Thermal and photochemical annulation of vinyl azides to 2-aminoimidazoles.

2-Aminoimidazoles represent useful synthons for incorporation into medicinal compounds. They provide hydrogen bonding loci, water solubilizing properties and convenient handles for further synthetic elaboration. The rapid and facile generation of diverse 2-aminoimidazoles via tandem addition cyclization reaction of vinyl azides and cyanamide has been investigated. These reactions proceeded through either thermal or photochemical activation of vinyl azides and demonstrated wide substrate scope. In the photochemical reaction, blue light (456 nm) alone triggered photolysis of the azide without the addition of a photocatalyst. Possible reaction mechanisms in the context of substrate reactivity are discussed.

Conversion of a Benzofuran Ester to an Amide through an Enamine Lactone Pathway: Synthesis of HCV Polymerase Inhibitor GSK852A.

HCV NS5B polymerase inhibitor GSK852A (1) was synthesized in only five steps from ethyl 4-fluorobenzoylacetate (3) in 46% overall yield. Key to the efficient route was the synthesis of the highly functionalized benzofuran core 15 from the ß-keto ester in one pot and the efficient conversion of ester 6 to amide 19 via enamine lactone 22. Serendipitous events led to identification of the isolable enamine lactone intermediate 22. Single crystal X-ray diffraction and NMR studies supported the intramolecular hydrogen bond shown in enamine lactone 22. The hydrogen bond was considered an enabler in the proposed pathway from ester 6 to enamine lactone 22 and its rearrangement to amide 19. GSK852A (1) was obtained after reductive amination and mesylation with conditions amenable to the presence of the boronic acid moiety which was considered important for the desirable pharmacokinetics of 1. The overall yield of 46% in five steps was a significant improvement to the previous synthesis from the same ß-keto ester in 5% yield over 13 steps.

Lead identification and structure-activity relationships of heteroarylpyrazole arylsulfonamides as allosteric CC-chemokine receptor 4 (CCR4) antagonists.

A knowledge-based library of aryl 2,3-dichlorophenylsulfonamides was synthesised and screened as human CCR4 antagonists, in order to identify a suitable hit for the start of a lead-optimisation programme. X-ray diffraction studies were used to identify the pyrazole ring as a moiety that could bring about intramolecular hydrogen bonding with the sulfonamide NH and provide a clip or orthogonal conformation that was believed to be the preferred active conformation. Replacement of the core phenyl ring with a pyridine, and replacement of the 2,3-dichlorobenzenesulfonamide with 5-chlorothiophenesulfonamide provided compound 33 which has excellent physicochemical properties and represents a good starting point for a lead optimisation programme. Electronic structure calculations indicated that the preference for the clip or orthogonal conformation found in the small molecule crystal structures of 7 and 14 was in agreement with the order of potency in the biological assay.

From formulation to structure: 3D electron diffraction for the structure solution of a new indomethacin polymorph from an amorphous solid dispersion.

3D electron diffraction (3DED) is increasingly employed to determine molecular and crystal structures from micro-crystals. Indomethacin is a well known, marketed, small-molecule non-steroidal anti-inflammatory drug with eight known polymorphic forms, of which four structures have been elucidated to date. Using 3DED, we determined the structure of a new ninth polymorph, σ, found within an amorphous solid dispersion, a product formulation sometimes used for active pharmaceutical ingredients with poor aqueous solubility. Subsequently, we found that σ indomethacin can be produced from direct solvent evaporation using dichloromethane. These results demonstrate the relevance of 3DED within drug development to directly probe product formulations.

Mortality in Barrett's esophagus: three decades of experience at a single center.

BACKGROUND AND STUDY AIMS: There is a view that the majority of deaths in patients with Barrett's esophagus are from causes other than esophageal adenocarcinoma (EAC). The aim of this analysis was to establish the pattern of mortality for a number of causes in patients with Barrett's esophagus. PATIENTS AND METHODS: This was a single-center prospective cohort study of patients from Rotherham District General Hospital, which is a secondary referral center. The cohort consisted of 1239 patients who were diagnosed with Barrett's esophagus between April 1978 and March 2009.  Follow-up for mortality was undertaken by "flagging" the patients with the NHS Information Center. Causes of death were compared with UK Office of National Statistics age- and sex-specific mortality data for 1999, the median year of diagnosis. Analysis was by a "person - years at risk" calculation from date of diagnosis. RESULTS: The ratio of observed deaths from EAC compared with those expected in this cohort was 25.02 - a very large excess. There was no difference in mortality from colorectal cancer or circulatory disease and there were fewer deaths from cancers other than esophageal adenocarcinoma and colon cancer compared with national statistics. There was a small statistically significant difference in mortality from all causes but this disappeared completely when deaths from esophageal adenocarcinoma were excluded. CONCLUSIONS: Overall, mortality in Barrett's esophagus is increased significantly but only as a result of the large excess of deaths from EAC. This strengthens the case for endoscopic surveillance if successful interventions can be undertaken in patients with Barrett's esophagus to prevent development of esophageal adenocarcinoma.

