Disparities in Genetic Testing for Neurologic Disorders.

BACKGROUND AND OBJECTIVES: Genetic testing is now the standard of care for many neurologic conditions. Health care disparities are unfortunately widespread in the US health care system, but disparities in the utilization of genetic testing for neurologic conditions have not been studied. We tested the hypothesis that access to and results of genetic testing vary according to race, ethnicity, sex, socioeconomic status, and insurance status for adults with neurologic conditions. METHODS: We analyzed retrospective data from patients who underwent genetic evaluation and testing through our institution's neurogenetics program. We tested for differences between demographic groups in 3 steps of a genetic evaluation pathway: (1) attending a neurogenetic evaluation, (2) completing genetic testing, and (3) receiving a diagnostic result. We compared patients on this genetic evaluation pathway with the population of all neurology outpatients at our institution, using univariate and multivariable logistic regression analyses. RESULTS: Between 2015 and 2022, a total of 128,440 patients were seen in our outpatient neurology clinics and 2,540 patients underwent genetic evaluation. Black patients were less than half as likely as White patients to be evaluated (odds ratio [OR] 0.49, p < 0.001), and this disparity was similar after controlling for other demographic factors in multivariable analysis. Patients from the least wealthy quartile of zip codes were also less likely to be evaluated (OR 0.67, p < 0.001). Among patients who underwent evaluation, there were no disparities in the likelihood of completing genetic testing, nor in the likelihood of a diagnostic result after adjusting for age. Analyses restricted to specific indications for genetic testing supported these findings. DISCUSSION: We observed unequal utilization of our clinical neurogenetics program for patients from marginalized and minoritized demographic groups, especially Black patients. Among patients who do undergo evaluation, all groups benefit similarly from genetic testing when it is indicated. Understanding and removing barriers to accessing genetic testing will be essential to health care equity and optimal care for all patients with neurologic disorders.

Genetic testing in adults with neurologic disorders: indications, approach, and clinical impacts.

The role of genetic testing in neurologic clinical practice has increased dramatically in recent years, driven by research on genetic causes of neurologic disease and increased availability of genetic sequencing technology. Genetic testing is now indicated for adults with a wide range of common neurologic conditions. The potential clinical impacts of a genetic diagnosis are also rapidly expanding, with a growing list of gene-specific treatments and clinical trials, in addition to important implications for prognosis, surveillance, family planning, and diagnostic closure. The goals of this review are to provide practical guidance for clinicians about the role of genetics in their practice and to provide the neuroscience research community with a broad survey of current progress in this field. We aim to answer three questions for the neurologist in practice: Which of my patients need genetic testing? What testing should I order? And how will genetic testing help my patient? We focus on common neurologic disorders and presentations to the neurology clinic. For each condition, we review the most current guidelines and evidence regarding indications for genetic testing, expected diagnostic yield, and recommended testing approach. We also focus on clinical impacts of genetic diagnoses, highlighting a number of gene-specific therapies recently approved for clinical use, and a rapidly expanding landscape of gene-specific clinical trials, many using novel nucleotide-based therapeutic modalities like antisense oligonucleotides and gene transfer. We anticipate that more widespread use of genetic testing will help advance therapeutic development and improve the care, and outcomes, of patients with neurologic conditions.

Preimplantation Genetic Testing for Adult-Onset Neurodegenerative Disease: Considerations for Access, Utilization, and Counseling.

Preimplantation genetic testing for monogenic conditions (PGT-M), formerly called preimplantation genetic diagnosis, is a specialized assisted reproduction technique that aims to reduce the risk of a pregnancy inheriting a monogenic condition. Despite calls to increase awareness and prepare neurologists for discussing PGT-M with patients and their families, no guidelines currently exist. When introducing PGT-M to those who may be interested in using it, there are major factors for discussion, including (1) genetic considerations (e.g., requirement for a confirmed genetic diagnosis; timing of genetic test results); (2) practical considerations (e.g., access to PGT-M and genetic services); (3) technical considerations (e.g., factors that can affect the success rate of PGT-M); and (4) psychosocial and ethical considerations (e.g., predictive testing for asymptomatic family members; family dynamics and values). Here, our team of neurologists and specialized genetic counselors discusses the current state of genetic characterization in adult-onset neurodegenerative conditions and highlights the major factors that should be considered when discussing PGT-M with families.

