Understanding to Engineering

Climate changes and environmental stresses have a consequential association with crop plant growth and yield, meaning it is necessary to cultivate crops that have tolerance toward the changing climate and environmental disturbances such as water stress, temperature fluctuation, and salt toxicity. Recent studies have shown that trans-acting regulatory elements, including microRNAs (miRNAs) and transcription factors (TFs), are emerging as promising tools for engineering naive improved crop varieties with tolerance for multiple environmental stresses and enhanced quality as well as yield. However, the interwoven complex regulatory function of TFs and miRNAs at transcriptional and post-transcriptional levels is unexplored in Oryza sativa. To this end, we have constructed a multiple abiotic stress responsive TF-miRNA-gene regulatory network for O. sativa using a transcriptome and degradome sequencing data meta-analysis approach. The theoretical network approach has shown the networks to be dense, scale-free, and small-world, which makes the network stable. They are also invariant to scale change where an efficient, quick transmission of biological signals occurs within the network on extrinsic hindrance. The analysis also deciphered the existence of communities (cluster of TF, miRNA, and genes) working together to help plants in acclimatizing to multiple stresses. It highlighted that genes, TFs, and miRNAs shared by multiple stress conditions that work as hubs or bottlenecks for signal propagation, for example, during the interaction between stress-responsive genes (TFs/miRNAs/other genes) and genes involved in floral development pathways under multiple environmental stresses. This study further highlights how the fine-tuning feedback mechanism works for balancing stress tolerance and how timely flowering enable crops to survive in adverse conditions. This study developed the abiotic stress-responsive regulatory network, APRegNet database (http://lms.snu.edu.in/APRegNet), which may help researchers studying the roles of miRNAs and TFs. Furthermore, it advances current understanding of multiple abiotic stress tolerance mechanisms. © Copyright © 2021 Sharma, Upadhyay, Bhattacharya and Singh.

Mathematics

Life Sciences

Frontiers in Genetics

Abiotic Stress-Responsive miRNA and Transcription Factor-Mediated Gene Regulatory Network in Oryza sativa: Construction and Structural Measure Study

Chemotherapy is a general treatment procedure for cancer. The diversity in cancer incidence and the failure of therapy due to chemoresistance lead to increased cancer-related deaths. Therefore, new drugs with fewer secondary complications targeting diverse pathways are the need of the hour. Geranyl isovalerate (GIV), one of the active ingredients of ethyl acetate fraction of Argyreia nervosa is routinely used as a food flavoring agent. In this study, we found that GIV also exhibits anticancer activity when tested against the HCT116 cell line. It influenced the viability of the cells in a dose- and time-dependent manner. We examined whether GIV could induce oxidative stress and affect the mitochondrial membrane potential, thereby leading to apoptosis induction. Moreover, GIV could suppress the expression of antiapoptotic genes, such as BCl2 and PARP, and induce the expression of proapoptotic genes, such as Caspase 3 and 9. This is the first study demonstrating the anticancer activity of GIV and providing evidence for its mechanism of action. In conclusion, this study proposes GIV as a potential lead or supplementary molecule in treating and preventing colorectal cancer (CRC). Based on our findings, we conclude that GIV may be a viable lead or supplementary molecule for treating and preventing CRC. © Copyright © 2021 Rasool, Sharma, Anand, Magani and Tantravahi.

Frontiers in Pharmacology

Evaluation of the Anticancer Properties of Geranyl Isovalerate, an Active Ingredient of Argyreia nervosa Extract in Colorectal Cancer Cells

Background: Despite numerous efforts to eradicate the disease, malaria continues to remain one of the most dangerous infectious diseases plaguing the world. In the absence of any effective vaccines and with emerging drug resistance in the parasite against the majority of anti-malarial drugs, the search for new drugs is urgently needed for effective malaria treatment. Methods: The goal of the present study was to examine the compound library, based on indoles generated through diversity-oriented synthesis belonging to four different architecture, i.e., 1-aryltetrahydro/dihydro-β-carbolines and piperidine/pyrrolidine-fused indole derivatives, for their in vitro anti-plasmodial activity. Trifluoroacetic acid catalyzed transformation involving tryptamine and various aldehydes/ketones provided the library. Results: Among all the compounds screened, 1-aryltetrahydro-β-carbolines 2 and 3 displayed significant anti-plasmodial activity against both the artemisinin-sensitive and artemisinin-resistant strain of Plasmodium falciparum. It was observed that these compounds inhibited the overall parasite growth in intra-erythrocytic developmental cycle (IDC) via reactive oxygen species-mediated parasitic death and thus could be potential anti-malarial compounds. Conclusion: Overall the compounds 2 and 3 identified in this study shows promising anti-plasmodial activity that can kill both artemisinin-sensitive and artemisinin-resistant strains of P. falciparum. © 2021, The Author(s).