A General Approach to Optically Pure, α-Methyl Non-Natural Amino Acids: Enabling Unique Peptides as Drug Candidates.

An α-methyl, non-natural amino acid (NNAA) building block equipped with an alkyl halide tail that could be readily transformed into an organozinc was prepared. This single organometallic was cross-coupled to an array of heterocyclic electrophiles using the Pd-PEPPSI-IHeptCl catalyst to produce a wide selection of optically pure α-methyl NNAAs. With these in hand, non-natural peptides are being produced for evaluation in a variety of therapeutic areas in drug discovery.

The History of Flow Chemistry at Eli Lilly and Company.

Flow chemistry was initially used for speed to early phase material delivery in the development laboratories, scaling up chemical transformations that we would not or could not scale up batch for safety reasons. Some early examples included a Newman Kwart Rearrangement, Claisen rearrangement, hydroformylation, and thermal imidazole cyclization. Next, flow chemistry was used to enable safe scale up of hazardous chemistries to manufacturing plants. Examples included high pressure hydrogenation, aerobic oxidation, and Grignard formation reactions. More recently, flow chemistry was used in Small Volume Continuous (SVC) processes, where highly potent oncolytic molecules were produced by fully continuous processes at about 10 kg/day including reaction, extraction, distillation, and crystallization, using disposable equipment contained in fume hoods.

A Continuous Flow Process for LSN647712 via Double Organometallic Additions to Dimethylcarbamyl Chloride.

The ketone intermediate LSN647712 is a key synthetic intermediate for the drug substance lasmiditan manufacturing process. A three-step connected continuous flow process utilizing a Turbo Grignard reagent, N-methylpiperidin-4-ylmagnesium chloride, and lithiated 2,6-dibromopyridine sequentially added to double electrophile (O═C(++) synthon dimethylcarbamyl chloride (DMCC) was developed to deliver the ketone intermediate in a high chemical yield (>85%). This highly productive (>100 g/h lab system) and intensified process (τ ∼ 3 min) yields the product in high purity upon batch reactive crystallization to form a corresponding hydrobromide salt. In addition to the connected plug flow reactor system, the Grignard reagent, N-methylpiperidin-4-ylmagnesium chloride, was also prepared continuously in CSTR as a more soluble LiCl adduct in THF (Turbo Grignard).

Assessing needs for psychiatric treatment in prisoners: 1. Prevalence of disorder.

BACKGROUND: High levels of psychiatric morbidity in prisoners have important implications for services. Assessing Needs for Psychiatric Treatment in Prisoners is an evaluation of representative samples of prisoners in a male and a female prison in London. This paper reports on the prevalence of mental disorders. In a companion paper, we describe how this translates into mental health treatment needs and the extent to which they have been met. METHODS: Prisoners were randomly sampled in a sequential procedure based on the Local Inmate Data System. We interviewed roughly equal numbers from the following groups: male remand; male sentenced prisoners (Pentonville prison); and female remand; female sentenced prisoners (Holloway prison). Structured assessments were made of psychosis, common mental disorders, PTSD, personality disorder and substance abuse. RESULTS: We interviewed 197 male and 171 female prisoners. Psychiatric morbidity in male and female, sentenced and remand prisoners far exceeded in prevalence and severity than in equivalent general population surveys. In particular, 12% met criteria for psychosis; 53.8% for depressive disorders; 26.8% for anxiety disorders; 33.1% were dependent on alcohol and 57.1% on illegal drugs; 34.2% had some form of personality disorder; and 69.1% had two disorders or more. Moreover, in the year before imprisonment, 25.3% had used mental health services. CONCLUSIONS: These rates of mental ill-health and their similarity in remand and sentenced prisoners indicate that diversion of people with mental health problems from the prison arm of the criminal justice system remains inadequate, with serious consequences for well-being and recidivism.

Assessing needs for psychiatric treatment in prisoners: 2. Met and unmet need.

BACKGROUND: In a companion paper, we established high levels of psychiatric morbidity in prisoners (Bebbington et al. Soc Psychiatry Psychiatr Epidemiol, 2016). In the current report, we evaluate how this morbidity translates into specific needs for treatment and the consequent implications for services. Mental health treatment needs and the extent to which they had been met were assessed in a representative sample of prisoners in a male and a female prison in London (Pentonville and Holloway). METHODS: Prisoners were sampled at random in a sequential procedure based on the Local Inmate Data System. We targeted equal numbers of male remand, male sentenced, female remand, and female sentenced prisoners. Following structured assessment of psychosis, common mental disorders, PTSD, personality disorders and disorders of abuse, we used the MRC Needs for Care Assessment (NFCAS) to establish whether potential needs for care in ten areas of mental health functioning were met, unmet, or incapable of being met by services. RESULTS: Data on treatment experience were provided by 360 inmates. Eighty percent of females and 70% of males had at least one need for treatment. Over half (53.7%) of the needs of female prisoners were met, but only one third (36.5%) in males. Needs for medication were unmet in 32% of cases, while those for psychological treatment were unmet in 51%. CONCLUSIONS: Unmet needs for mental health treatment and care were common in the two prisons. This has adverse consequences both for individual prisoners and for the effective functioning of the criminal justice system.