Poly(2-methoxyethyl acrylate) (PMEA) improves the thromboresistance of FRED flow diverters: a thrombogenic evaluation of flow diverters with human blood under flow conditions.

BACKGROUND: Surface modification of flow-diverting stents has been explored to reduce thrombus-related complications that may arise under clinical use. This study investigated the thromboresistant properties of the flow redirection endoluminal device (FRED) X, a flow diverter treated with a copolymer of poly(2-methoxyethyl acrylate) (PMEA; X Technology). METHODS: The performance of FRED, FRED X, and Pipeline Flex with Shield Technology (sPED) was evaluated in an in vitro blood loop model. Blood activation level was assessed by the concentration of thrombin-antithrombin complex (TAT), ß-thromboglobulin (ß-TG), and platelet count, and qualitatively by scanning electron microscopy (SEM). Cellular adhesion characteristics were measured using human aortic endothelial cells that were seeded on flat sheets mimicking the surface of FRED, FRED X, and sPED, and evaluated with fluorescence microscopy. Statistical comparisons were conducted using one-way analysis of variance (ANOVA) with Tukey post hoc tests. RESULTS: FRED X, sPED, and control blood loops showed significantly reduced blood activation levels (TAT and ß-TG) compared with FRED (p<0.01). Consequently, FRED showed a significant decrease in platelet count compared with FRED X, sPED, and control loops (p<0.01). SEM imaging showed the lowest accumulation of blood cell-like deposits on FRED X compared with sPED and FRED, while FRED had the highest accumulation. Endothelial cells adhered and were widely spread on X Technology-treated sheets, while minimal cell adhesion was observed on phosphorylcholine-treated sheets. CONCLUSION: The X Technology surface modification of FRED X demonstrated superior thromboresistant properties over untreated FRED while maintaining comparable cellular adhesion. Taken together, these properties may help mitigate material-related thromboembolic complications.

Assessing barriers to the career ladder and professional development for ethnic minority genetic counselors in the United States.

Ethnic diversity is not reflected within healthcare professions, including genetic counseling, where lack of growth and membership among minority colleagues extends to upper-level and executive roles. While diversity and inclusion-based topics have been emphasized, studies on potential barriers to career advancement in the field of genetic counseling have not received the same attention. Our study examined the current state of mentorship and sponsorship programs, the presence of diversity and inclusion initiatives, and opportunities for career advancement through the lens of a minority genetic counselor. Practicing genetic counselors in the United States identifying as part of any racial group, other than non-Hispanic White alone, were recruited through the Minority Genetics Professionals Network for survey participation. A 31-item survey was fully completed by 19 practicing genetic counselors from a variety of ethnic backgrounds. Data were analyzed using descriptive statistics and thematic analysis, allowing for individual stories and accounts to be amplified. Results showed 16 of 19 participants had never been promoted in their current employment setting. Additionally, 7 out of 19 respondents disagreed or strongly disagreed that their company had a commitment to an ethnically diverse workforce within upper-level positions. Prominent themes identified from open-ended responses included lack of social connection with supervisors and the cross-race effect, a term referencing a tendency for individuals to better recognize members of their own race or ethnicity than others. Additional themes revealed feelings of isolation, need for support from White colleagues, as well as desired emphasis on sponsorship tailored toward professional growth. These findings demonstrate a need for proactive involvement in reaching ethnic and racial minority genetic counselors through companywide policy efforts, support and advocacy from White colleagues, and modification of cultural perception frameworks. Further focus and emphasis on these distinct but critical topics may be important in promoting increased diversity in upper-level positions in the field of genetic counseling.

Transitioning to telegenetics in the COVID-19 era: Patient satisfaction with remote genetic counseling in adult neurology.

