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Saturated hydrocarbon bonds are ubiquitous in organic molecules; to date, the selective functionalization of C(sp3)-H bonds continues to pose a notorious difficulty, thereby garnering significant attention from the synthetic chemistry community. During the past several decades, a wide array of powerful new methodologies has been developed to enantioselectively modify C(sp3)-H bonds that is successfully applied in asymmetric formation of diverse bonds, including C-C, C-N, and C-O bonds; nevertheless, the asymmetric C(sp3)-H alkylation is elusive and, therefore, far less explored. In this work, we report a direct and robust strategy to construct highly valuable enantioenriched unnatural α-amino acid (α-AA) cognates and peptides by a copper-catalyzed enantioselective remote C(sp3)-H alkylation of N-fluorocarboxamides and readily accessible glycine esters under ambient conditions. The key to success lies in the optically active Cu catalyst generated through the coordination of glycine derivatives to enantiopure bisphosphine/Cu(I) species, which is beneficial to the single electronic reduction of N-fluorocarboxamides and the subsequent stereodetermining alkylation. More importantly, all types (primary, secondary, tertiary, and even α-oxy) of δ-C(sp3)-H bonds could be site- and stereospecifically activated by the kinetically favored 1,5-hydrogen atom transfer (1,5-HAT) step.
Assuntos
Cobre , Glicina , Cobre/química , Alquilação , Peptídeos/química , CatáliseRESUMO
Covering: up to 2023Huperzine alkaloids are a group of natural products belonging to the Lycopodium alkaloids family. The representative member huperzine A has a unique structure and exhibits potent inhibitory activity against acetylcholine esterase (AChE). This subfamily of alkaloids provides a great opportunity for developing synthetic methodologies and asymmetric synthesis. The efforts towards the synthesis of huperzine A have cultivated dozens of total syntheses and a rich body of new chemistry. Impressive progress has also been made in the synthesis of other huperzine alkaloids. The total syntheses of huperzines B, U, O, Q and R, structure reassignment and total syntheses of huperzines K, M and N have been reported in the past decade. This review focuses on the synthetic organic chemistry and the biosynthesis and medicinal chemistry of huperzines are also covered briefly.
Assuntos
Alcaloides , Lycopodium , Sesquiterpenos , Estrutura Molecular , Lycopodium/química , Alcaloides/química , Sesquiterpenos/químicaRESUMO
Covering: 2006 to 2023(-)-Galantamine is a natural product with distinctive structural features and potent inhibitory activity against acetylcholine esterase (AChE). It is clinically approved for the treatment of Alzheimer's disease. The clinical significance and scarcity of this natural product have prompted extensive and ongoing efforts towards the chemical synthesis of this challenging tetracyclic structure. The objective of this review is to summarize and discuss recent progress in the total synthesis of galantamine from 2006 to 2023. The contents are organized according to the synthetic strategies for the construction of the quaternary center. Key features of each synthesis have been highlighted, followed by a summary and outlook at the end.
Assuntos
Doença de Alzheimer , Produtos Biológicos , Inibidores da Colinesterase , Galantamina , Galantamina/síntese química , Galantamina/farmacologia , Galantamina/uso terapêutico , Galantamina/química , Doença de Alzheimer/tratamento farmacológico , Produtos Biológicos/farmacologia , Produtos Biológicos/síntese química , Produtos Biológicos/química , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/farmacologia , Inibidores da Colinesterase/uso terapêutico , Inibidores da Colinesterase/química , Estrutura Molecular , HumanosRESUMO
A novel method is described for the synthesis of 2,4-disubstituted oxazole and thiazole derivates via the coupling of α-diazoketones with (thio)amides or thioureas using trifluoromethanesulfonic acid (TfOH) as a catalyst. This protocol is characterized by mild reaction conditions, metal-free, and simplicity and also features good functional group tolerance, good to excellent yields, and a broad substrate scope with more than 40 examples. Experimental studies suggest a mechanism involving 2-oxo-2-phenylethyl trifluoromethanesulfonate as the key intermediate.
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A palladium-catalyzed decarboxylative asymmetric [4 + 2] annulation of methyleneindolinones with a zwitterionic oxo-1,4-dipole intermediate was successfully developed to access spirocyclic oxindoles bearing two vicinal stereocenters in good yields with high diastereoselectivities and enantioselectivities. This strategy features a broad substrate scope (28 examples), allowing for efficient scale-up. Further selective transformation of the product and preliminary mechanistic studies were conducted.
