Pyridin-2(1H)-ones: a promising class of HIV-1 non-nucleoside reverse transcriptase inhibitors

Regioselective [2 + 1] photocycloaddition of 2-pyridones with diazo compounds

Herein, we report a novel regioselective [2 + 1] cyclization reaction of 2-pyridones with carbenes generated in situ via visible light irradiation, without the requirement for catalysts or additives. The diverse functional groups of 2-pyridones and diazo compounds exhibit good tolerance, enabling the rapid synthesis of highly valuable cyclopropanated dihydro-2-pyridone scaffolds with exceptional regio- and stereoselectivity. Furthermore, DFT calculations provide a comprehensive explanation for the regio- and stereoselectivity observed in the reaction.

Diversity-oriented functionalization of 2-pyridones and uracils

Heterocycles 2-pyridone and uracil are privileged pharmacophores. Diversity-oriented synthesis of their derivatives is in urgent need in medicinal chemistry. Herein, we report a palladium/norbornene cooperative catalysis enabled dual-functionalization of iodinated 2-pyridones and uracils. The success of this research depends on the use of two unique norbornene derivatives as the mediator. Readily available alkyl halides/tosylates and aryl bromides are utilized as ortho-alkylating and -arylating reagents, respectively. Widely accessible ipso-terminating reagents, including H/DCO2Na, boronic acid/ester, terminal alkene and alkyne are compatible with this protocol. Thus, a large number of valuable 2-pyridone derivatives, including deuterium/CD3-labeled 2-pyridones, bicyclic 2-pyridones, 2-pyridone-fenofibrate conjugate, axially chiral 2-pyridone (97% ee), as well as uracil and thymine derivatives, can be quickly prepared in a predictable manner (79 examples reported), which will be very useful in new drug discovery.

Water mediated synthesis of 6-amino-5-cyano-2-oxo-N-(pyridin-2-yl)-4-(p-tolyl)-2H-[1,2'-bipyridine]-3-carboxamide and 6-amino-5-cyano-4-(4-fluorophenyl)-2-oxo-N-(pyridin-2-yl)-2H-[1,2'-bipyridine]-3-carboxamide - An experimental and computational studies with non-linear optical (NLO) and molecular docking analyses

6-Amino-5-cyano-2-oxo-N-(pyridin-2-yl)-4-(p-tolyl)-2H-[1,2'-bipyridine]-3-carboxamide and 6-amino-5-cyano-4-(4-fluorophenyl)-2-oxo-N-(pyridin-2-yl)-2H-[1,2'-bipyridine]-3-carboxamide were synthesized through three-component reaction between N¹,N³-di(pyridin-2-yl)-malonamide, aldehyde and malononitrile in water using triethylamine as a base at room temperature. Synthesized compounds were characterized by using different techniques (FT-IR, NMR and X-ray diffraction). Additionally, the mentioned compounds were investigated by computational chemistry methods. Obtained results were supported with calculated results. Additionally, NLO properties and molecular docking analyses of related compounds were examined in detail. The binding modes of the compounds 4a and 4b were explored with the colchicine binding site of tubulin, from molecular docking studies, remarkable interactions have been observed for 4a and 4b near to the colchicines binding site of tubulin that may contribute to the inhibition of tubulin polymerization and anticancer activity.

Ethyl 4-chloro-2-oxo-1,2,5,6,7,8-hexahydroquinoline-3-carboxylate

In the title compound, C12H14ClNO3, the aliphatic ring of the hexahydroquinoline system adopts a half-chair conformation while the ethyl carboxylate substituent is inclined to the hexahydroquinoline ring system by 85.1 (2)°. In the crystal, a pair of N–H...O hydrogen bonds form an inversion dimer. The structure is further stabilized by C—H...O and C—H...Cl hydrogen bonds, forming a three-dimensional network.

Efficient and divergent synthesis of polyfunctionalized 2-pyridones from β-keto amides

Efficient and divergent one-pot synthesis of polyfunctionalized 2-pyridones from β-keto amides based on reaction condition selection was developed. The methodology offers several significant advantages including mild conditions, ease of handling, high yields, and a relatively broad range of substrates. Based on various experiments and observations, a plausible mechanism for the selective synthesis of 2-pyridones was proposed.

Divergent synthesis of 2-pyridones.

