High-Throughput Kinetic Analysis for Target-Directed Covalent Ligand Discovery.

Cysteine-reactive small molecules are used as chemical probes of biological systems and as medicines. Identifying high-quality covalent ligands requires comprehensive kinetic analysis to distinguish selective binders from pan-reactive compounds. Quantitative irreversible tethering (qIT), a general method for screening cysteine-reactive small molecules based upon the maximization of kinetic selectivity, is described. This method was applied prospectively to discover covalent fragments that target the clinically important cell cycle regulator Cdk2. Crystal structures of the inhibitor complexes validate the approach and guide further optimization. The power of this technique is highlighted by the identification of a Cdk2-selective allosteric (type IV) kinase inhibitor whose novel mode-of-action could be exploited therapeutically

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

Functionalisation of saturated heterocycles at unactivated positions by palladium-catalysed directed C(sp3)–H arylation

Saturated heterocycles are vital components of many biologically active compounds that are central to life, and offer great potential as pharmaceuticals for complex targets. Therefore, synthetic methods to efficiently synthesise a range of saturated heterocycles are highly desirable. In this thesis, palladium-catalysed directed C(sp3)–H arylation methodology to functionalise unactivated positions of heteroaliphatic rings is explored for the first time. Initially, the synthesis of a range of novel 2,3-difunctionalised pyrrolidines is described. These pyrrolidines are synthesised as single stereoisomers via directed C−H functionalisation at the unactivated 3-position of proline derivatives, representing the first direct functionalisations of unactivated C–H bonds on the pyrrolidine ring. A variety of functionalised and heterocyclic iodoarenes are employed with minimal excess, and the resulting 3-(hetero)arylproline derivatives are transformed in to compounds that comply with desirable criteria for drug discovery. Subsequently, this C–H arylation approach is applied to the synthesis of 3-aryl tetrahydrofuran, tetrahydropyran and piperidine derivatives, where subtle differences in substrate structures were found to alter reactivity significantly. High yields were obtained for each substrate, through the development of a condensed optimisation procedure that employs a limited set of reaction variables designed to cover appropriate reaction space. Reactivity and selectivity is compared across these substrates, and a comparison of the success of different directing groups was undertaken on the THP substrate, which was the only substrate to form trans-configured products as minor components. This condensed optimisation approach was also demonstrated on carbocyclic and acyclic derivatives to demonstrate the flexibility and applicability of this process, enabling direct comparison with literature results. Stereoselective removal of the directing group was also demonstrated on both nitrogen and oxygen heterocycles. Preliminary studies into reaction kinetics and the viability of directing groups at the 3-position of saturated heterocycles are described. The final section provides full experimental details.Open Acces

Synthesis of <i>cis</i>-<i>C</i>-iodo-<i>N</i>-tosyl-aziridines using diiodomethyllithium:Reaction optimization, product scope and stability, and a protocol for selection of stationary phase for chromatography

[Image: see text] The preparation of C-iodo-N-Ts-aziridines with excellent cis-diastereoselectivity has been achieved in high yields by the addition of diiodomethyllithium to N-tosylimines and N-tosylimine–HSO(2)Tol adducts. This addition-cyclization protocol successfully provided a wide range of cis-iodoaziridines, including the first examples of alkyl-substituted iodoaziridines, with the reaction tolerating both aryl imines and alkyl imines. An ortho-chlorophenyl imine afforded a β-amino gem-diiodide under the optimized reaction conditions due to a postulated coordinated intermediate preventing cyclization. An effective protocol to assess the stability of the sensitive iodoaziridine functional group to chromatography was also developed. As a result of the judicious choice of stationary phase, the iodoaziridines could be purified by column chromatography; the use of deactivated basic alumina (activity IV) afforded high yield and purity. Rearrangements of electron-rich aryl-iodoaziridines have been promoted, selectively affording either novel α-iodo-N-Ts-imines or α-iodo-aldehydes in high yield

Regio- and Stereoselective Palladium-Catalyzed C(sp³)–H Arylation of Pyrrolidines and Piperidines with C(3) Directing Groups

The selective synthesis of <i>cis</i>-3,4-disubstituted pyrrolidines and piperidines is achieved by a Pd-catalyzed C–H arylation with excellent regio- and stereoselectivity using an aminoquinoline auxiliary at C(3). The arylation conditions are silver free, use a low catalyst loading, and employ inexpensive K₂CO₃ as a base. Directing group removal is accomplished under new, mild conditions to access amide-, acid-, ester-, and alcohol-containing fragments and building blocks. This C–H arylation protocol enabled a short and stereocontrolled formal synthesis of (−)-paroxetine