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Mainly owing to their well-defined pore structures and high surface areas, metal-organic frameworks (MOFs) have recently become a versatile class of materials for enzyme immobilization. Nevertheless, most previous studies were focused on model enzymes such as cytochrome c, catalase, and glucose oxidase, with the application of MOF-derived biocomposites for (asymmetric) organic synthesis being rare. In the present work, the immobilization of the ketoreductase KmCR2 onto the zeolitic imidazolate framework (ZIF), a prominent type of MOF, was pursued using the controlled co-precipitation strategy, with a low 2-methylimidazole (2-mIM)/Zn molar ratio of 8 : 1 being employed. Such fabricated biocomposites denoted as KmCR2@ZIF were found to exist mainly in an amorphous phase, as suggested by the scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD) data. Improved thermal and storage stabilities were observed for KmCR2@ZIF compared with the free enzyme. Stereoselective reduction of nine diarylmethanones 1 catalyzed by KmCR2@ZIF was performed, and the corresponding enantioenriched diarylmethanols 2 were afforded in 40-92% conversions with good to excellent optical purities (up to >99% ee). Critically, the current work demonstrated that the unique characteristic of KmCR2, namely the substituent position-controlled stereospecificity (meta versus para or ortho), was not altered upon the enzyme immobilization onto the ZIF.
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Marine natural products continue to hold great promise as potential candidates for the discovery of anti-inflammatory drug. In our previous investigation, we successfully synthesized axinelline A, a naturally occurring cyclooxygenase-2 (COX-2) inhibitor, as a promising anti-inflammatory lead compound. This study was to discover novel COX inhibitors with balanced inhibition, aiming to mitigate the severe adverse effects through further structural modification of axinelline A. Of the synthetic derivatives, compound 5e showed highest COX-2 inhibitory activity and balanced COX inhibition (IC50 = 1.74 µM; selectivity ((IC50 (COX-1)/IC50(COX-2) = 16.32). The in vitro anti-inflammatory results indicated that 5e effectively suppressed the expression of pro-inflammatory mediators via the NF-κB signaling pathway rather than the MAPK signaling pathway. The in vivo ulcerative colitis assay demonstrated 5e significantly ameliorated the histological damages and showed strong protection against DSS-induced acute colitis. Therefore, our findings suggest that compound 5e exhibits potential as a promising anti-inflammatory agent with attenuated colitis-related adverse effects.
Assuntos
Catecóis , Colite , Humanos , Ciclo-Oxigenase 2/metabolismo , Colite/induzido quimicamente , Colite/tratamento farmacológico , NF-kappa B/metabolismo , Anti-Inflamatórios/efeitos adversos , Anti-Inflamatórios não Esteroides/uso terapêutico , Inibidores de Ciclo-Oxigenase 2/farmacologiaRESUMO
In pursuit of enhancing the anti-resistance efficacy and solubility of our previously identified NNRTI 1, a series of biphenyl-quinazoline derivatives were synthesized employing a structure-based drug design strategy. Noteworthy advancements in anti-resistance efficacy were discerned among some of these analogs, prominently exemplified by compound 7ag, which exhibited a remarkable 1.37 to 602.41-fold increase in potency against mutant strains (Y181C, L100I, Y188L, F227L + V106A, and K103N + Y181C) in comparison to compound 1. Compound 7ag also demonstrated comparable anti-HIV activity against both WT HIV and K103N, albeit with a marginal reduction in activity against E138K. Of significance, this analog showed augmented selectivity index (SI > 5368) relative to compound 1 (SI > 37764), Nevirapine (SI > 158), Efavirenz (SI > 269), and Etravirine (SI > 1519). Moreover, it displayed a significant enhancement in water solubility, surpassing that of compound 1, Etravirine, and Rilpivirine. To elucidate the underlying molecular mechanisms, molecular docking studies were undertaken to probe the critical interactions between 7ag and both WT and mutant strains of HIV-1 RT. These findings furnish invaluable insights driving further advancements in the development of DAPYs for HIV therapy.
