Synergism of low energy microwave irradiation and solid–liquid phase transfer catalysis for selective alkylation of phenols to phenolic ethers

A 100% selectivity with an order of magnitude rate enhancement is obtained in the synthesis of phenolic ethers when synergistic combination of solid–liquid phase transfer catalysis and low energy microwave irradiation (MISL‐PTC) is employed. As against conventional microwave heating with 600 W power input, the current work demonstrates that a low input of 40 W leads to remarkable enhancement in rates without any destruction of the catalyst

Fundamental analysis of microwave irradiated liquid–liquid phase transfer catalysis (MILL-PTC): simultaneous measurement of rate and exchange equilibrium constants in selective O-alkylation of p-tert-butylphenol with benzyl chloride

Fundamentals of low power microwave irradiated liquid–liquid phase transfer catalysis (MILL-PTC) have been brought out in enhancements in the rates of alkylation of p-tert-butylphenol with benzyl chloride and selectivity towards O-alkylated product. Further, a method was proposed for measuring simultaneously the reaction rate constant and anion exchange equilibrium constant from the same set of data. The reaction was studied with a variety of phase transfer catalysts using conventional heating (CH) as well as low power (40 W) microwave irradiation (MW). The O-alkylated product 1-(1,1-dimethylethyl)-4-phenylmethoxybenzene was selectively formed with tetra-n-butylammonium bromide (TBAB) as the catalyst under both CH and MW conditions. The rates of PTC reaction were greatly accelerated under MW. The activation energy of the reaction under CH and MW was nearly the same but the pre-exponential factor in the Arrhenius equation was increased by orders of magnitude under MW. The Gibbs free energy calculated for the exchange reactions suggested that the entropy of MILL-PTC reaction was greater than that of conventionally heated liquid–liquid PTC reaction

Novelties of microwave irradiated solid–liquid phase transfer catalysis (MISL-PTC) in synthesis of 2′-benzyloxyacetophenone

2′-Benzyloxyacetophenone is an important pharmaceutical intermediate for the manufacture of drugs used as diuretics, antihypertensive, platelet, antiaggregant, lipoxygenase, analgesics and prostaglandin, and for treatment of metabolic disorders. Microwave irradiation has been widely used for the rapid synthesis of a variety of compounds. In the current work, for the first time, novelties of low power microwave irradiated solid–liquid phase transfer catalysis, named as MISL-PTC, has been brought out in enhancements of the rates of selective O-alkylation of sodium salt of o-hydroxyacetophenone (OHAP) with benzyl chloride by using tetra-n-butylammonium bromide as a catalyst. The advantages of solid–liquid (S–L) PTC are that the reaction is conducted at controllable temperatures, the rates of reaction are increased by orders of magnitude and the reaction is 100% selective at 80 °C, in comparison with the liquid–liquid (L–L) PTC which is slow and produces by-products. The microwave irradiation further enhances the rates of reaction. The system elegantly forms a synergistic combination of S–L PTC and microwave irradiation. The mechanism based on homogeneous solubilization of solid resulting in the formation of an active ion pair with the nucleophile was found to prevail in the system. A new theoretical analysis is presented to determine both the rate constant and equilibrium constant from the same set of data. The reaction is intrinsically kinetically controlled. The Gibbs free energy for solid dissolution with anion exchange reaction could be also evaluated

Intensification and selectivities in complex multiphase reactions: insight into the selectivity of liquid−liquid phase-transfer-catalyzed O-alkylation of p-methoxyphenol with allyl bromide

Studies in the preparation of aromatic ethers have proven to be quite attractive because of the extensive use of these compounds in the dyestuff, perfume, flavor, agriculture, and pharmaceutical industries. The novelties of phase-transfer-catalyzed alkylation of p-methoxyphenol with allyl bromide were studied in detail in a biphasic system with tetrabutylammonium bromide (TBAB) as the catalyst, and the selectivity of O- versus C-alkylation was compared. The effects of various parameters were studied systematically to understand the conversion patterns; product distribution; and selectivity of the desired product, 1-methoxy-4-(2-propenyloxy)benzene, which is an important perfumery compound. A mechanistic model has been proposed on the basis of the theory of mass transfer with chemical reaction in two liquid phases. The desired product is produced by the O-alkylation reaction between the quaternary 4-methoxyphenoxide and allyl bromide, which takes place instantaneously at a reaction plane in the organic film next to liquid−liquid interface, conforms to the so-called regime 4, and is an example of normal liquid−liquid phase-transfer catalysis (L−L PTC). The isomerization of the desired product to give the first byproduct, the C-alkylated derivative 4-methoxy-2-(2-propenyl)phenol, takes place in the aqueous film by a fast pseudo-first-order reaction (regime 3) and is an example of so-called inverse L−L PTC. This byproduct also has fragrance value. The second byproduct, 1-allyloxy-2-allyl-4-methoxybenzene, is formed by a slow reaction between 4-methoxy-2-(2-propenyl)phenol and allyl bromide in the bulk organic phase and conforms to the so-called regime 1. A 100% selectivity of the desired product is obtained when a stoichiometrically deficient quantity of the base is used at 30 °C. This system is a unique example of mass transfer with complex chemical reactions. It has provided insight into a practical problem with academic excitement, and it also happens to be the first reported case of a PTC reaction in which both normal L−L PTC and inverse PTC are at play