Studying the origin of the antiferromagnetic to spin-canting transition in the beta-p-NCC6F4CNSSN* molecular magnet.

The crystal structure of the spin-canted antiferromagnet beta-p-NCC(6)F(4)CNSSN* at 12 K (reported in this work) was found to adopt the same orthorhombic space group as that previously determined at 160 K. The change in the magnetic properties of these two crystal structures has been rigorously studied by applying a first-principles bottom-up procedure above and below the magnetic transition temperature (36 K). Calculations of the magnetic exchange pathways on the 160 K structure reveal only one significant exchange coupling (J(d1)=-33.8 cm(-1)), which generates a three-dimensional diamond-like magnetic topology within the crystal. The computed magnetic susceptibility, chi(T), which was determined by using this magnetic topology, quantitatively reproduces the experimental features observed above 36 K. Owing to the anisotropic contraction of the crystal lattice, both the geometry of the intermolecular contacts at 12 K and the microscopic J(AB) radical-radical magnetic interactions change: the J(d1) radical-radical interaction becomes even more antiferromagnetic (-43.2 cm(-1)) and two additional ferromagnetic interactions appear (+7.6 and +7.3 cm(-1)). Consequently, the magnetic topologies of the 12 and 160 K structures differ: the 12 K magnetic topology exhibits two ferromagnetic sublattices that are antiferromagnetically coupled. The chi(T) curve, computed below 36 K at the limit of zero magnetic field by using the 12 K magnetic topology, reproduces the shape of the residual magnetic susceptibility (having subtracted the contribution to the magnetization arising from spin canting). The evolution of these two ferromagnetic J(AB) contributions explains the change in the slope of the residual magnetic susceptibility in the low-temperature region.

Automated Measurements of Key Morphological Features of Human Embryos for IVF.

A major challenge in clinical In-Vitro Fertilization (IVF) is selecting the highest quality embryo to transfer to the patient in the hopes of achieving a pregnancy. Time-lapse microscopy provides clinicians with a wealth of information for selecting embryos. However, the resulting movies of embryos are currently analyzed manually, which is time consuming and subjective. Here, we automate feature extraction of time-lapse microscopy of human embryos with a machine-learning pipeline of five convolutional neural networks (CNNs). Our pipeline consists of (1) semantic segmentation of the regions of the embryo, (2) regression predictions of fragment severity, (3) classification of the developmental stage, and object instance segmentation of (4) cells and (5) pronuclei. Our approach greatly speeds up the measurement of quantitative, biologically relevant features that may aid in embryo selection.

The Optimization of a Novel, Weak Bromo and Extra Terminal Domain (BET) Bromodomain Fragment Ligand to a Potent and Selective Second Bromodomain (BD2) Inhibitor.

The profound efficacy, yet associated toxicity of pan-BET inhibitors is well documented. The possibility of an ameliorated safety profile driven by significantly selective (>100-fold) inhibition of a subset of the eight bromodomains is enticing, but challenging given the close homology. Herein, we describe the X-ray crystal structure-directed optimization of a novel weak fragment ligand with a pan-second bromodomain (BD2) bias, to potent and highly BD2 selective inhibitors. A template hopping approach, enabled by our parallel research into an orthogonal template (15, GSK046), was the basis for the high selectivity observed. This culminated in two tool molecules, 20 (GSK620) and 56 (GSK549), which showed an anti-inflammatory phenotype in human whole blood, confirming their cellular target engagement. Excellent broad selectivity, developability, and in vivo oral pharmacokinetics characterize these tools, which we hope will be of broad utility to the field of epigenetics research.

An investigation into the electrophilic cyclisation of N-acyl-pyrrolidinium ions: a facile synthesis of pyrrolo-tetrahydroisoquinolones and pyrrolo-benzazepinones.