Assuntos
Fármacos Anti-HIV , Compostos de Bifenilo , Desenho de Fármacos , Transcriptase Reversa do HIV , HIV-1 , Quinazolinas , Inibidores da Transcriptase Reversa , Solubilidade , Humanos , Fármacos Anti-HIV/farmacologia , Fármacos Anti-HIV/química , Fármacos Anti-HIV/síntese química , Compostos de Bifenilo/antagonistas & inibidores , Compostos de Bifenilo/farmacologia , Compostos de Bifenilo/química , Relação Dose-Resposta a Droga , Farmacorresistência Viral/efeitos dos fármacos , Transcriptase Reversa do HIV/antagonistas & inibidores , Transcriptase Reversa do HIV/metabolismo , HIV-1/efeitos dos fármacos , HIV-1/enzimologia , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Quinazolinas/farmacologia , Quinazolinas/química , Quinazolinas/síntese química , Inibidores da Transcriptase Reversa/farmacologia , Inibidores da Transcriptase Reversa/química , Inibidores da Transcriptase Reversa/síntese química , Relação Estrutura-AtividadeRESUMO
It is reported that panaxadiol has neuroprotective effects. Previous studies have found that compound with carbamate structure introduced at the 3-OH position of 20 (R) -panaxadiol showed the most effective neuroprotective activity with an EC50 of 13.17⯵M. Therefore, we designed and synthesized a series of ginseng diol carbamate derivatives with ginseng diol as the lead compound, and tested their anti-AD activity. It was found that the protective effect of compound Q4 on adrenal pheochromocytoma was 80.6⯱â¯10.85â¯% (15⯵M), and the EC50 was 4.32⯵M. According to the ELISA results, Q4 reduced the expression of Aß25-35 by decreasing ß-secretase production. Molecular docking studies revealed that the binding affinity of Q4 to ß-secretase was -49.67â¯kcal/mol, indicating a strong binding affinity of Q4 to ß-secretase. Western blotting showed that compound Q4 decreased IL-1ß levels, which may contribute to its anti-inflammatory effect. Furthermore, compound Q4 exhibits anti-AD activities by reducing abnormal phosphorylation of tau protein and activation of the mitogen activated protein kinase pathway. The learning and memory deficits in mice treated with Q4in vivo were significantly alleviated. Therefore, Q4 may be a promising multifunctional drug for the treatment of AD, providing a new way for anti-AD drugs.
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Doença de Alzheimer , Ginsenosídeos , Fármacos Neuroprotetores , Camundongos , Animais , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Simulação de Acoplamento Molecular , Carbamatos/química , Secretases da Proteína Precursora do Amiloide/metabolismo , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêuticoRESUMO
Targeting Ribonuclease H (RNase H) has been considered a viable strategy for HIV therapy. In this study, a series of novel thiazolo[3, 2-a]pyrimidine derivatives were firstly designed and synthesized as potential inhibitors of HIV-1 RNase H. Among these compounds, A28 exhibited the most potent inhibition against HIV-1 RNase H with an IC50 value of 4.14 µM, which was about 5-fold increase in potency than the hit compound A1 (IC50 = 21.49 µM). To gain deeper insights into the structure-activity relationship (SAR), a CoMFA model was constructed to yield reasonable statistical results (q2 = 0.658 and R2 = 0.969). Results from magnesium ion chelation experiments and molecular docking studies revealed that these thiazolopyrimidine inhibitors may exert their inhibitory activity by binding to an allosteric site on RNase H at the interface between subunits p51 and p66. Furthermore, this analog demonstrated favorable physicochemical properties. Our findings provide valuable groundwork for further development of allosteric inhibitors targeting HIV-1 RNase H.
Assuntos
Desenho de Fármacos , HIV-1 , Simulação de Acoplamento Molecular , Pirimidinas , Relação Estrutura-Atividade , Pirimidinas/química , Pirimidinas/farmacologia , Pirimidinas/síntese química , HIV-1/efeitos dos fármacos , HIV-1/enzimologia , Humanos , Tiazóis/química , Tiazóis/farmacologia , Tiazóis/síntese química , Estrutura Molecular , Fármacos Anti-HIV/farmacologia , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/química , Ribonuclease H/antagonistas & inibidores , Ribonuclease H/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Ribonuclease H do Vírus da Imunodeficiência Humana/antagonistas & inibidores , Ribonuclease H do Vírus da Imunodeficiência Humana/metabolismoRESUMO
Hydroformylation of olefins is widely used in the chemical industry due to its versatility and the ability to produce valuable aldehydes with 100% atom economy. Herein, a hybrid phosphate promoter was found to efficiently promote rhodium-catalyzed hydroformylation of styrenes under remarkably mild conditions with high regioselectivities. Preliminary mechanistic studies revealed that the weak coordination between the Rhodium and the P=O double bond of this pentavalent phosphate likely induced exceptional reactivity and high ratios of branched aldehydes to linear products.
