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1.
J Stroke Cerebrovasc Dis ; 33(6): 107697, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38561168

RESUMO

BACKGROUND AND OBJECTIVES: The field of vascular neurology has undergone significant advances over the last decade, and care has become more complex. However, vascular neurology training programs remain underdeveloped in many countries, despite stroke impact on health care. There are efforts towards building a nationally regulated curricula in some countries. Still, comprehensive planning and implementation of these programs may be needed on a global scale, especially in countries where stroke treatment is not fully implemented. We aim to comprehensively analyze vascular neurology trainees' profiles in Brazil to describe training program contents from trainees and program directors' perspectives. METHODS: We performed an observational, cross-sectional, web-based survey study to describe trainee and program-specific characteristics at vascular neurology fellowship training programs in Brazil. The study was conducted from June to September 2023 using a secure web-based survey sent to active fellows and program directors from all known vascular neurology fellowship programs in the country. All respondents were required to provide informed consent. RESULTS: We obtained a 100 % response rate of a total of 12 programs distributed in 7 federal states. Notably, 57 % of the 28 surveyed fellows were women, 60 % were aged 25-30, and 70 % self-identified as White. All fellows had prior neurology training, and 60 % engaged in the program just following residency. Exposure to various training experiences was favorable, except for simulation-based learning and telestroke training. Program directors perceived exposure to be sufficient for most components but similarly found deficiencies in telestroke and simulation-based learning. Scientific productivity was low, with about two-thirds of fellows having no publications or abstracts. Most fellows (92.6 %) reported performing non-fellowship medical activities to supplement their incomes. DISCUSSION: In conclusion, the number of vascular neurology training programs and trainees in Brazil is currently insufficient and exhibits an uneven geographic distribution. Despite this, the clinical training provided is extensive, and there is generally some funding available for fellows. These insights highlight the need for strategic improvements in Brazil's stroke education and could inform similar developments in other nations.


Assuntos
Currículo , Educação de Pós-Graduação em Medicina , Bolsas de Estudo , Neurologia , Acidente Vascular Cerebral , Humanos , Brasil , Estudos Transversais , Feminino , Acidente Vascular Cerebral/terapia , Acidente Vascular Cerebral/diagnóstico , Masculino , Adulto , Neurologia/educação , Neurologistas/educação , Inquéritos e Questionários , Competência Clínica , Avaliação de Programas e Projetos de Saúde
2.
Plant Biol (Stuttg) ; 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38488200

RESUMO

To investigate how and to what extent there are differences in the photosynthetic plasticity of trees in response to different light environments, six species from three successional groups (late successional, mid-successional, and pioneers) were exposed to three different light environments [deep shade - DS (5% full sunlight - FS), moderate shade - MS (35% FS) and full sunlight - FS]. Maximum net photosynthesis (Amax ), leaf N partitioning, stomatal, mesophile, and biochemical limitations (SL, ML, and BL, respectively), carboxylation velocity (Vcmax ), and electron transport (Jmax ) rates, and the state of photosynthetic induction (IS) were evaluated. Higher values of Amax , Vcmax , and Jmax in FS were observed for pioneer species, which invested the largest amount of leaf N in Rubisco. The lower IS for pioneer species reveals its reduced ability to take advantage of sunflecks. In general, the main photosynthetic limitations are diffusive, with SL and ML having equal importance under FS, and ML decreasing along with irradiance. The leaf traits, which are more determinant of the photosynthetic process, respond independently in relation to the successional group, especially with low light availability. An effective partitioning of leaf N between photosynthetic and structural components played a crucial role in the acclimation process and determined the increase or decrease of photosynthesis in response to the light conditions.

3.
J Am Chem Soc ; 146(9): 6209-6216, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38387466

RESUMO

Chiral aminoalcohols are omnipresent in bioactive compounds. Conventional strategies to access this motif involve multiple-step reactions to install the requisite functionalities stereoselectively using conventional polar bond analysis. This study reveals that a simple chiral oxazolidine-based carboxylic acid can be readily transformed to substituted chiral aminoalcohols with high stereochemical control by Ni-electrocatalytic decarboxylative arylation. This general, robust, and scalable coupling can be used to synthesize a variety of medicinally important compounds, avoiding protecting and functional group manipulations, thereby dramatically simplifying their preparation.