Organ Involvement in COVID-19: A Molecular Investigation of Autopsied Patients

Precise reasons for severe manifestation of SARS-CoV-2 remain unanswered, and efforts have been focused on respiratory system management. Demonstration of unequivocal presence of SARS-CoV-2 in vital body organs by cadaver autopsy was the only way to prove multi-organ involvement. Hence, the primary objective of the study was to determine presence of the SARS-CoV-2 in various organs of patients succumbing to SARS-CoV-2 infection. A total of 246 samples from different organs of 21 patients who died due to severe COVID-19 illness were investigated by qRT-PCR, and SARS-CoV-2 was detected in 181 (73.57%) samples and highest positivity of SARS-CoV-2 being (expectedly) found in nasopharynx (90.4%) followed by bilateral lungs (87.30%), peritoneal fluid (80%), pancreas (72.72%), bilateral kidneys (68.42%), liver (65%) and even in brain (47.2%). The deceased patients were categorized to three subgroups based upon the extent of organs in which SARS-CoV-2 was detected by qRT-PCR (high intensity ≥80%, intermediate intensity = 65–80% and low intensity ≤65% organs involvement). It was conclusively established that SARS-CoV-2 has the property of invasion beyond lungs and even crosses the blood–brain barrier, resulting in multi-system disease; this is probably the reason behind cytokine storm, though it is not clear whether organ damage is due to direct injury caused by the virus or result of inflammatory assault. Significant inverse correlation was found between the Ct value of lung samples and number of organs involved, implying that higher viral load in lungs is directly proportionate to involvement of extrapulmonary organs and patients with higher viral load in respiratory secretions should be monitored more closely for any warning signs and the treatment strategies should also address involvement of other organs for better outcome, because lungs, though the primary site of infection, are not the only organ system responsible for pathogenesis of systemic illness

Abstracts of AICTE Sponsored International Conference on Post-COVID Symptoms and Complications in Health

This book presents the selected abstracts of the International Conference on Post-COVID Symptoms and Complications in Health, hosted from the 28th to 29th of April 2022 in virtual mode by the LR Institute of Pharmacy, Solan (H.P.)-173223 in Collaboration with AICTE, New Delhi. This conference focuses on the implications of long-term symptoms on public health, ways to mitigate these complications, improve understanding of the disease process in COVID-19 patients, use of computational methods and artificial intelligence in predicting complications, and the role of various drug delivery systems in combating the complications. Conference Title:  International Conference on Post-COVID Symptoms and Complications in HealthConference Sponsor: AICTE, New Delhi.Conference Date: 28-29 April 2022Conference Location: OnlineConference Organizer: LR Institute of Pharmacy, Solan (H.P.)-173223

Abstracts of AICTE Sponsored International Conference on Post-COVID Symptoms and Complications in Health

This book presents the selected abstracts of the International Conference on Post-COVID Symptoms and Complications in Health, hosted from the 28th to 29th of April 2022 in virtual mode by the LR Institute of Pharmacy, Solan (H.P.)-173223 in Collaboration with AICTE, New Delhi. This conference focuses on the implications of long-term symptoms on public health, ways to mitigate these complications, improve understanding of the disease process in COVID-19 patients, use of computational methods and artificial intelligence in predicting complications, and the role of various drug delivery systems in combating the complications. Conference Title:  International Conference on Post-COVID Symptoms and Complications in HealthConference Sponsor: AICTE, New Delhi.Conference Date: 28-29 April 2022Conference Location: OnlineConference Organizer: LR Institute of Pharmacy, Solan (H.P.)-173223

Abstracts of Scientifica 2022

This book contains the abstracts of the papers presented at Scientifica 2022, Organized by the Sancheti Institute College of Physiotherapy, Pune, Maharashtra, India, held on 12–13 March 2022. This conference helps bring researchers together across the globe on one platform to help benefit the young researchers. There were six invited talks from different fields of Physiotherapy and seven panel discussions including over thirty speakers across the globe which made the conference interesting due to the diversity of topics covered during the conference. Conference Title:  Scientifica 2022Conference Date: 12–13 March 2022Conference Location: Sancheti Institute College of PhysiotherapyConference Organizer: Sancheti Institute College of Physiotherapy, Pune, Maharashtra, Indi