RESUMO
Ribonuclease H (RNase H) was identified as an important target for HIV therapy. Currently, no RNase H inhibitors have reached clinical status. Herein, a series of novel thiazolone[3,2-a]pyrimidine-containing RNase H inhibitors were developed, based on the hit compound 10i, identified from screening our in-house compound library. Some of these derivatives exhibited low micromolar inhibitory activity. Among them, compound 12b was identified as the most potent inhibitor of RNase H (IC50 = 2.98 µM). The experiment of magnesium ion coordination was performed to verify that this ligand could coordinate with magnesium ions, indicating its binding ability to the catalytic site of RNase H. Docking studies revealed the main interactions of this ligand with RNase H. A quantitative structure activity relationship (QSAR) was also conducted to disclose several predictive mathematic models. A molecular dynamics simulation was also conducted to determine the stability of the complex. Taken together, thiazolone[3,2-a]pyrimidine can be regarded as a potential scaffold for the further development of RNase H inhibitors.
Assuntos
Fármacos Anti-HIV , Simulação de Acoplamento Molecular , Pirimidinas , Relação Quantitativa Estrutura-Atividade , Pirimidinas/química , Pirimidinas/farmacologia , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Fármacos Anti-HIV/síntese química , Humanos , Simulação de Dinâmica Molecular , Ribonuclease H/antagonistas & inibidores , Ribonuclease H/metabolismo , Desenho de Fármacos , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , HIV-1/enzimologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Tiazóis/química , Tiazóis/farmacologia , Estrutura MolecularRESUMO
16ß-Methylcorticoids are among the most important glucocorticoid steroids for the treatment of various dermatological disorders, respiratory infections, and other allergic reactions elicited during inflammatory responses of the human body. Betamethasone dipropionate, clobetasol propionate, and beclomethasone dipropionate are particularly noteworthy for their synthetic intractability. Despite five decades of research, these 16ß-methylcorticoids have remained challenging synthetic targets owing to insurmountable issues of reactivity, selectivity, and cost efficiency associated with all previously explored strategies. We herein report our practicability-oriented strategy toward the unified stereoselective synthesis of 16ß-methylcorticoids in 12.6-14.0 % overall yield from commercially available 9α-hydroxyandrost-4-ene-3,17-dione (9α-OH-AD). In this approach, the chiral C16ß-Me and C17α-OH groups of the corticosteroid D ring were installed via a substrate-controlled diastereo- and enantioselective Mn-catalyzed oxidation-reduction hydration of Δ4,9(11),16 -triene-3,20-dione. The C1-C2 double bond of the corticosteroid A ring was constructed using an unprecedented engineered 3-ketosteroid-Δ1 -dehydrogenase (MK4-KstD)-catalyzed regioselective Δ1 -dehydrogenation of Δ4,9(11) -diene-3,21-dione. This strategy provides a general method and a key precursor for the divergent synthesis of a variety of glucocorticoids and related steroidal drugs.
Assuntos
Beclometasona , Clobetasol , Humanos , Clobetasol/uso terapêutico , Betametasona/uso terapêutico , Esteroides , CorticosteroidesRESUMO
This paper describes a concise, asymmetric and stereodivergent total synthesis of tacaman alkaloids. A key step in this synthesis is the biocatalytic Baeyer-Villiger oxidation of cyclohexanone, which was developed to produce seven-membered lactones and establish the required stereochemistry at the C14 position (92 % yield, 99 % ee, 500â mg scale). Cis- and trans-tetracyclic indoloquinolizidine scaffolds were rapidly synthesized through an acid-triggered, tunable acyl-Pictet-Spengler type cyclization cascade, serving as the pivotal reaction for building the alkaloid skeleton. Computational results revealed that hydrogen bonding was crucial in stabilizing intermediates and inducing different addition reactions during the acyl-Pictet-Spengler cyclization cascade. By strategically using these two reactions and the late-stage diversification of the functionalized indoloquinolizidine core, the asymmetric total syntheses of eight tacaman alkaloids were achieved. This study may potentially advance research related to the medicinal chemistry of tacaman alkaloids.