Chemoinformatics: a perspective from an academic setting in Latin America

This perspective discusses the current progress of a chemoinformatics group in a major university in Latin America. Three major aspects are discussed in a critical manner: research, education, and collaboration with industry and other public research networks. It is also presented an overview of the progress in applied research and development of research concepts. Efforts to teach chemoinformatics at the undergraduate and graduate levels are discussed. It is addressed how the partnership with industry and other not-for-profit research institutions not only brings additional sources of funding but, more importantly, increases the impact of the multidisciplinary work and offers the students to be exposed to other research environments. We also discuss the main perspectives and challenges that remain to be addressed in these settings.

Synthesis and antitumor activity against HepG-2, PC-3, and HCT-116 cells of some naphthyridine and pyranopyridinecarbonitrile derivatives

A series of substituted and fused heterocyclic derivatives 2-17 were synthesized using 3,5-bis(4-methoxybenzylidene)-1-propylpiperidin-4-one (1) as starting material. Treatment of 1 with malononitrile or semicarbazide afforded compounds 2 and 3, respectively. Condensation of 1 with ethyl cyanoacetate afforded naphthyridine-3-carbonitrile derivative 4, which reacted with phosphorus pentachloride and phosphoryl chloride to give chloro derivative 5. Treatment of 5 with thiosemicarbazide afforded compound 6. The reaction of 1 with malononitrile gave cyano aminopyrane derivative 7 which was condensed with pyromellitic dianhydride, phthalic anhydride, succinic anhydride, or morpholine in glacial acetic acid to obtain imide derivatives 8-11. Additionally, the reaction of 7 with aromatic aldehydes gave derivatives 12a-12c. Acetylation of 7 with acetic anhydride in boiling acetic acid gave N-acetyl derivative 13 which was cyclized to pyridine derivative 14 by refluxing in dioxane in the presence of triethylamine. Treatment of 7 with hydrazine hydrate gave pyrazolo derivative 15. Finally, the reaction of 7 with triethyl orthoformate in the presence of acetic anhydride gave formimidate 16 which was treated with hydrazine hydrate to form N-amino derivative 17. Some of the synthesized compounds were examined in vitro for their antitumor activity against HepG-2, PC-3, and HCT-116 human carcinoma cell lines using MTT assay.

Novel construction of diversely functionalized N-heteroaryl-2-pyridones via copper(ii)-catalyzed [3+2+1] annulation

A facile synthesis of diversely functionalized N-heteroaryl-2-pyridones is achieved by Cu(OTf)₂-catalyzed [3+2+1] annulation of various 2-aminopyridines via cascade reaction.

A highly efficient magnetic solid acid nanocatalyst for the synthesis of new bulky heterocyclic compounds

Fe₃O₄nanoparticles were coated with 3-aminopropyltriethoxysilane and further chemically modified with maleic anhydride to generate Fe₃O₄@APTES·MAH NPs. Then some new bulky heterocyclic compounds were synthesized using this catalyst.

Advances in the development of pyridinone derivatives as non-nucleoside reverse transcriptase inhibitors

Medicinal chemistry, computational design and biological screening have advanced pyridin-2(1H)-one derivatives as a promising class of non-nucleoside reverse transcriptase inhibitors for the treatment of HIV/AIDS.

Facile synthesis of the NNRTI microbicide MC-1220 and synthesis of its phosphoramidate prodrugs

A facile and novel synthetic route to MC-1220 was achieved by condensation of 4,6-dichloro-N,N-5-trimethylpyrimidin-2-amine (1) with the sodium salt of 2,6-difluorophenylacetonitrile, followed by methylation and strong acidic hydrolysis. The prodrugs of MC-1220 were synthesized by reaction of chlorophosphoramidate derivatives (7a-e) or α-acetobromoglucose with the sodium salt of MC-1220. The stability and anti-HIV-1 activity of phosphoramidate prodrugs turned out to be comparable to those of the parent drug MC-1220.

Critical Intermediates Reveal New Biosynthetic Events in the Enigmatic Colibactin Pathway

Colibactin is a potent genotoxin that induces DNA double-strand breaks; it is produced by Escherichia coli strains harboring a pks+ island. However, the structure of this compound remains elusive. Here, using transformation-associated recombination (TAR) cloning to perform heterologous expression, we took advantage of the significantly increased yield of colibactin pathway-related compounds to determine and isolate a series of vital (pre)colibactin intermediates. The chemical structures of compounds 8, 10 and 11 were identified by NMR and MS(n) analyses. The new 1H-pyrrolo[3,4-c]pyridine-3,6(2H,5H)-dione- and thiazole-containing compound 10 provides new insights regarding the biosynthetic pathway to (pre)colibactin and establishes foundations for future investigation of the intriguing (pre)colibactin structures and its modes of action.