4.
Angew Chem Int Ed Engl ; 63(16): e202319856, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38354272

RESUMO

C-C linked glutarimide-containing structures with direct utility in the preparation of cereblon-based degraders (PROTACs, CELMoDs) can be assessed in a single step from inexpensive, commercial α-bromoglutarimide through a unique Brønsted-acid assisted Ni-electrocatalytic approach. The reaction tolerates a broad array of functional groups that are historically problematic and can be applied to the simplified synthesis of dozens of known compounds that have only been procured through laborious, wasteful, multi-step sequences. The reaction is scalable in both batch and flow and features a trivial procedure wherein the most time-consuming aspect of reaction setup is weighing out the starting materials.


Assuntos
Níquel , Níquel/química , Catálise , Oxirredução
5.
ACS Med Chem Lett ; 15(2): 181-188, 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38352830

RESUMO

We have designed and developed novel and selective TLR7 agonists that exhibited potent receptor activity in a cell-based reporter assay. In vitro, these agonists significantly induced secretion of cytokines IL-6, IL-1ß, IL-10, TNFa, IFNa, and IP-10 in human and mouse whole blood. Pharmacokinetic and pharmacodynamic studies in mice showed a significant secretion of IFNα and TNFα cytokines. When combined with aPD1 in a CT-26 tumor model, the lead compound showed strong synergistic antitumor activity with complete tumor regression in 8/10 mice dosed using the intravenous route. Structure-activity relationship studies enabled by structure-based designs of TLR7 agonists are disclosed.

6.
ACS Med Chem Lett ; 15(2): 189-196, 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38352849

RESUMO

Small molecule toll-like receptor (TLR) 7 agonists have gathered considerable interest as promising therapeutic agents for applications in cancer immunotherapy. Herein, we describe the development and optimization of a series of novel TLR7 agonists through systematic structure-activity relationship studies focusing on modification of the phenylpiperidine side chain. Additional refinement of ADME properties culminated in the discovery of compound 14, which displayed nanomolar reporter assay activity and favorable drug-like properties. Compound 14 demonstrated excellent in vivo pharmacokinetic/pharmacodynamic profiles and synergistic antitumor activity when administered in combination with aPD1 antibody, suggesting opportunities of employing 14 in immuno-oncology therapies with immune checkpoint blockade agents.

7.
Angew Chem Int Ed Engl ; 63(8): e202314617, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38181042

RESUMO

There is a pressing need, particularly in the field of drug discovery, for general methods that will enable direct coupling of tertiary alkyl fragments to (hetero)aryl halides. Herein a uniquely powerful and simple set of conditions for achieving this transformation with unparalleled generality and chemoselectivity is disclosed. This new protocol is placed in context with other recently reported methods, applied to simplify the routes of known bioactive building blocks molecules, and scaled up in both batch and flow. The role of pyridine additive as well as the mechanism of this reaction are interrogated through Cyclic Voltammetry studies, titration experiments, control reactions with Ni(0) and Ni(II)-complexes, and ligand optimization data. Those studies indicate that the formation of a BINAPNi(0) is minimized and the formation of an active pyridine-stabilized Ni(I) species is sustained during the reaction. Our preliminary mechanistic studies ruled out the involvement of Ni(0) species in this electrochemical cross-coupling, which is mediated by Ni(I) species via a Ni(I)-Ni(II)-Ni(III)-Ni(I) catalytic cycle.