Effects of S-nitrosation and cross-linking of hemoglobin on hypoxic pulmonary vasoconstriction in isolated rat lungs.

Free hemoglobin (Hb) and red blood cells augment hypoxic pulmonary vasoconstriction (HPV) by scavenging nitric oxide (NO). S-nitrosation of Hb (SNO-Hb) may confer vasodilatory properties by allowing release of NO during deoxygenation and/or by interaction with small-molecular weight thiols. Likewise, cross-linking of free Hb may limit its vasoconstrictive effect by preventing abluminal movement of the molecule. We compared the effects of free SNO-Hb and Hb intramolecularly cross-linked at the beta-cysteine 93 residue [Bis(maleidophenyl)-polyethylene glycol2000HbA (Bis-Mal-PEGHb)] to those of free oxyHb on pulmonary artery pressure (PAP), HPV, and exhaled NO (eNO) in isolated, perfused rat lungs. Ventilation of lungs with anoxic gas for 5 minutes reduced perfusate PO2 to 11+/-1.0 Torr. Addition of SNO-Hb or Bis-Mal-PEGHb (100 micromol/L) to buffer perfusate increased normoxic PAP and augmented HPV in similar magnitude as free oxyHb, but had no effect on eNO. Addition of the allosteric modulator inositol hexaphosphate to increase Hb P50 and the thiol glutathione (GSH) to allow removal of NO from Hb via transnitrosation to the perfusate did not reduce augmentation of HPV by SNO-Hb or increase eNO. GSH resulted in an approximately 50% reduction in perfusate [S-nitrosothiol], in association with an increase in perfusate [metHb]. Free SNO-Hb is a net NO scavenger and pulmonary vasoconstrictor in this model, although thiol-mediated release of NO from SNO-Hb does occur. However, release of NO from SNO-Hb was not influenced by deoxygenation-mediated allosteric changes in Hb across a broad range of oxyHb saturation. Cross-linking of Hb does not limit its pulmonary vasoconstrictor effects.

The effect of a bioresorbable matrix barrier in endodontic surgery on the rate of periapical healing: an in vivo study.

The purpose of this prospective clinical study was to assess the rate of healing of periapical bony defects created at the time of endodontic periapical surgery by measuring the densitometric ratio change in periapical osseous tissues, after periapical endodontic surgery was performed, by using or not using Guidor bioresorbable membrane material. Periapical surgeries were performed on 25 patients where nonsurgical root canal therapy had failed and a periapical lesion was present. For inclusion in the study, the osseous defect to be analyzed had to be confined to the apical area, with bone covering the entire root surface coronally, and an intact lingual cortical plate had to be present. A series of radiographs at the 3-, 6-, and 12-month recalls were compared with the radiograph taken immediately after surgery by using digital imaging and a densitometric ratio that gave a numerical estimation of osseous healing. Using repeated-measure ANOVA, it was shown that there was no statistical difference between the rate of healing in those cases where a Guidor resorbable membrane was used and those cases where no membrane was used. The results suggest that placement of a guided tissue membrane over the bony opening created during an endodontic periapical surgical procedure has no beneficial effect on the rate of healing and the added expense to the patient would not be warranted in these cases.

Scope of the asymmetric intramolecular stetter reaction catalyzed by chiral nucleophilic triazolinylidene carbenes.

A highly enantioselective intramolecular Stetter reaction of aromatic and aliphatic aldehydes tethered to different Michael acceptors has been developed. Two triazolium scaffolds have been identified that catalyze the intramolecular Stetter reaction with good reactivity and enantioselectivity. The substrate scope has been examined and found to be broad; both electron-rich and -poor aromatic aldehydes undergo cyclization in high yield and enantioselectivity. The tether can include oxygen, sulfur, nitrogen, and carbon linkers with no detrimental effects. In addition, the incorporation of various tethered Michael acceptors includes amides, esters, thioesters, ketones, aldehydes, and nitriles. The catalyst loading may be reduced to 3 mol % without significantly affecting the reactivity or selectivity of the reaction.

An efficient synthesis of achiral and chiral 1,2,4-triazolium salts: bench stable precursors for N-heterocyclic carbenes.

