Exploration of the P1 residue in 3CL protease inhibitors leading to the discovery of a 2-tetrahydrofuran P1 replacement

The virally encoded 3C-like protease (3CLpro) is a well-validated drug target for the inhibition of coronaviruses including Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Most inhibitors of 3CLpro are peptidomimetic, with a γ-lactam in place of Gln at the P1 position of the pseudopeptide chain. An effort was pursued to identify a viable alternative to the γ-lactam P1 mimetic which would improve physicochemical properties while retaining affinity for the target. Discovery of a 2-tetrahydrofuran as a suitable P1 replacement that is a potent enzymatic inhibitor of 3CLpro in SARS-CoV-2 virus is described herein.

Novel tricyclics (e.g., GSK945237) as potent inhibitors of bacterial type IIA topoisomerases

During the course of our research on the lead optimisation of the NBTI (Novel Bacterial Type II Topoisomerase Inhibitors) class of antibacterials, we discovered a series of tricyclic compounds that showed good Gram-positive and Gram-negative potency. Herein we will discuss the various subunits that were investigated in this series and report advanced studies on compound 1 (GSK945237) which demonstrates good PK and in vivo efficacy properties.

Structural basis of quinolone inhibition of type IIA topoisomerases and target-mediated resistance

Quinolone antibacterials have been used to treat bacterial infections for over 40 years. A crystal structure of moxifloxacin in complex with Acinetobacter baumannii topoisomerase IV now shows the wedge-shaped quinolone stacking between base pairs at the DNA cleavage site and binding conserved residues in the DNA cleavage domain through chelation of a noncatalytic magnesium ion. This provides a molecular basis for the quinolone inhibition mechanism, resistance mutations and invariant quinolone antibacterial structural features.

Design and synthesis of conformationally restricted eight-Membered ring diketones as potential serine protease inhibitors

The design of conformationally restricted eight-membered ring diketones as transition state mimics of the mechanism of action of cyclotheonamides on serine proteases is described. Two target compounds are prepared from mutilin, derived from the natural product pleuromutilin. Compound 3 shows significant inhibition of plasmin and urokinase in enzyme rate assays, but an analogue 4 in which the amide moiety has been omitted does not. An X-ray crystal structure of the diketone 3 confirms the conformational predictions made by molecular modelling.

The carbenoid approach to peptide synthesis

A different approach to the synthesis of dipeptides is described based on the formation of the NHCHR1CONH-CHR2CO bond by carbenoid N-H insertion, rather than the formation of the peptide bond itself. Thus decomposition of triethyl diazophosphonoacetate catalysed by rhodium(II) acetate in the presence of N-protected amino acid amides 8 gives the phosphonates 9. Subsequent Wadsworth-Emmons reaction of 9 with aldehydes in the presence of DBU gives dehydro dipeptides 10. The reaction has been extended to a simple two-step procedure, without the isolation of the intermediate phosphonate, for conversion of a range of amino acid amides 11 into dehydro dipeptides 12 and to an N-methylamide 11 h, and for conversion of a dipeptide to tripeptide (13-->14). Direct conversion, by using methyl diazophenylacetate, of amino acid amides to phenylglycine-containing dipeptides 19 proceeds in good chemical yield, but with poor diastereoselectivity.

RNA as a drug target

Historically, the pharmaceutical industry has focused on proteins, rather than nucleic acids, as drug targets. But recent advances in the fields of RNA synthesis, structure determination and therapeutic target identification make the systematic exploitation of RNA as a drug target a realistic goal.

Chemistry of pseudomonic acid. Part 16. Aryl and heteroaryl ketone derivatives of monic acid

The synthesis, antibacterial activities, murine pharmacokinetic and infection model data for a range of aryl and heteroaryl ketone derivatives of monic acid (2a) are reported. The best results were found for the 3-furyl and 2-methoxy thiazol-5-yl analogues.

Trial into the effects of repeated neck retractions in normal subjects

STUDY DESIGN

This investigation measured the immediate effects of 10, 20, and 30 repeated neck retraction movements on the retraction range of motion and resting neck posture in asymptomatic subjects.

OBJECTIVES

The results provide baseline gross kinematic data concerning the effects of neck retraction movements. Future work involving patients is anticipated and proposed.

SUMMARY OF BACKGROUND INFORMATION

Neck retraction movements are an assessment maneuver and a treatment technique advocated by Robin McKenzie for patients with neck pain. They are a commonly prescribed physical therapy technique used to treat patients with neck pain and dysfunction. No previous studies of this maneuver have been reported.

METHODS

Two groups of 15 subjects, one group 20-29 years old and the other 50-59 years old, participated. Each group performed three sets of 10 repeated movements. The position of the head and neck were recorded by the 3Space Isotrak System using markers placed over the spinous processes of selected vertebrae and the tragus of the ear.

RESULTS

After the repeated movements, no statistically significant difference was found in neck retraction range of motion, but a statistically significant change in the resting neck posture was detected.

CONCLUSIONS

Any changes in neck retraction range of motion observed after the execution of this maneuver in patients with neck pain may be the result of changes in a pathological process. If the postural change were to occur in patients, this treatment maneuver could be beneficial for those attempting to maintain a more retracted neck position for pain relief.

An assessment of relief hospital admissions for elderly patients with dementia

Twenty-five relief admissions for elderly patients with dementia were studied in order to examine the effects of the respite care on the principal carer: 68% of the patients were severely impaired (maximally dependent); 28% markedly impaired (highly dependent). Despite some reservations, carers perceived relief admissions as beneficial to many aspects of their lives and in some cases essential if patients were to remain in the community. It is argued that relief admissions are an essential part of a comprehensive service for patients with dementia in the community.