Amrita Srivastava

Bio: Amrita Srivastava is an academic researcher from University of Lucknow. The author has contributed to research in topics: Sodium periodate & Reactivity (chemistry). The author has an hindex of 3, co-authored 16 publications receiving 24 citations.

Sodium Periodate as a Selective Oxidant for Diclofenac Sodium in Alkaline Medium: A Quantum Chemical Approach

Abstract: Diclofenac sodium is a well known anti-inflammatory drug. It has also been proclaimed to exhibit adverse effects on aquatic animals through sewage and waste water treatment plants. Kinetic and mechanistic studies of the novel oxidation of diclofenac sodium (DFS) by sodium periodate were discussed with an emphasis on structure and reactivity by using kinetic and computational approach. The proposed work had been studied in alkaline medium at 303 K and at a constant ionic strength of 0.60 mol.dm−3. Formation of [2-(2,6-dicloro-phynylamino)-phenyl]-methanol as the oxidation product of DFS is confirmed with the help of structure elucidation. The active species of catalyst, oxidant and oxidation products were recognized by UV and IR spectral studies. Proton inventory studies in H2O−D2O mixtures had been shown the involvement of a single exchangeable proton of OH− ion in the transition state. All quantum chemical calculations were executed at level of density functional theory (DFT) with B3LYP function using 6-31G (d,p) basis atomic set for the validation of structure, reaction and mechanism. Molecular orbital energies, nonlinear optical properties, bond length, bond angles, reactivity, electrophilic and nucleophilic regions were delineated. Influence of various reactants on rate of chemical reaction were also ascertained and elucidated spectro-photometrically. Activation parameters have been assessed using Arrhenius-Eyring plots. A suitable mechanism consistent with observed kinetic results had been implicated and rate law deduced. Copyright © 2020 BCREC Group. All rights reserved

Kinetic, Mechanistic, and Thermodynamic Studies for Oxidation of L-Alanine by Alkaline Sodium Periodate in Presence of Os(VIII) in its Nano Concentration Range as Homogenous Catalyst

Abstract: The kinetics and mechanism of homogenously Os(VIII) catalysed oxidation of L-alanine (L-ala) by alkaline sodium periodate in temperature range 30 to 45°C have been studied. The involvement of free radicals was observed in the reactions. The oxidation products were acetaldehyde and IO 3 - , identified by spot test and spectroscopic studies. The stoichiometry between [L-ala]: IO 4 - is 1:2. The reaction show negligible effect of mercuric acetate and ionic strength of medium. The experimental results show first order in oxidant [NaIO 4 ] and negative effect of [OH - ]. The order in [Os(VIII)] as well as L-alanine was unity. A mechanism involving the formation of complex between L-alanine and Os(VIII) was proposed. The reaction constants concerned in the different steps of mechanism were calculated at different temperature. The activation parameters for the slow step of mechanism were computed and discussed. The thermodynamic quantities were also calculated for the reaction. Copyright © 2018 BCREC Group. All rights reserved Received: 11 st October 2017; Revised: 11 st February 2018; Accepted: 18 th February 2018; Available online: 11 st June 2018; Published regularly: 1 st August 2018 How to Cite : Gupta, M., Srivastava, A., Srivastava, S. (2018). Kinetic, Mechanistic, and Thermodynamic Studies for Oxidation of L-Alanine by Alkaline Sodium Periodate in Presence of Os(VIII) in its Nano Concentration Range as Homogenous Catalyst. Bulletin of Chemical Reaction Engineering & Catalysi s, 13 (2): 355-364 (doi:10.9767/bcrec.13.2.1583.355-364)

Intermittent Food Absence Motivates Reallocation of Locomotion and Feeding in Spotted Munia (Lonchura punctulata)

Abstract: Background: Daily feeding and locomotion are interrelated behaviours. The time spent in feeding and rate of food intake depends on food availability. In low food condition, the birds would show intense movement (locomotion) for a longer time throughout the day however during abundant food supply they may chose higher activity and food intake in the morning and evening only. In the present study we hypothesized that in Spotted Munia (Lonchura punctulata), intermittent food availability during day would reallocate their interrelated behaviors, the feeding (food intake) and locomotor activity patterns. Methods: Two groups of birds (N = 6 each) were kept individually in activity cages under 12L:12D. Group 1 (Control; C) had ad libitum food but group 2 (Treatment; T) had food for 6 hours only (2 h presence followed by 2 h absence; 2P:2A) during 12 hour light period. In the first week, group 2 received food with ‘lights on’ (TI; ZT 0–2, 4–6 and 8–10; where ZT 0= zeitgeber time 0, time of lights ON). In the following week, the food was given 2 hours after ‘lights on’ (TII; ZT 2–4, 6–8, 10–12). The food intake and locomotor activity under each condition were observed. Results: The results showed that locomotor activity was induced during food deprivation and suppressed during food availability. Also the food deprivation led to increased food intake. Conclusion: Our results suggest that intermittent food availability/ deprivation reallocates the locomotor activity and food intake in Spotted Munia.