The triflic acid-mediated cyclisation of N-arylmethyl- and N-arylethyl-acylpyrrolidinium ions gave moderate to good yields of pyrrolo-tetrahydroisoquinolones and pyrrolo-benzazepinones respectively. Electron-donating R substituents enhanced the rate of reaction and gave higher yields than electron-withdrawing substituents. Substituents on the methyl or ethyl chain in general enhanced the reaction, unless sterically encumbered. The equivalent acylpiperidinium ions cyclised much slower and in lower yield.

Discovery of an Orally Bioavailable Pan αv Integrin Inhibitor for Idiopathic Pulmonary Fibrosis.

The heterodimeric transmembrane αv integrin receptors have recently emerged as potential targets for the treatment of idiopathic pulmonary fibrosis. Herein, we describe how subtle modifications of the central aromatic ring of a series of phenylbutyrate-based antagonists of the vitronectin receptors αvß3 and αvß5 significantly change the biological activities against αvß6 and αvß8. This resulted in the discovery of a pan αv antagonist (compound 39, 4-40 nM for the integrin receptors named above) possessing excellent oral pharmacokinetic properties in rats (with a clearance of 7.6 mL/(min kg) and a bioavailability of 97%).

Identification of GSK3186899/DDD853651 as a Preclinical Development Candidate for the Treatment of Visceral Leishmaniasis.

The leishmaniases are diseases that affect millions of people across the world, in particular visceral leishmaniasis (VL) which is fatal unless treated. Current standard of care for VL suffers from multiple issues and there is a limited pipeline of new candidate drugs. As such, there is a clear unmet medical need to identify new treatments. This paper describes the optimization of a phenotypic hit against Leishmania donovani, the major causative organism of VL. The key challenges were to balance solubility and metabolic stability while maintaining potency. Herein, strategies to address these shortcomings and enhance efficacy are discussed, culminating in the discovery of preclinical development candidate GSK3186899/DDD853651 (1) for VL.

Discovery of Novel 1-Cyclopentenyl-3-phenylureas as Selective, Brain Penetrant, and Orally Bioavailable CXCR2 Antagonists.

CXCR2 has emerged as a therapeutic target for not only peripheral inflammatory diseases but also neurological abnormalities in the central nervous system (CNS). Herein, we describe the discovery of a novel 1-cyclopentenyl-3-phenylurea series as potent and CNS penetrant CXCR2 antagonists. Extensive SAR studies, wherein molecules' property forecast index (PFI) was carefully optimized for overall balanced developability profiles, led to the discovery of the advanced lead compound 68 with a desirable PFI. Compound 68 demonstrated good in vitro pharmacology with excellent selectivity over CXCR1 and other chemokine receptors. Rat and dog pharmacokinetics (PK) revealed good oral bioavailability, high oral exposure, and desirable elimination half-life of the compound in both species. In addition, the compound demonstrated dose-dependent efficacy in the in vivo pharmacology neutrophil infiltration "air pouch" model in rodents after oral administration. Further, compound 68 is a CNS penetrant molecule with high unbound fraction in brain tissue.

Reflux rising! An essay on witnessing a disease in evolution.

BACKGROUND AND AIM: The prevalence of gastro-oesophageal reflux disease is thought to be rising but supporting evidence is sparse. We assessed trends from data prospectively collected over 25 years at our centre which serves Rotherham's 250000 population. PATIENTS AND METHODS: Detailed computerised records have been kept of all patients investigated for upper gastrointestinal symptoms. DEFINITION: Erosive oesophagitis=endoscopy-verified erosive changes. Non-erosive reflux=heartburn+/-regurgitation but normal endoscopy. Gastro-oesophageal reflux disease=erosive oesophagitis+non-erosive reflux, i.e. total. RESULTS: The data, presented in 5-year time periods spanning 1977-2001, showed four major changing trends. (1) The numbers with newly diagnosed gastro-oesophageal reflux disease rose markedly, affecting both erosive oesophagitis and non-erosive reflux. Gastro-oesophageal reflux disease: n=714; 1587; 2381; 3812; 3880. (2) The proportion of women affected rose from 0.36 to 0.82. (3) Gastro-oesophageal reflux disease patients were older than the general population; the mean age at presentation rose from 48.0 to 53.5 years. (4) Presentation with haemorrhage (percentage of erosive oesophagitis) rose from 5.2% to 10.9% but, as with stricture (around 4%), remained uncommon. Throughout, few (4.4%) changed from non-erosive reflux to erosive oesophagitis. CONCLUSION: The marked increase in gastro-oesophageal reflux disease cannot be accounted for by greater awareness alone for the demographic profile has changed, or by misclassification as erosive oesophagitis was diagnosed on endoscopic appearances. The dramatic five-fold increase in gastro-oesophageal reflux disease is a new phenomenon, perhaps an example of a disease in evolution.

