Preparation, structure and reactivity of some new types of stabilised phosphorus ylides

Sixteen examples of the previously unknown β,γ,β'-trioxo phosphorus ylides have been prepared and fully characterised. Upon flash vacuum pyrolysis (FVP) these undergo clean loss of Ph₃PO selectively across the central position to afford diacylalkynes in most cases. The pyrolysis results are discussed in the light of the fully assigned ¹³C NMR spectra presented and in particular the values of ²jp-C(C=O). Six examples of the higher homologues, the β,γ,β,γ-tetraoxo ylides have also been prepared and are found, quite unexpectedly, to give poor results upon FVP but to undergo moderately successful Ph₃PO extrusion to afford trioxoalkynes using conventional pyrolysis. The known β,γ-dioxophosphonium salts required as precursors to these have been characterised by NMR for the first time and are shown to exist predominantly as mixtures of E and Z enol forms in solution. By reaction with oxalyl chloride, a range of higher polyoxo bis ylides has been obtained, including three examples of hexaoxo bis ylides which are remarkable in containing an acyclic series of eight contiguous C=X centres. The ¹³C NMR spectra for the oxalyl bis ylides are interesting due to the pattern of coupling observed to both phosphorus atoms. These compounds do not in general give any useful results from FVP presumably due to the thermal instability of the expected products. The reactivity of dioxo, trioxo, tetraoxo and oxalyl bis ylides towards a variety of oxidants has been examined and has given promising preliminary results for the formation of vicinal polycarbonyl compounds. Vicinal triones and tetraones are readily obtained and some evidence for a pentaone was obtained in one case. All the products readily form the molecular hydrates with geminal diol structures and these have been characterised spectroscopically. Reaction of the various ylide types with NO₂ has been examined and a range of different processes is observed including formation of nitriles accompanied in one case by ring nitration of a phenyl group. A total of twenty five β-aminoacyl ylides derived from N-alkoxycarbonyl protected amino acids have been prepared using a carbodiimide coupling method and have been fully characterised. Upon FVP at 600°C these readily lose Ph₃PO to afford protected acetylenic amino acid derivatives and twelve examples of these valuable chiral compounds have been obtained in moderate yield. By standard reactions these products have been transformed into simple chiral analogues of the important neurotransmitter GABA in four cases. Removal of the N-protecting group in the amino acid derived ylides results in a change in pyrolysis behaviour: ethanol is eliminated rather than Ph₃PO to give novel cyclic stabilised ylides related in structure to the tetramic acids. Finally, samples of one trioxo ylide, one tetraoxo ylide, one tetraoxo bis ylide and one hexaoxo bis ylide have been sent for solid state structure determination by X-ray methods. The results obtained provide ready confirmation of the important contribution of phosphonium enolate forms to the structures of these but give surprising results as regards the conformational preference for syn and anti alignments of the adjacent C=X units along the chain

Greening Chemical Engineering laboratory at Bradford University

YesThis paper highlights the work undertaken to assess the current state of the art of the Chemical Engineering Laboratory at the University of Bradford (UK) in terms of total energy and water usage and sound pollution and to propose an action plan to ‘greening’ the laboratory so that future students are trained in a laboratory where sustainability is the key feature of all learning activities. The project was funded by National Higher Education STEM (Science Technology Engineering and Mathematics) Programme. This review and assessment was carried out by two academic staff and one technical staff member with chemical engineering background.National HE STEM Programm

Multimodal role of amino acids in microbial control and drug development

Amino acids are ubiquitous vital biomolecules found in all kinds of living organisms including those in the microbial world. They are utilised as nutrients and control many biological functions in microorganisms such as cell division, cell wall formation, cell growth and metabolism, intermicrobial communication (quorum sensing), and microbial‐host interactions. Amino acids in the form of enzymes also play a key role in enabling microbes to resist antimicrobial drugs. Antimicrobial resistance (AMR) and microbial biofilms are posing a great threat to the world’s human and animal population and are of prime concern to scientists and medical professionals. Although amino acids play an important role in the development of microbial resistance, they also offer a solution to the very same problem i.e., amino acids have been used to develop antimicrobial peptides as they are highly effective and less prone to microbial resistance. Other important applications of amino acids include their role as anti‐biofilm agents, drug excipients, drug solubility enhancers, and drug adjuvants. This review aims to explore the emerging paradigm of amino acids as potential therapeutic moieties

Staphylococcus aureus biofilm: Morphology, genetics, pathogenesis and treatment strategies

© 2021 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/ijerph18147602Staphylococcus aureus is a nosocomial bacterium causing different infectious diseases, rang-ing from skin and soft tissue infections to more serious and life-threatening infections such as sep-ticaemia. S. aureus forms a complex structure of extracellular polymeric biofilm that provides a fully secured and functional environment for the formation of microcolonies, their sustenance and recol-onization of sessile cells after its dispersal. Staphylococcus aureus biofilm protects the cells against hostile conditions, i.e., changes in temperature, limitations or deprivation of nutrients and dehydra-tion, and, more importantly, protects the cells against antibacterial drugs. Drugs are increasingly becoming partially or fully inactive against S. aureus as they are either less penetrable or totally impenetrable due to the presence of biofilms surrounding the bacterial cells. Other factors, such as evasion of innate host immune system, genome plasticity and adaptability through gene evolution and exchange of genetic material, also contribute to the ineffectiveness of antibacterial drugs. This increasing tolerance to antibiotics has contributed to the emergence and rise of antimicrobial resistance (AMR), a serious problem that has resulted in increased morbidity and mortality of human and animal populations globally, in addition to causing huge financial losses to the global economy. The purpose of this review is to highlight different aspects of S. aureus biofilm formation and its overall architecture, individual biofilm constituents, clinical implications and role in pathogenesis and drug resistance. The review also discusses different techniques used in the qualitative and quantitative investigation of S. aureus biofilm and various strategies that can be employed to inhibit and eradicate S. aureus biofilm.M.I. was funded by Faculty of Science and Engineering, University of Wolverhampton.Published versio