8.
Public Health ; 225: 176-181, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37931486

RESUMO

OBJECTIVES: This study aimed to examine changes in the proportion of smokers who were advised to quit smoking by health professionals as part of routine consultations or interactions with their patients between 2008 and 2019. STUDY DESIGN: Serial cross-sectional study. METHODS: Data from two nationally representative cross-sectional surveys were used to examine changes over time in the proportions of smokers who were seen by a doctor or other healthcare provider for any health concern and were advised to quit smoking ('Advice_HP'). An additional dichotomous variable ('AdviceAccess_HP') was created and included smokers who were not seen by a doctor or other healthcare provider in the past 12 months in the 'no advice' received category. Crude and adjusted absolute differences in prevalence rates of smokers who were advised to quit smoking by health professionals as part of routine consultations or interactions with their patients between 2008 and 2019 were evaluated using a generalised linear model. RESULTS: The proportion of smokers who were seen by a health professional for any health concern increased from 58.8% in 2008 to 88.7% in 2019. The proportion of 'AdviceAccess_HP' increased from 33.6% in 2008 to 45.2% in 2019; however, the proportion of 'Advice_HP' decreased from 57.1% in 2008 to 51.0% in 2019. After adjustment for sociodemographic and smoking behaviour characteristics, differences remained virtually unchanged. In 2019, health professionals missed the opportunity to provide around 10 million smokers with brief advice to stop smoking. CONCLUSIONS: Monitoring the actions needed to encourage smoking cessation is critical for achieving the United Nations sustainable development goals. Primary healthcare workers should serve as role models for patients and provide brief advice that increases the likelihood of successfully quitting tobacco use, particularly in low- and middle-income countries.


Assuntos
Abandono do Hábito de Fumar , Humanos , Fumantes , Estudos Transversais , Brasil/epidemiologia , Pessoal de Saúde
9.
Nature ; 623(7988): 745-751, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37788684

RESUMO

Modern retrosynthetic analysis in organic chemistry is based on the principle of polar relationships between functional groups to guide the design of synthetic routes1. This method, termed polar retrosynthetic analysis, assigns partial positive (electrophilic) or negative (nucleophilic) charges to constituent functional groups in complex molecules followed by disconnecting bonds between opposing charges2-4. Although this approach forms the basis of undergraduate curriculum in organic chemistry5 and strategic applications of most synthetic methods6, the implementation often requires a long list of ancillary considerations to mitigate chemoselectivity and oxidation state issues involving protecting groups and precise reaction choreography3,4,7. Here we report a radical-based Ni/Ag-electrocatalytic cross-coupling of substituted carboxylic acids, thereby enabling an intuitive and modular approach to accessing complex molecular architectures. This new method relies on a key silver additive that forms an active Ag nanoparticle-coated electrode surface8,9 in situ along with carefully chosen ligands that modulate the reactivity of Ni. Through judicious choice of conditions and ligands, the cross-couplings can be rendered highly diastereoselective. To demonstrate the simplifying power of these reactions, concise syntheses of 14 natural products and two medicinally relevant molecules were completed.


Assuntos
Produtos Biológicos , Técnicas de Química Sintética , Descarboxilação , Eletroquímica , Eletrodos , Preparações Farmacêuticas , Ácidos Carboxílicos/química , Nanopartículas Metálicas/química , Oxirredução , Prata/química , Produtos Biológicos/síntese química , Produtos Biológicos/química , Níquel/química , Ligantes , Preparações Farmacêuticas/síntese química , Preparações Farmacêuticas/química , Eletroquímica/métodos , Técnicas de Química Sintética/métodos
10.
Acc Chem Res ; 56(20): 2851-2865, 2023 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-37772915