The COVID-19 pandemic rapidly changed genetic counseling services across the United States. At the University of Pennsylvania (UPenn), a large academic hospital in an urban setting, nearly all genetic counseling (GC) visits for adult-onset disorders within the Department of Neurology were conducted via secure videoconferencing (telegenetics) or telephone between March and December 2020. Although telemedicine services have been steadily emerging, many clinical programs, including the neurogenetics program at UPenn, had not built infrastructure or widely utilized these services prior to the pandemic. Thus, little is known about patient attitudes toward receiving clinical GC services remotely. From May 18 to October 18, 2020, all individuals seen remotely for GC in adult neurology via telephone or telegenetics were surveyed about their satisfaction with telehealth GC (N = 142), with a response rate of 42% (N = 60/142). Telephone and telegenetics services were referred to as 'telehealth' in the surveys to capture patient perspectives on all remote GC services, though the majority (N = 49/60) of these visits were completed via telegenetics. Surveys included the modified telehealth usability questionnaire (MTUQ), genetic counseling satisfaction scale (GCSS), and novel questions about future telehealth use. Preliminary results suggest that patients were satisfied with receiving remote GC services in adult neurology, with most participants strongly agreeing to all items about satisfaction with telehealth. Just 2% of participants preferred only in-person visits in the future, but every participant was willing to consider using telehealth for future visits if their genetic counselor felt it was appropriate. Most participants preferred a hybrid model (73%), and some (25%) preferred only telehealth for future visits. Additionally, we found no differences in satisfaction with remote services based on visit type (initial vs. results disclosure) nor age. We conclude that remote GC is an acceptable method for the provision of services in adult neurology that is well-received by patients.

Cation-Independent Mannose 6-Phosphate Receptor Deficiency Enhances ß-Cell Susceptibility to Palmitate.

Palmitate attenuates insulin secretion and reduces the viability of insulin-producing cells. Previous studies identified the aberrant palmitoylation or mispalmitoylation of proteins as one mechanism by which palmitate causes ß-cell damage. In this report, we identify a role for lysosomal protein degradation as a mechanism by which ß cells defend themselves against excess palmitate. The cation-independent mannose 6-phosphate receptor (CI-MPR) is responsible for the trafficking of mannose 6-phosphate-tagged proteins to lysosomes via Golgi sorting and from extracellular locations through endocytosis. RINm5F cells, which are highly sensitive to palmitate, lack CI-MPR. The reconstitution of CI-MPR expression attenuates the induction of endoplasmic reticulum (ER) stress and the toxic effects of palmitate on RINm5F cell viability. INS832/13 cells express CI-MPR and are resistant to the palmitate-mediated loss of cell viability. The reduction of CI-MPR expression increases the sensitivity of INS832/13 cells to the toxic effects of palmitate treatment. The inhibition of lysosomal acid hydrolase activity by weak base treatment of islets under glucolipotoxic conditions causes islet degeneration that is prevented by the inhibition of protein palmitoylation. These findings indicate that defects in lysosomal function lead to the enhanced sensitivity of insulin-producing cells to palmitate and support a role for normal lysosomal function in the protection of ß cells from excess palmitate.

Poly(dimethyltin glutarate) as a prospective material for high dielectric applications.

Poly(dimethyltin glutarate) is presented as the first organometallic polymer, a high dielectric constant, and low dielectric loss material. Theoretical results correspond well in terms of the dielectric constant. More importantly, the dielectric constant can be tuned depending on the solvent a film of the polymer is cast from. The breakdown strength is increased through blending with a second organometallic polymer.

Effect of incorporating aromatic and chiral groups on the dielectric properties of poly(dimethyltin esters).

High-dielectric constant materials are critical for numerous applications such as photovoltaics, photonics, transistors, and capacitors. There are numerous polymers used as dielectric layers in these applications but can suffer from having a low dielectric constant, small band gap, or ferroelectricity. Here, the structure-property relationship of various poly(dimethyltin esters) is described that look to enhance the dipolar and atomic polarization component of the dielectric constant. These polymers are also modeled using first principles calculations based on density functional theory (DFT) to predict such values as the total, electronic, and ionic dielectric constant as well as structure. A strong correlation is achieved between the theoretical and experimental values with the polymers exhibiting dielectric constants >4.5 with dissipation on the order of 10(-3) -10(-2) .

Rationally designed polyimides for high-energy density capacitor applications.

Development of new dielectric materials is of great importance for a wide range of applications for modern electronics and electrical power systems. The state-of-the-art polymer dielectric is a biaxially oriented polypropylene (BOPP) film having a maximal energy density of 5 J/cm(3) and a high breakdown field of 700 MV/m, but with a limited dielectric constant (∼2.2) and a reduced breakdown strength above 85 °C. Great effort has been put into exploring other materials to fulfill the demand of continuous miniaturization and improved functionality. In this work, a series of polyimides were investigated as potential polymer materials for this application. Polyimide with high dielectric constants of up to 7.8 that exhibits low dissipation factors (<1%) and high energy density around 15 J/cm(3), which is 3 times that of BOPP, was prepared. Our syntheses were guided by high-throughput density functional theory calculations for rational design in terms of a high dielectric constant and band gap. Correlations of experimental and theoretical results through judicious variations of polyimide structures allowed for a clear demonstration of the relationship between chemical functionalities and dielectric properties.