Day case laparoscopic herniorraphy. A NICE procedure with a long learning curve.

BACKGROUND: The aim of this study was to evaluate day case laparoscopic herniorraphy (LH) and to ascertain the impact of trainee surgeons on its performance. METHODS: We performed a prospective study of ambulatory laparoscopic transabdominal preperitoneal herniorraphies performed in a dedicated day surgical unit between March 1996 and October 2003. RESULTS: A total of 840 herniorraphies were performed in 706 consecutive patients. Surgery was performed by 15 higher surgical trainees and three consultant surgeons. The mean operating times for trainees were longer for unilateral (48.4 +/- 0.98 vs 41.4 +/- 0.87 min, p < 0.05) and bilateral (69.0 +/- 3.24 vs 53.0 +/- 1.68 min, p < 0.05) repairs than for consultants. Subgroup analysis demonstrated that after an experience of 40 procedures, trainee times approached those of the consultants (41.39 +/- 1.17 vs 41.4 +/- 0.87 min, p= 0.31). LH repair was well tolerated and associated with minimal postoperative pain and nausea. Mean pain scores postoperatively and at 24 h were 2.69 +/- 0.11 and 2.07 +/- 0.09, respectively. Mean nausea scores postoperatively and at 24 h were 0.34 +/- 0.06 and 0.22 +/- 0.06, respectively. Ninety-three percent of patients (n = 657) were discharged within 8 h. There were two conversions to an open procedure (0.1%) and two significant complications (0.1%). Ninety-five percent of patients who responded to our questionnaire (n = 398/419) were satisfied with surgery and would undergo day case laparoscopic herniorraphy again. CONCLUSIONS: Laparoscopic herniorraphy is a safe technique suitable for day case surgery. Operator experience dictates duration of surgery. Trainees' operating times approach those of consultants after 40 procedures. Prolonged operating times and increased cost are not justifiable reasons for not recommending LH.

Laparoscopic fundoplication: a 10-year learning curve.

BACKGROUND: Laparoscopic Nissen fundoplication (LNF) has become the most common surgical treatment for gastroesophageal reflux disease (GERD). Controversies still exist regarding the operative technique and the durability of the procedure. METHODS: A retrospective study of 808 patients undergoing 838 LNF for GERD at a tertiary referral center was undertaken. Demographic, perioperative, and follow-up data had been entered onto the unit database. RESULTS: During a median follow-up period of 60 months (range, 2-120 months), heartburn decreased to 3% of the patients (19/645) and regurgitation to 2% (11/582) (p < 0.01). Respiratory symptoms improved in 69 (85%) of 81 patients (p < 0.01). The incidence of postoperative dysphagia was unaffected by the use of an intraesophageal bougie (odds ratio [OR], 1.16; 95% confidence interval [CI], 0.82-1.64; p = 0.41) or division of the short gastric vessels (OR, 0.84; 95% CI, 0.42-1.07; p = 0.72). In the immediate postoperative period, the incidence of abdominal symptoms increased by 10% (p < 0.01) and dysphagia by 16% (p < 0.01). After 10 postoperative years, only 3% (30/484) were found to have abdominal symptoms, whereas the incidence of dysphagia declined to zero. CONCLUSION: The findings show that LNF is a safe and effective procedure with long-term durability. Abdominal symptoms and dysphagia are the principal postoperative complaints, which improve with time. Personal preference should dictate the use of a bougie, division of the short gastric vessels, or both.

A prospective study of ambulatory laparoscopic cholecystectomy: training economic, and patient benefits.