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Previous N-glycosylation approaches have predominately involved acidic conditions, facing challenges of low stereoselectivity and limited scope. Herein, we introduce a radical activation strategy that enables versatile and stereoselective N-glycosylation using readily accessible glycosyl sulfinate donors under basic conditions and exhibits exceptional tolerance towards various N-aglycones containing alkyl, aryl, heteroaryl and nucleobase functionalities. Preliminary mechanistic studies indicate a pivotal role of iodide, which orchestrates the formation of a glycosyl radical from the glycosyl sulfinate and subsequent generation of the key intermediate, a configurationally well-defined glycosyl iodide, which is subsequently attacked by an N-aglycone in a stereospecific SN2 manner to give the desired N-glycosides. An alternative route involving the coupling of a glycosyl radical and a nitrogen-centered radical is also proposed, affording the exclusive 1,2-trans product. This novel approach promises to broaden the synthetic landscape of N-glycosides, offering a powerful tool for the construction of complex glycosidic structures under mild conditions.
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Darobactin is a heptapeptide antibiotic featuring an ether cross-link and a C-C cross-link, and both cross-links are installed by a radical S-adenosylmethionine (rSAM) enzyme DarE. How a single DarE enzyme affords the two chemically distinct cross-links remains largely obscure. Herein, by mapping the biosynthetic landscape for darobactin-like RiPP (daropeptide), we identified and characterized two novel daropeptides that lack the C-C cross-link present in darobactin and instead are solely composed of ether cross-links. Phylogenetic and mutagenesis analyses reveal that the daropeptide maturases possess intrinsic multifunctionality, catalyzing not only the formation of ether cross-link but also C-C cross-linking and Ser oxidation. Intriguingly, the different chemical outcomes are controlled by the exact substrate motifs. Our work not only provides a roadmap for the discovery of new daropeptide natural products but also offers insights into the regulatory mechanisms that govern these remarkably versatile ether cross-link-forming rSAM enzymes.
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Éter , S-Adenosilmetionina , S-Adenosilmetionina/química , Filogenia , Éteres , Etil-Éteres , CatáliseRESUMO
Herein, we present a novel and ecofriendly biocatalytic approach for synthesizing efinaconazole (7), a clinically used antifungal agent. This method involves utilizing benzaldehyde lyase (BAL) to catalyze the crucial benzoin condensation step in the ketone precursor. Treating 2,4-difluorobenzaldehyde with BAL in the presence of thiamin-diphosphate (ThDP) and Mg2+ resulted in the formation of α-hydroxy ketone which then underwent the preparation of 7. This innovative approach not only provides a greener alternative but also offers significant advantages over the traditional chemical process. Through our efforts and development work, we have established efficient and scalable procedures that enable the production of 7 in a moderate 38% yield.
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Tiamina Pirofosfato , Triazóis , Benzoína , CetonasRESUMO
A method for the syntheses of substituted α,ß-unsaturated δ-lactams (2) from the commercially available compound N-Boc-2,4-dioxopiperidine (1) has been developed. The α-substituents were introduced by a reductive Knoevenagel condensation reaction, and the ß-substituents were installed by palladium-catalyzed cross coupling reactions. More than 20 diverse examples were prepared in 2-3 steps. The synthesis was operationally simple, user-friendly, and easy to scale up.
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The organocatalytic asymmetric Morita-Baylis-Hillman (MBH) reaction of isatin derivatives with various vinyl sulfones is disclosed. Chiral sulfone-containing 3-hydroxyoxindoles were produced in good to high yields and with good to high ee's. This report displays an unprecedented example to apply activated alkenes with sulfone moiety other than carbonyl groups in asymmetric MBH reactions and provides an efficient strategy to incorporate the sulfone functional group for the synthesis of chiral 3-hydroxyoxindoles.
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We have developed a method for highly regioselective S-H bond insertion reactions of various diazo compounds and cyclic thioamide derivatives at room temperature. These reactions provide straightforward access to alkylated benzimidazoles, benzothiazoles, and benzoxazoles. This mild method uses readily available TfOH as a catalyst and features a broad substrate scope, good functional group tolerance, good to excellent yields, and high regioselectivities.