Immunoproteasome Activation During Early Antiviral Response in Mouse Pancreatic ß-cells: New Insights into Auto-antigen Generation in Type I Diabetes?

Type 1 diabetes results from autoimmune destruction of the insulin producing pancreatic ß-cells. The immunoproteasome, a version of the proteasome that collaborates with the 11S/PA28 activator to generate immunogenic peptides for presentation by MHC class I molecules, has long been implicated in the onset of the disease, but little is known about immunoproteasome function and regulation in pancreatic ß-cells. Interesting insight into these issues comes from a recent analysis of the immunoproteasome expressed in pancreatic ß-cells during early antiviral defenses mediated by interferon ß (IFNß), a type I IFN implicated in the induction of the diabetic state in human and animal models. Using mouse islets and the MIN6 insulinoma cell line, Freudenburg et al. found that IFNß stimulates expression of the immunoproteasome and the 11S/PA28 activator in a manner fundamentally similar to the classic immuno-inducer IFNγ, with similar timing of mRNA accumulation and decline; similar transcriptional activation mediated primarily by the IRF1 and similar mRNA and protein levels. Furthermore, neither IFNß nor IFNγ altered the expression of regular proteolytic subunits or prevented their incorporation into proteolytic cores. As a result, immunoproteasomes had stochastic combinations of immune and regular proteolytic sites, an arrangement that would likely increase the probability with which unique immunogenic peptides are produced. However, immunoproteasomes were activated by the 11S/PA28 only under conditions of ATP depletion. A mechanism that prevents the activation of immunoproteasome at high ATP levels has not been reported before and could have a major regulatory significance, as it could suppress the generation of immunogenic peptides as cell accumulate immunoproteasome and 11S/PA28, and activate antigen processing only when ATP levels drop. We discuss implications of these new findings on the link between early antiviral response and the onset of type 1 diabetes.

Reversible maleimide-thiol adducts yield glutathione-sensitive poly(ethylene glycol)-heparin hydrogels.

We have recently reported that retro Michael-type addition reactions can be employed for producing labile chemical linkages with tunable sensitivity to physiologically relevant reducing potentials. We reasoned that such strategies would also be useful in the design of glutathione-sensitive hydrogels for a variety of targeted delivery and tissue engineering applications. In this report, we describe hydrogels in which maleimide-functionalized low molecular weight heparin (LMWH) is crosslinked with various thiol-functionalized poly(ethylene glycol) (PEG) multi-arm star polymers. Judicious selection of the chemical identity of the thiol permits tuning of degradation via previously unstudied, but versatile chemical methods. Thiol pKa and hydrophobicity affected both the gelation and degradation of these hydrogels. Maleimide-thiol crosslinking reactions and retro Michael-type addition reactions were verified with 1H NMR during the crosslinking and degradation of hydrogels. PEGs esterified with phenylthiol derivatives, specifically 4-mercaptophenylpropionic acid or 2,2-dimethyl-3-(4-mercaptophenyl)propionic acid, induced sensitivity to glutathione as shown by a decrease in hydrogel degradation time of 4-fold and 5-fold respectively, measured via spectrophotometric quantification of LMWH. The degradation proceeded through the retro Michael-type addition of the succinimide thioether linkage, with apparent pseudo-first order reaction constants derived from oscillatory rheology experiments of 0.039 ± 0.006 h-1 and 0.031 ± 0.003 h-1. The pseudo-first order retro reaction constants were approximately an order of magnitude slower than the degradation rate constants for hydrogels crosslinked via disulfide linkages, indicating the potential use of these Michael-type addition products for reduction-mediated release and/or degradation, with increased blood stability and prolonged drug delivery timescales compared to disulfide moieties.

Electrospinning covalently cross-linking biocompatible hydrogelators.