Chemical Insights Into the Synthetic Chemistry of Quinazolines: Recent Advances.

Abstract: In medicinal chemistry, one of the most significant heterocyclic compounds are quinazolines, possessing broad range of biological properties such as anti-bacterial, anti-fungal, anti-HIV, anti-cancer, anti-inflammatory, and analgesic potencies. Owing to its numerous potential applications, in the past two decades, there is an increase in the importance of designing novel quinazolines, exploring promising routes to synthesize quinazolines, investigating different properties of quinazolines, and seeking for potential applications of quinazolines. The present review article describes synthesis of quinazolines via eco-friendly, mild, atom-efficient, multi-component synthetic strategies reported in the literature. The discussion is divided into different parts as per the key methods involved in the formation of quinazoline skeletons, aiming to provide readers an effective methodology to a better understanding. Consideration has been taken to cover the most recent references. Expectedly, the review will be advantageous in future research for synthesizing quinazolines and developing more promising synthetic approaches.

Environmental status of groundwater affected by chromite ore processing residue (COPR) dumpsites during pre-monsoon and monsoon seasons.

Abstract: Chromite ore processing residue (COPR) is generated by the roasting of chromite ores for the extraction of chromium. Leaching of carcinogenic hexavalent chromium (Cr(VI)) from COPR dumpsites and contamination of groundwater is a key environmental risk. The objective of the study was to evaluate Cr(VI) contamination in groundwater in the vicinity of three COPR disposal sites in Uttar Pradesh, India, in the pre-monsoon and monsoon seasons. Groundwater samples (n = 57 pre-monsoon, n = 70 monsoon) were taken in 2014 and analyzed for Cr(VI) and relevant hydrochemical parameters. The site-specific ranges of Cr(VI) concentrations in groundwater were <0.005 to 34.8 mg L−1 (Rania), <0.005 to 115 mg L−1 (Chhiwali), and <0.005 to 2.0 mg L−1 (Godhrauli). Maximum levels of Cr(VI) were found close to the COPR dumpsites and significantly exceeded safe drinking water limits (0.05 mg L−1). No significant dependence of Cr(VI) concentration on monsoons was observed.

Microwave-Assisted Synthesis of Quinazolines and Quinazolinones: An Overview.

Abstract: Microwave irradiation (MWI), as a unique, effective, sustainable, more economic, and greener source of energy compared to conventional heating, is applied in different organic transformations to result in the rapid formation of desired compounds due to thermal/kinetic effects. In this review, we try to underscore the applications of microwave irradiation (MWI) in the synthesis of quinazoline and quinazolinone derivatives that have been achieved and reported on in the last two decades.

Seasonally sympatric but allochronic: differential expression of hypothalamic genes in a songbird during gonadal development.

Abstract: Allochrony, the mismatch of reproductive schedules, is one mechanism that can mediate sympatric speciation and diversification. In songbirds, the transition into breeding condition and gonadal growth is regulated by the hypothalamic-pituitary-gonadal (HPG) axis at multiple levels. We investigated whether the difference in reproductive timing between two seasonally sympatric subspecies of dark-eyed juncos (Junco hyemalis) was related to gene expression along the HPG axis. During the sympatric pre-breeding stage, we measured hypothalamic and testicular mRNA expression of candidate genes via qPCR in captive male juncos. For hypothalamic mRNA, we found our earlier breeding subspecies had increased expression of gonadotropin-releasing hormone (GnRH) and decreased expression of androgen receptor, oestrogen receptor alpha and mineralocorticoid receptor (MR). Subspecies did not differ in expression of hypothalamic gonadotropin-inhibitory hormone (GnIH) and glucocorticoid receptor (GR). While our earlier breeding subspecies had higher mRNA expression of testicular GR, subspecies did not differ in testicular luteinizing hormone receptor, follicle-stimulating hormone receptor or MR mRNA expression levels. Our findings indicate increased GnRH production and decreased hypothalamic sensitivity to sex steroid negative feedback as factors promoting differences in the timing of gonadal recrudescence between recently diverged populations. Differential gene expression along the HPG axis may facilitate species diversification under seasonal sympatry.