[reaction: see text] The promising utility of triazolyl N-heterocyclic carbene catalysts in umpolung aldehyde chemistry requires a straightforward reliable synthesis from readily available materials. Herein, we describe the synthesis of a variety of triazolyl N-heterocyclic carbene precursors. The reactions commence from commercially available amino acids and proceed in 44-68% overall yields. The N-heterocyclic salts are air-stable crystalline solids that can be stored with no special precaution and can generate the active catalyst when treated with an appropriate base.

Enantioselective synthesis of quaternary stereocenters via a catalytic asymmetric Stetter reaction.

A new electron-deficient chiral triazolium salt has been shown to catalyze the formation of quaternary stereocenters by an asymmetric intramolecular Stetter reaction. Pentafluorophenyl substitution on an aminoindanol-derived catalyst affords tertiary ether, thioether, and quaternary stereocenters in typically greater than 90% ee and very good chemical yield. Aromatic and aliphatic aldehydes are equally competent substrates for this reaction. The reaction proceeds at room temperature under mild conditions to provide quaternary stereocenters with functional group relationships that are particularly difficult to access by other methods.

A highly enantioselective catalytic intramolecular Stetter reaction.

A family of chiral triazolium salts has been developed for inducing the asymmetric intramolecular Stetter reaction. The use of an aminoindanol-derived catalyst affords optimal results, with the product keto esters formed in 82-97% ee and very good chemical yield. Aromatic and aliphatic aldehydes are equally competent substrates for this reaction. The reaction conditions are reasonably mild and allow the isolation of the newly formed stereocenter without epimerization, although the presumed carbenic intermediates are strong bases.

Inhibition of aquaporin-mediated CO2 diffusion and voltage-gated H+ channels by zinc does not alter rabbit lung CO2 and NO excretion.

Aquaporins (AQs) increase cell membrane CO(2) diffusivity, and it has been proposed that they may serve as transmembrane channels for CO(2) and other small gas molecules. In addition, it has been hypothesized that voltage-gated H(+) channels located on the apical membrane of the alveolar epithelium contribute to CO(2) elimination by the lung. To test whether these membrane proteins contribute to CO(2) elimination in vivo, we measured CO(2) exchange in buffer- and blood-perfused rabbit lungs before and after addition of 0.5 mM ZnCl(2), an inhibitor of both AQ-mediated CO(2) diffusion and voltage-gated H(+) channels. For comparison, red cell and lung carbonic anhydrases (CAs) were inhibited by 0.1 mM methazolamide. ZnCl(2) had no effect on CO(2) exchange when inspired CO(2) was altered between 2% and 5% in 5-min intervals. Pulmonary vascular and airway resistances were not altered by ZnCl(2). In contrast, methazolamide inhibited CO(2) exchange by 30% in buffer-perfused lungs and by 65% in blood-perfused lungs. Exhaled NO concentrations were unaffected by ZnCl(2) or by CA inhibition. Lung capillary gas exchange modelling shows that under normal resting conditions it would be necessary to reduce the alveolar-capillary membrane CO(2) diffusion capacity by >90% to lower CO(2) elimination by 10%. Therefore we conclude that red cell and lung AQs and voltage-gated H(+) channels in the alveolar epithelium contribute minimally to normal physiological CO(2) elimination.

Contributions of nitric oxide synthase isozymes to exhaled nitric oxide and hypoxic pulmonary vasoconstriction in rabbit lungs.

We investigated the source(s) for exhaled nitric oxide (NO) in isolated, perfused rabbits lungs by using isozyme-specific nitric oxide synthase (NOS) inhibitors and antibodies. Each inhibitor was studied under normoxia and hypoxia. Only nitro-L-arginine methyl ester (L-NAME, a nonselective NOS inhibitor) reduced exhaled NO and increased hypoxic pulmonary vasoconstriction (HPV), in contrast to 1400W, an inhibitor of inducible NOS (iNOS), and 7-nitroindazole, an inhibitor of neuronal NOS (nNOS). Acetylcholine-mediated stimulation of vascular endothelial NOS (eNOS) increased exhaled NO and could only be inhibited by L-NAME. Selective inhibition of airway and alveolar epithelial NO production by nebulized L-NAME decreased exhaled NO and increased hypoxic pulmonary artery pressure. Immunohistochemistry demonstrated extensive staining for eNOS in the epithelia, vasculature, and lymphatic tissue. There was no staining for iNOS but moderate staining for nNOS in the ciliated cells of the epithelia, lymphoid tissue, and cartilage cells. Our findings show virtually all exhaled NO in the rabbit lung is produced by eNOS, which is present throughout the airways, alveoli, and vessels. Both vascular and epithelial-derived NO modulate HPV.