Chem Commun (Camb)
September 2024
The visible light-promoted -alkenylation of phenols and naphthols with terminal alkynes is achieved using 2,4,6-tris(4-fluorophenyl)pyrylium tetrafluoroborate (T(-F)PPT) as a photocatalyst at room temperature without the need of any external ligand or additive. Apart from its excellent functional group tolerance, the protocol described herein represents an appealing alternative strategy to classical transition-metal catalysed hydroarylation reactions. Mechanistic investigations revealed that the reaction involves a radical pathway.
View Article and Find Full Text PDFIn the contemporary practice of palladium catalysis, a molecular understanding of the role of vital additives used in such reactions continues to remain rather vague. Herein, we disclose an intriguing and a potentially general role for one of the most commonly used silver salt additives, discovered through rigorous computational investigations on four diverse Pd-catalyzed C-H bond activation reactions involving sp aryl C-H bonds. The catalytic pathways of different reactions such as phosphorylation, arylation, alkynylation, and oxidative cycloaddition are analyzed, with and without the explicit inclusion of the silver additive in the respective transition states and intermediates.
View Article and Find Full Text PDFShiga toxin-producing Escherichia coli (STEC), Enteropathogenic E. coli (EPEC), and Enterotoxigenic E. coli (ETEC) make up an important group of pathogens causing major animal and public health concerns worldwide.
View Article and Find Full Text PDFEpidemiol Infect
September 2018
Occurrence of Salmonella spp. in captive wild animal species in India is largely unknown. The purpose of this study was to determine the occurrence of different Salmonella serotypes, antimicrobial resistance patterns and genotypic relatedness of recovered isolates.
View Article and Find Full Text PDFA comprehensive mechanistic study on the title reaction by using DFT(B3LYP-D3) computational method is reported. Explicit consideration of mono- (m-xylylic) and dicarboxylic acid (phthalic) in the key transition states reveals active participation of the carboxylic acid, beginning with the generation of a monomeric Rh(I) active catalyst and in the ensuing catalytic steps. In the early catalytic event, uptake of alkyne is predicted to take place only after the oxidative addition of the Rh(I) active catalyst to the carboxylic acid.
View Article and Find Full Text PDFThe diversity of toxin-genotypes of C. perfringens in neonatal calves was determined in this study. A total of 682 fresh faecal samples comprising 559 healthy and 123 diarrheic neonatal calves (cattle and buffalo) were collected from various farms in Northern India.
View Article and Find Full Text PDFCampylobacteriosis is an important zoonotic disease and the prevalence of Campylobacter is largely unknown in the wildlife of India. A total of 370 samples, comprising of 314 fresh faecal samples from apparently healthy captive wild animals and birds, 30 stool swabs from animal care takers and 26 samples of the animals' food and water were collected from G. B.
View Article and Find Full Text PDFLow pathogenic avian influenza virus (LPAIV) exhibits an ecological climax with the aquatic ecosystem. The most widely prevalent subtype of LPAIV is H9N2. Wild aquatic birds being the natural reservoirs and ducks, the "Trojan horses" for Avian Influenza Virus (AIV), can contaminate the natural water bodies inhabited by them.
View Article and Find Full Text PDFThe prevalence of Clostridium perfringens in captive wildlife in India has not been reported. The objective of the study was to determine the fecal prevalence of C. perfringens in captive wildlife in India.
View Article and Find Full Text PDFMetallic salts as well as protic additives are widely employed in transition metal catalyzed C-H bond functionalization reactions to improve the efficiency of catalytic protocols. In one such example, ZnCl and pivalic acid are used as additives in a palladium catalyzed synthesis of isoxazolone from a readily available benzohydroxamic acid under one pot conditions. In this article, we present some important mechanistic insights into the role of ZnCl and pivalic acid, gained by using density functional theory (M06) computations.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
January 2010
Complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) with a novel heterocyclic azo derivative, formed by coupling diazotized 2-amino-3-carbethoxy-4,5-dimethylthiophene with acetylacetone were synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, UV-vis, IR, (1)H NMR and EPR spectral data. Spectral studies revealed that the ligand existed in an internally hydrogen bonded azo-enol form rather than the keto-hydrazone form and coordinated to the metal ion in a tridentate fashion. Analytical data revealed that all the complexes exhibited 1:1 metal-ligand ratio.
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