BACKGROUND: Even though ambulatory laparoscopic cholecystectomy (ALC) is safe and cost effective, this approach has yet to gain acceptance in the United Kingdom. We report our 5-year experience of ALC with emphasis on its appropriateness for higher surgical training. METHODS: Between July 1997 and July 2002, patients with symptomatic cholelithiasis who met with appropriate criteria underwent ALC. Surgery was performed either by a consultant surgeon or a higher surgical trainee (HST) under direct supervision in our dedicated day surgery unit. Data were recorded prospectively and patients were interviewed postoperatively by an independent researcher. RESULTS: There were 269 patients (231 female and 38 male) with a median age of 46 years (range 17-76). Conversion to open cholecystectomy was necessary in three cases (1%). Of the patients, 79% (213) were discharged within 8 hours of surgery; 95% (256) were discharged on the same day. Thirteen patients (5%) required overnight admission as inpatients. An HST performed 166 (62%) of the procedures. There was a statistically significant difference in operating time between consultants (41 min) and trainees (47 min, P = 0.001) but no significant difference in clinical outcome or patient satisfaction. The mean procedural cost to the hospital was 768 pound sterling for ALC compared with 1430 pound sterling for an inpatient operation. Of patients, 87% expressed satisfaction with the day case operation. CONCLUSION: Our results for ALC compare favorably with published series. In addition, we have demonstrated that the operation can be performed safely by HST under direct supervision without compromising operating lists or safety.

Quantitative study of synaptophysin immunoreactivity of cerebral cortex and spinal cord in motor neuron disease.

Synaptophysin immunoreactivity can be quantified by image analysis to evaluate loss of presynaptic terminals in human neurodegenerative diseases. The extent and regional distribution of such loss is reported in motor neuron disease (MND). Autopsy samples of spinal cord and cerebral cortex were examined from 28 cases of MND and 28 age and sex matched controls. The MND group included individuals with amyotrophic lateral sclerosis (17[ALS]), and progressive muscular atrophy (11[PMA]). In the spinal cord, there was significant reduction of presynaptic terminals in the lateral ventral horn (15%) in both the ALS (p < 0.01) and PMA (p < 0.05) groups. Perisomatic synaptophysin profiles on lower motor neurons are preserved late in the disease and are not related to corticospinal innervation. Less marked presynaptic loss was demonstrable more widely in the medial ventral, intermediate and dorsal spinal grey matter (10%) in both ALS (p = 0.03) and PMA (p = 0.05). In the cerebral cortex no synaptic loss was demonstrated in motor or anterior cingulate regions in any of the MND cases. Spinal degeneration in MND is associated with loss of presynaptic terminals in all grey matter regions. It is most marked in the limb motor neuron area and is independent of corticospinal tract degeneration. The cerebral pathology of ALS is not associated with significant loss of presynaptic terminals in the cortical areas studied.

The management of refractory gastric ulcer using H2-receptor antagonists.

BACKGROUND: There is little information on the natural history of refractory gastric ulcer, defined as non-healing on cimetidine > or = 1 g daily given for at least 3 months. SETTING: A district general hospital serving an industrial population. METHODS: Patients with refractory gastric ulcer had their treatment extended and/or the dose increased, and upon healing the majority were put on maintenance treatment with cimetidine 400 mg nightly or 1 g daily and their progress was followed. RESULTS: Of 536 patients with gastric ulcer, 74 (14%) were refractory. Fifty of the 74 (68%) refractory gastric ulcer patients were refractory on their very first course of cimetidine. They had no distinguishing demographic features. Healing occurred in 62 patients (84%) after a mean treatment period of 11.1 months; 28 patients required cimetidine > or = 2 g daily. Eleven of 23 (48%) patients relapsed on maintenance with cimetidine 400 mg compared with seven of 24 (29%) on 1 g daily. A total of 22 out of 62 (35%) relapsed; nine had a second refractory recurrence but none thereafter. Eleven patients were operated upon, seven for failed medical treatment. Only two patients eventually proved to have malignant disease. CONCLUSIONS: Refractory gastric ulcer is uncommon, transient and rarely malignant. Most patients can be satisfactorily managed medically.

Comparison of 40 mg famotidine nightly and 150 mg ranitidine b.d.: ulcer healing and symptom relief in benign gastric ulcer.

Two hundred and eight patients with benign gastric ulcers seen on endoscopy were recruited by 13 hospitals in the United Kingdom and Ireland into this double-blind study. Patients were assigned by pre-randomized schedule to 8 weeks of treatment with either 40 mg famotidine at night or 150 mg ranitidine b.d. Repeat endoscopy confirmed complete ulcer healing in 62 of 77 evaluable patients in the famotidine group (81%) and 58 of 71 in the ranitidine group (82%). The treatments were equally effective in promptly relieving day and night pain. Adverse events were uncommon; dizziness and headaches were the most frequently reported in both groups. In conclusion, night-time famotidine is as effective as twice daily ranitidine in healing benign gastric ulcers and provides similarly rapid symptomatic relief.