The big green lab project

YesBeverley Lucas and her colleagues give us a big green welcome to the Ecoversity of Bradford In 2005, the Higher Education Funding Council for England (Hefce) stated that ‘the greatest contribution a university can make to sustainable development is through the education of their graduates’. The University of Bradford took up the gauntlet, embedding sustainable development in all areas of its campus whilst also transforming the curriculum across the university to educate for sustainable development. This led to them coining themselves an ecoversity.The authors would like to thank the National HE STEM Programme for funding this project

The value of 2 J P–CO as a diagnostic parameter for the structure and thermal reactivity of carbonyl-stabilised phosphonium ylides

A survey of 20 carbonyl-stabilised phosphonium ylides with recently reported X-ray structures shows a strong correlation between the CP to CO torsion angle and the value of 2JP–CO, with high values being associated with an anti configuration and low with syn. Seven new X-ray structural determinations are reported, several for types of ylide not crystallographically characterised before, and these also conform to this pattern. The value of 2JP–CO is then correlated with whether or not thermal extrusion of Ph3PO occurs to give alkynes for over 200 ylides and an empirical rule developed that the extrusion never occurs for ylides where this value is > 11 Hz. This is used to rationalise the anomalous behaviour of some trioxo ylides and cyclic ylides, two of which afford cycloalkynes, isolated after rearrangement as the isomeric 1,3-dienes. The rule also holds for a family of novel highly fluorinated ylides which afford fluorinated alkynes in good yield upon flash vacuum pyrolysis.EPSRC (U.K.) for a DTA Studentship (Grant No. EP/P505712/1

Synthesis and evaluation of selected benzimidazole derivatives as potential antimicrobial agents

© 2015 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/molecules200815206© 2015 by the authors. A library of 53 benzimidazole derivatives, with substituents at positions 1, 2 and 5, were synthesized and screened against a series of reference strains of bacteria and fungi of medical relevance. The SAR analyses of the most promising results showed that the antimicrobial activity of the compounds depended on the substituents attached to the bicyclic heterocycle. In particular, some compounds displayed antibacterial activity against two methicillin-resistant Staphylococcus aureus (MRSA) strains with minimum inhibitory concentrations (MICs) comparable to the widely-used drug ciprofloxacin. The compounds have some common features; three possess 5-halo substituents; two are derivatives of (S)-2-ethanaminebenzimidazole; and the others are derivatives of one 2-(chloromethyl)-1Hbenzo[ d]imidazole and (1H-benzo[d]imidazol-2-yl)methanethiol. The results from the antifungal screening were also very interesting: 23 compounds exhibited potent fungicidal activity against the selected fungal strains. They displayed equivalent or greater potency in their MIC values than amphotericin B. The 5-halobenzimidazole derivatives could be considered promising broad-spectrum antimicrobial candidates that deserve further study for potential therapeutic applications.Published versio

Synthesis and characterisation of novel nopyl-derived phosphonium ionic liquids

A series of novel nopyl-derived chiral phosphonium ionic liquids have been successfully synthesised and characterised. Analysis of each novel ionic liquid was conducted in order to confirm structure, purity and thermal stability

The Big Read Collaboration between Kingston University, the University of Wolverhampton, Edge Hill University, and the University of the West of Scotland, 2018–2019

This paper outlines the experience of four universities that collaborated on a pre-arrival shared reading project, the Big Read, in 2018/2019. They did so primarily to promote student engagement and retention and also to ease the transition into higher education, particularly for first-generation students, to promote staff connectedness, and to provide a USP (unique selling point) for their institution. The paper covers all the associated processes, from isolating the respective aims of the collaborators to the choosing and sharing of a single agreed title. In analysing the outcomes, recommendations are made for future cross-institutional projects of this kind

Synthesis, structure and pyrolysis of stabilised phosphonium ylides containing saturated oxygen heterocycles

yesA range of twelve stabilised phosphonium ylides containing tetrahydrofuran, tetrahydropyran or 2,2- dimethyl-1,3-dioxolane rings have been prepared and fully characterised, including one X-ray structure determination of each type. The X-ray structures confirm the PvC and CvO functions to be syn and all the compounds undergo thermal extrusion of Ph3PO to give the corresponding alkynes. In some cases there is also competing loss of Ph3P to give different carbene-derived products and evidence has been obtained for the generation of 2-phenyloxete in this way. Raising the pyrolysis temperature leads in several cases to new secondary reactions of the alkyne products involving a sequence of alkyne to vinylidene isomerisation, intramolecular CH insertion, and retro Diels Alder reaction