Many hydrogel materials of interest are homogeneous on the micrometer scale. Electrospinning, the formation of sub-micrometer to micrometer diameter fibers by a jet of fluid formed under an electric field, is one process being explored to create rich microstructures. However, electrospinning a hydrogel system as it reacts requires an understanding of the gelation kinetics and corresponding rheology near the liquid-solid transition. In this study, we correlate the structure of electrospun fibers of a covalently cross-linked hydrogelator with the corresponding gelation transition and kinetics. Polyethylene oxide (PEO) is used as a carrier polymer in a chemically cross-linking poly(ethylene glycol)-high molecular weight heparin (PEG-HMWH) hydrogel. Using measurements of gelation kinetics from multiple particle tracking microrheology (MPT), we correlate the material rheology with the the formation of stable fibers. An equilibrated, cross-linked hydrogel is then spun and the PEO is dissolved. In both cases, microstructural features of the electrospun fibers are retained, confirming the covalent nature of the network. The ability to spin fibers of a cross-linking hydrogel system ultimately enables the engineering of materials and microstructural length scales suitable for biological applications.

Reduction in ATP levels triggers immunoproteasome activation by the 11S (PA28) regulator during early antiviral response mediated by IFNß in mouse pancreatic ß-cells.

Autoimmune destruction of insulin producing pancreatic ß-cells is the hallmark of type I diabetes. One of the key molecules implicated in the disease onset is the immunoproteasome, a protease with multiple proteolytic sites that collaborates with the constitutive 19S and the inducible 11S (PA28) activators to produce immunogenic peptides for presentation by MHC class I molecules. Despite its importance, little is known about the function and regulation of the immunoproteasome in pancreatic ß-cells. Of special interest to immunoproteasome activation in ß-cells are the effects of IFNß, a type I IFN secreted by virus-infected cells and implicated in type I diabetes onset, compared to IFNγ, the classic immunoproteasome inducer secreted by cells of the immune system. By qPCR analysis, we show that mouse insulinoma MIN6 cells and mouse islets accumulate the immune proteolytic ß1(i), ß2(i) and ß5(i), and 11S mRNAs upon exposure to IFNß or IFNγ. Higher concentrations of IFNß than IFNγ are needed for similar expression, but in each case the expression is transient, with maximal mRNA accumulation in 12 hours, and depends primarily on Interferon Regulatory Factor 1. IFNs do not alter expression of regular proteasome genes, and in the time frame of IFNß-mediated response, the immune and regular proteolytic subunits co-exist in the 20S particles. In cell extracts with ATP, these particles have normal peptidase activities and degrade polyubiquitinated proteins with rates typical of the regular proteasome, implicating normal regulation by the 19S activator. However, ATP depletion rapidly stimulates the catalytic rates in a manner consistent with levels of the 11S activator. These findings suggest that stochastic combination of regular and immune proteolytic subunits may increase the probability with which unique immunogenic peptides are produced in pancreatic ß-cells exposed to IFNß, but primarily in cells with reduced ATP levels that stimulate the 11S participation in immunoproteasome function.

In situ crosslinkable heparin-containing poly(ethylene glycol) hydrogels for sustained anticoagulant release.

Low-molecular weight heparin (LMWH) is widely used in anticoagulation therapies and for the prevention of thrombosis. LMWH is administered by subcutaneous injection usually once or twice per day. This frequent and invasive delivery modality leads to compliance issues for individuals on prolonged therapeutic courses, particularly pediatric patients. Here, we report a long-term delivery method for LMWH via subcutaneous injection of long-lasting hydrogels. LMWH is modified with reactive maleimide groups so that it can be crosslinked into continuous networks with four-arm thiolated poly(ethylene glycol) (PEG-SH). Maleimide-modified LMWH (Mal-LMWH) retains bioactivity as indicated by prolonged coagulation time. Hydrogels comprising PEG-SH and Mal-LMWH degrade via hydrolysis, releasing bioactive LMWH by first-order kinetics with little initial burst release. Separately dissolved Mal-LMWH and PEG-SH solutions were co-injected subcutaneously in New Zealand White rabbits. The injected solutions successfully formed hydrogels in situ and released LMWH as measured via chromogenic assays on plasma samples, with accumulation of LMWH occurring at day 2 and rising to near-therapeutic dose equivalency by day 5. These results demonstrate the feasibility of using LMWH-containing, crosslinked hydrogels for sustained and controlled release of anticoagulants.

A role for aberrant protein palmitoylation in FFA-induced ER stress and ß-cell death.