RESUMO

ConspectusTransition-metal catalyzed cross-coupling reactions are fundamental reactions in organic chemistry, facilitating strategic bond formations for accessing natural products, organic materials, agrochemicals, and pharmaceuticals. Redox chemistry enables access to elusive cross-coupling mechanisms through single-electron processes as an alternative to classical two-electron strategies predominated by palladium catalysis. The seminal reports of Baran, MacMillan, Doyle, Molander, Weix, Lin, Fu, Reisman, and others in merging redox perturbation (photochemical, electrochemical, and purely chemical) with catalysis are pivotal to the current resurgence and mechanistic understanding of first-row transition metal-based catalysis. The hallmark of this redox platform is the systematic modulation of transition-metal oxidation states by a photoredox catalyst or at a heterogeneous electrode surface. Electrocatalysis and photocatalysis enhance transition metal catalysis' capacity for bond formation through electron- or energy-transfer processes that promote otherwise challenging elementary steps or elusive mechanisms. Cross-coupling conditions promoted by electrocatalysis and photocatalysis are mild, and bond formation proceeds with exceptionally high chemoselectivity and wide functional group tolerance. The interfacing of abundant first-row transition-metal catalysis with electrocatalysis and photocatalysis has brought about a paradigm shift in cross-coupling technology as practitioners are quickly applying these tools in synthesizing fine chemicals and pharmaceutically relevant motifs. In particular, the merger of Ni catalysis with electro- and photochemistry ushered in a new era for carbon-carbon and carbon-heteroatom cross-couplings with expanded generality compared to their thermally driven counterparts. Over the past decade, we have developed enabling photo- and electrochemical methods throughout our combined research experience in industry (BMS, AstraZeneca) and academia (Professor Baran, Scripps Research) in cross-disciplinary collaborative environments. In this Account, we will outline recent progress from our past and present laboratories in photo- and electrochemically mediated Ni-catalyzed cross-couplings. By highlighting these cross-coupling methodologies, we will also compare mechanistic features of both electro- and photochemical strategies for forging C(sp2)-C(sp3), C(sp3)-C(sp3), C-O, C-N, and C-S bonds. Through these side-by-side comparisons, we hope to demystify the subtle differences between the two complementary tools to enact redox control over transition metal catalysis. Finally, building off the collective experience of ourselves and the rest of the community, we propose a tactical user guide to photo- and electrochemically driven cross-coupling reactions to aid the practitioner in rapidly applying such tools in their synthetic designs.

11.
J Am Chem Soc ; 145(33): 18366-18381, 2023 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-37556344

RESUMO

Triplet-triplet energy transfer (EnT) is a powerful activation pathway in photocatalysis that unlocks new organic transformations and improves the sustainability of organic synthesis. Many current examples, however, still rely on platinum-group metal complexes as photosensitizers, with associated high costs and environmental impacts. Photosensitizers that exhibit thermally activated delayed fluorescence (TADF) are attractive fully organic alternatives in EnT photocatalysis. However, TADF photocatalysts incorporating heavy atoms remain rare, despite their utility in inducing efficient spin-orbit-coupling, intersystem-crossing, and consequently a high triplet population. Here, we describe the synthesis of imidazo-phenothiazine (IPTZ), a sulfur-containing heterocycle with a locked planar structure and a shallow LUMO level. This acceptor is used to prepare seven TADF-active photocatalysts with triplet energies up to 63.9 kcal mol-1. We show that sulfur incorporation improves spin-orbit coupling and increases triplet lifetimes up to 3.64 ms, while also allowing for tuning of photophysical properties via oxidation at the sulfur atom. These IPTZ materials are applied as photocatalysts in five seminal EnT reactions: [2 + 2] cycloaddition, the disulfide-ene reaction, and Ni-mediated C-O and C-N cross-coupling to afford etherification, esterification, and amination products, outcompeting the industry-standard TADF photocatalyst 2CzPN in four of the five studied scenarios. Detailed photophysical and theoretical studies are used to understand structure-activity relationships and to demonstrate the key role of the heavy atom effect in the design of TADF materials with superior photocatalytic performance.

12.
J Am Chem Soc ; 145(28): 15088-15093, 2023 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-37399078

RESUMO

The first practical, fully stereoselective P(V)-radical hydrophosphorylation is presented herein by using simple, limonene-derived reagent systems. A set of reagents have been developed that upon radical initiation react smoothly with olefins and other radical acceptors to generate P-chiral products, which can be further diversified (with conventional 2e- chemistry) to a range of underexplored bioisosteric building blocks. The reactions have a wide scope with excellent chemoselectivity, and the unexpected stereochemical outcome has been supported computationally and experimentally. Initial ADME studies are suggestive of the promising properties of this rarely explored chemical space.

13.
J Intensive Care Med ; 38(7): 657-667, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36803155

RESUMO

Introduction: Critical care survivors sustain a variety of sequelae after intensive care medicine (ICM) admission, and the Coronavirus Disease 2019 (COVID-19) pandemic has added further challenges. Specifically, ICM memories play a significant role, and delusional memories are associated with poor outcomes post-discharge including a delayed return to work and sleep problems. Deep sedation has been associated with a greater risk of perceiving delusional memories, bringing a move toward lighter sedation. However, there are limited reports on post-ICM memories in COVID-19, and influence of deep sedation has not been fully defined. Therefore, we aimed to evaluate ICM-memory recall in COVID-19 survivors and their relation with deep sedation. Materials/Methods: Adult COVID-19 ICM survivors admitted to a Portuguese University Hospital between October 2020 and April 2021 (second/third "waves") were evaluated 1 to 2 months post-discharge using "ICU Memory Tool," to assess real, emotional, and delusional memories. Results: The study included 132 patients (67% male; median age = 62 years, Acute Physiology and Chronic Health Evaluation [APACHE]-II = 15, Simplified Acute Physiology Score [SAPS]-II = 35, ICM stay = 9 days). Approximately 42% received deep sedation (median duration = 19 days). Most participants reported real (87%) and emotional (77%) recalls, with lesser delusional memories (36.4%). Deeply sedated patients reported significantly fewer real memories (78.6% vs 93.4%, P = .012) and increased delusional memories (60.7% vs 18.4%, P < .001), with no difference in emotional memories (75% vs 80.4%, P = .468). In multivariate analysis, deep sedation had a significant, independent association with delusional memories, increasing their likelihood by a factor of approximately 6 (OR = 6.274; 95% confidence interval = 1.165-33.773, P = .032), without influencing real (P = .545) or emotional (P = .133) memories. Conclusions: This study contributes to a better understanding of the potential adverse effects of deep sedation on ICM memories in critical COVID-19 survivors, indicating a significant, independent association with the incidence of delusional recalls. Although further studies are needed to support these findings, they suggest that strategies targeted to minimize sedation should be favored, aiming to improve long-term recovery.


Assuntos
COVID-19 , Sedação Profunda , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , Feminino , Unidades de Terapia Intensiva , Sedação Profunda/psicologia , Assistência ao Convalescente , Alta do Paciente , Cuidados Críticos/psicologia , Sobreviventes/psicologia
14.
NPJ Prim Care Respir Med ; 32(1): 55, 2022 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-36513683

RESUMO

In Brazil, prevalence of diagnosed COPD among adults aged 40 years and over is 16% although over 70% of cases remain undiagnosed. Hypertension is common and well-recorded in primary care, and frequently co-exists with COPD because of common causes such as tobacco smoking, therefore we conducted a cross-sectional screening test accuracy study in nine Basic Health Units in Brazil, among hypertensive patients aged ≥40 years to identify the optimum screening test/combinations to detect undiagnosed COPD. We compared six index tests (four screening questionnaires, microspirometer and peak flow) against the reference test defined as those below the lower limit of normal (LLN-GLI) on quality diagnostic spirometry, with confirmed COPD at clinical review. Of 1162 participants, 6.8% (n = 79) had clinically confirmed COPD. Peak flow had a higher specificity but lower sensitivity than microspirometry (sensitivity 44.3% [95% CI 33.1, 55.9], specificity 95.5% [95% CI 94.1, 96.6]). SBQ performed well compared to the other questionnaires (sensitivity 75.9% [95% CI 65.0, 84.9], specificity 59.2% [95% CI 56.2, 62.1]). A strategy requiring both SBQ and peak flow to be positive yielded sensitivity of 39.2% (95% CI 28.4, 50.9) and specificity of 97.0% (95% CI 95.7, 97.9). The use of simple screening tests was feasible within the Brazilian primary care setting. The combination of SBQ and peak flow appeared most efficient, when considering performance of the test, cost and ease of use (costing £1690 (5554 R$) with 26.7 cases detected per 1,000 patients). However, the choice of screening tests depends on the clinical setting and availability of resources.ISRCTN registration number: 11377960.