Exposure of insulin-producing cells to elevated levels of the free fatty acid (FFA) palmitate results in the loss of ß-cell function and induction of apoptosis. The induction of endoplasmic reticulum (ER) stress is one mechanism proposed to be responsible for the loss of ß-cell viability in response to palmitate treatment; however, the pathways responsible for the induction of ER stress by palmitate have yet to be determined. Protein palmitoylation is a major posttranslational modification that regulates protein localization, stability, and activity. Defects in, or dysregulation of, protein palmitoylation could be one mechanism by which palmitate may induce ER stress in ß-cells. The purpose of this study was to evaluate the hypothesis that palmitate-induced ER stress and ß-cell toxicity are mediated by excess or aberrant protein palmitoylation. In a concentration-dependent fashion, palmitate treatment of RINm5F cells results in a loss of viability. Similar to palmitate, stearate also induces a concentration-related loss of RINm5F cell viability, while the monounsaturated fatty acids, such as palmoleate and oleate, are not toxic to RINm5F cells. 2-Bromopalmitate (2BrP), a classical inhibitor of protein palmitoylation that has been extensively used as an inhibitor of G protein-coupled receptor signaling, attenuates palmitate-induced RINm5F cell death in a concentration-dependent manner. The protective effects of 2BrP are associated with the inhibition of [(3)H]palmitate incorporation into RINm5F cell protein. Furthermore, 2BrP does not inhibit, but appears to enhance, the oxidation of palmitate. The induction of ER stress in response to palmitate treatment and the activation of caspase activity are attenuated by 2BrP. Consistent with protective effects on insulinoma cells, 2BrP also attenuates the inhibitory actions of prolonged palmitate treatment on insulin secretion by isolated rat islets. These studies support a role for aberrant protein palmitoylation as a mechanism by which palmitate enhances ER stress activation and causes the loss of insulinoma cell viability.

Differential effects of substrate modulus on human vascular endothelial, smooth muscle, and fibroblastic cells.

Regenerative medicine approaches offer attractive alternatives to standard vascular reconstruction; however, the biomaterials to be used must have optimal biochemical and mechanical properties. To evaluate the effects of biomaterial properties on vascular cells, heparinized poly(ethylene glycol) (PEG)-based hydrogels of three different moduli, 13.7, 5.2, and 0.3 kPa, containing fibronectin and growth factor were utilized to support the growth of three human vascular cell types. The cell types exhibited differences in attachment, proliferation, and gene expression profiles associated with the hydrogel modulus. Human vascular smooth muscle cells demonstrated preferential attachment on the highest-modulus hydrogel, adventitial fibroblasts demonstrated preferential growth on the highest-modulus hydrogel, and human umbilical vein endothelial cells demonstrated preferential growth on the lowest-modulus hydrogel investigated. Our studies suggest that the growth of multiple vascular cell types can be supported by PEG hydrogels and that different populations can be controlled by altering the mechanical properties of biomaterials.

Measuring the modulus and reverse percolation transition of a degrading hydrogel.

In light of the growing importance in understanding and controlling the physical cues presented to cells by artificial scaffolds, direct, temporally resolved measurements of the gel modulus are needed. We demonstrate that an interpolation of macro- and microrheology measurements provides a complete history of a hydrogel modulus during degradation through the reverse percolation transition. The latter is identified by microrheology, which captures the critical scaling behavior of reverse percolation, a transition of key importance in controlling cell migration, implant degradation, and tissue regeneration.

Rapid, high resolution screening of biomaterial hydrogelators by µ2rheology.

A combination of sample manipulation and rheological characterization at the microscale is used to identify the gelation of poly(ethylene glycol)-heparin hydrogels over a wide range of compositions. A microfluidic device produces 50-100 droplet samples, each with a different composition. Multiple particle tracking microrheology is used to measure the rheological state of each sample. This combination requires little material and enables efficient and rapid screening of gelation conditions. The high resolution data identifies the gelation reaction percolation boundaries and a lower limit of the total hydrogelator concentration for gelation to occur, which can be used for the subsequent engineering, testing, and processing of these materials.

General and scalable amide bond formation with epimerization-prone substrates using T3P and pyridine.

The mild combination of T3P (n-propanephosphonic acid anhydride) and pyridine has been developed for low-epimerization amide bond formation and implemented for the synthesis of a key intermediate to a glucokinase activator. This robust method is general for the coupling of various racemization-prone acid substrates and amines, including relatively non-nucleophilic anilines, and provides amides in high yields with very low epimerization. With easy reaction setup and product isolation, this protocol offers several practical and experimental benefits.