Assuntos
Hipertensão , Doença Pulmonar Obstrutiva Crônica , Adulto , Humanos , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Brasil , Estudos Transversais , Análise Custo-Benefício , Espirometria , Inquéritos e Questionários , Hipertensão/diagnóstico , Hipertensão/epidemiologia , Hipertensão/complicações , Programas de Rastreamento
15.
J Am Chem Soc ; 144(38): 17709-17720, 2022 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-36106767

RESUMO

A useful protocol for achieving decarboxylative cross-coupling (DCC) of redox-active esters (RAE, isolated or generated in situ) and halo(hetero)arenes is reported. This pragmatically focused study employs a unique Ag-Ni electrocatalytic platform to overcome numerous limitations that have plagued this strategically powerful transformation. In its optimized form, coupling partners can be combined in a surprisingly simple way: open to the air, using technical-grade solvents, an inexpensive ligand and Ni source, and substoichiometric AgNO3, proceeding at room temperature with a simple commercial potentiostat. Most importantly, all of the results are placed into context by benchmarking with state-of-the-art methods. Applications are presented that simplify synthesis and rapidly enable access to challenging chemical space. Finally, adaptation to multiple scale regimes, ranging from parallel milligram-based synthesis to decagram recirculating flow is presented.


Assuntos
Ésteres , Catálise , Ligantes , Oxirredução , Solventes
16.
Braz J Biol ; 84: e256691, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35544787

RESUMO

microRNAs (miRNAs) are recognized as diabetes mellitus type 2 (T2DM) biomarkers useful for disease metabolism comprehension and have great potential as therapeutics targets. BDNF and IGF1 increased expression are highly involved in the benefits of insulin and glucose paths, however, they are down-regulated in insulin resistance conditions, while their expression increase is correlated to the improvement of glucose and insulin metabolism. Studies suggest the microRNA regulation of these genes in several different contexts, providing a novel investigation approach for comprehending T2DM metabolism and revealing potential therapeutic targets. In the present study, we investigate in different animal models (human, rat, and mouse) miRNAs that target BDNF and IGF1 in skeletal muscle tissue with T2DM physiological conditions. Bioinformatics tools and databases were used to miRNA prediction, molecular homology, experimental validation of interactions, expression in the studied physiological condition, and network interaction. The findings showed three miRNAs candidates for IGF1(miR-29a, miR-29b, and miR-29c) and one for BDNF (miR-206). The experimental evaluations and the search for the expression in skeletal muscle from T2DM subjects confirmed the predicted interaction between miRNA-mRNA for miR-29b and miR-206 through human, rat, and mouse models. This interaction was reaffirmed in multiple network analyses. In conclusion, our results show the regulation relationship between miR-29b and miR-206 with the investigated genes, in several tissues, suggesting an inhibition pattern. Nevertheless, these data show a large number of possible interaction physiological processes, for future biotechnological prospects.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Insulinas , MicroRNAs , Animais , Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/uso terapêutico , Biologia Computacional , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Glucose/uso terapêutico , Humanos , Resistência à Insulina/genética , Fator de Crescimento Insulin-Like I/genética , Fator de Crescimento Insulin-Like I/uso terapêutico , Insulinas/uso terapêutico , Camundongos , MicroRNAs/genética , MicroRNAs/metabolismo , MicroRNAs/uso terapêutico , Ratos
17.
Colloids Surf B Biointerfaces ; 216: 112512, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35533561

RESUMO

In this study, we have directly incorporated nanographene oxide (nGO) into a hydrophobic drug for enhanced dissolution performance through an antisolvent technique. Apixaban (APX) drug composites were synthesized with nGO incorporation ranging from 0.8% to 2.0% concentration. It was observed that the nGO was successfully embedded without any changes to the original drug crystal structure or physical properties. Dissolution of the drug composites was evaluated using US Pharmacopeia Paddle Method (USP 42). The time needed to reach a 50% release (T50) reduced from 106 min to 24 min with the integration of 1.96% nGO in APX and the T80 also dropped accordingly. Alternatively, dissolution rate showed promising performance with increase in nGO concentration. Initial dissolution rate increased dramatically from 74 µg/min to 540 µg/min. Further, work done in intestinal media revealed T50 went from not dissolving to 79.0 min. Decreased lipophilicity or logP value and increased aqueous solubility are both accredited to hydrophilic nGO water dispersion, producing a hydrophilic channel into the drug crystal surfaces through intermolecular interaction. Additionally, physical, and chemical characterizations confirm that hydrophobic apixaban was successfully transformed into a hydrophilic composite, showing potential for this technology to improve dissolution rate of a model hydrophobic compound.


Assuntos
Grafite , Pirazóis , Piridonas , Grafite/química , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas , Óxidos , Pirazóis/química , Piridonas/química , Solubilidade , Água/química
18.
Nature ; 606(7913): 313-318, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35381598

RESUMO

Cross-coupling between two similar or identical functional groups to form a new C-C bond is a powerful tool to rapidly assemble complex molecules from readily available building units, as seen with olefin cross-metathesis or various types of cross-electrophile coupling1,2. The Kolbe electrolysis involves the oxidative electrochemical decarboxylation of alkyl carboxylic acids to their corresponding radical species followed by recombination to generate a new C-C bond3-12. As one of the oldest known Csp3-Csp3 bond-forming reactions, it holds incredible promise for organic synthesis, yet its use has been almost non-existent. From the perspective of synthesis design, this transformation could allow one to agnostically execute syntheses without regard to polarity or neighbouring functionality just by coupling ubiquitous carboxylates13. In practice, this promise is undermined by the strongly oxidative electrolytic protocol used traditionally since the nineteenth century5, thereby severely limiting its scope. Here, we show how a mildly reductive Ni-electrocatalytic system can couple two different carboxylates by means of in situ generated redox-active esters, termed doubly decarboxylative cross-coupling. This operationally simple method can be used to heterocouple primary, secondary and even certain tertiary redox-active esters, thereby opening up a powerful new approach for synthesis. The reaction, which cannot be mimicked using stoichiometric metal reductants or photochemical conditions, tolerates a range of functional groups, is scalable and is used for the synthesis of 32 known compounds, reducing overall step counts by 73%.


Assuntos
Ácidos Carboxílicos , Técnicas de Química Sintética , Níquel , Ácidos Carboxílicos/química , Catálise , Descarboxilação , Eletroquímica , Ésteres/química , Estrutura Molecular , Níquel/química , Oxirredução
19.
Chem Sci ; 13(8): 2296-2302, 2022 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-35310486

RESUMO

Energy transfer (EnT) is a fundamental activation process in visible-light-promoted photocycloaddition reactions. This work describes the performance of imidazoacridine-based TADF materials for visible-light mediated triplet-triplet EnT photocatalysis. The TADF material ACR-IMAC has been discovered as an inexpensive, high-performance organic alternative to the commonly used metal-based photosensitizers for visible-light EnT photocatalysis. The efficiency of ACR-IMAC as a photosensitizer is comparable with Ir-based photosensitizers in both intra- and intermolecular [2 + 2] cycloadditions. ACR-IMAC mediated both dearomative and non-dearomative [2 + 2] cycloadditions in good yields, with high regio- and diastereocontrol. Cyclobutane-containing bi- tri- and tetracylic scaffolds were successfully prepared, with broad tolerance toward functional groups relevant to drug discovery campaigns. Fluorescence quenching experiments, time-correlated single-photon counting, and transient absorption spectroscopy were also conducted to provide insight into the reaction and evidence for an EnT mechanism.

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