Vilsmeier cyclization of α-acetyl-α-aroyl ketene-N,S-acetals: direct and efficient synthesis of halogenated pyridin-2(1H)-ones

An efficient synthetic route to 3-aroyl-5-formyl-4-halo pyridin-2(1H)-ones has been developed via Vilsmeier cyclization of 2-(ethylthio(arylamino)methylene)-1-alkylbutane-1,3-dione.

Synthesis and biological evaluation of 2-oxonicotinonitriles and 2-oxonicotinonitrile based nucleoside analogues

Drug resistance and emergence of new pathogens highlight the need for developing new therapeutic agents. We focused on 2-oxonicotinonitrile (2-ONN) as derivative of the natural product 2-pyridinone.1 Herein, we describe the synthesis of 2-ONNs bearing two aryl groups, which we coupled with organohalides, including three glycosyl bromides, to prepare the nucleoside analogues. Coupling occurred mostly at the 2-ONN ring nitrogen to give the aimed targets, and in a few cases, it happened at the 2-oxo position giving O-alkylation products. Free 2-ONNs and their acetylated nucleosides were tested against a number of viruses. The nucleoside analogue 2a_Ac showed good anti SARS-CoV and anti influenza A (H₅N₁) activities. Additionally, 7b had good activity against Gram positive bacterium, Bacillis subtilis.

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2-Oxonicotinonitriles with two aryl groups were coupled with several organohalides.

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The coupling occurred mostly at the ring nitrogen.

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In a few cases, the coupling occurred at the 2-oxo position.

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Antimicrobial and antiviral activities were tested for acetylated and free compounds.

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One nucleoside analogue showed good anti SARS and anti influenza activity.

4-Hy-droxy-6-methyl-pyridin-2(1H)-one

In the crystal structure of the title compound, C6H7NO2, N-H⋯O and O-H⋯O hydrogen bonds link the mol-ecules, forming a zigzag array along [001] and a layer structure parallel to the ab plane.

Methoxymethyl (MOM) group nitrogen protection of pyrimidines bearing C-6 acyclic side-chains

Novel N-methoxymethylated (MOM) pyrimidine (4−13) and pyrimidine-2,4-diones (15−17) nucleoside mimetics in which an isobutyl side-chain is attached at the C-6 position of the pyrimidine moiety were synthesized. Synthetic methods viaO-persilylated or N-anionic uracil derivatives have been evaluated for the synthesis of N-1- and/or N-3-MOM pyrimidine derivatives with C-6 acyclic side-chains. A synthetic approach using an activated N-anionic pyrimidine derivative afforded the desired N,N-1,3-diMOM and N-1-MOM pyrimidines 4 and 5 in good yield. Introduction of fluorine into the side-chain was performed with DAST as the fluorinating reagent to give a N,N-1,3-diMOM pyrimidine 13 with a 1-fluoro-3-hydroxyisobutyl moiety at C-6. Conformational study of the monotritylated N-1-MOM pyrimidine 12 by the use of the NOE experiments revealed the predominant conformation of the compound to be one where the hydroxymethyl group in the C-6 side-chain is close to the N-1-MOM moiety, while the OMTr is in proximity to the CH₃-5 group. Contrary to this no NOE enhancements between the N-1-MOM group and hydroxymethyl or fluoromethyl protons in 13 were observed, which suggested a nonrestricted rotation along the C-6 side-chain. Fluorinated N,N-1,3-diMOM pyrimidine 13 emerged as a model compound for development of tracer molecules for non-invasive imaging of gene expression using positron emission tomography (PET).

HIV-1 NNRTIs: structural diversity, pharmacophore similarity, and implications for drug design

Nonnucleoside reverse transcriptase inhibitors (NNRTIs) nowadays represent very potent and most promising anti-AIDS agents that specifically target the HIV-1 reverse transcriptase (RT). However, the effectiveness of NNRTI drugs can be hampered by rapid emergence of drug-resistant viruses and severe side effects upon long-term use. Therefore, there is an urgent need to develop novel, highly potent NNRTIs with broad spectrum antiviral activity and improved pharmacokinetic properties, and more efficient strategies that facilitate and shorten the drug discovery process would be extremely beneficial. Fortunately, the structural diversity of NNRTIs provided a wide space for novel lead discovery, and the pharmacophore similarity of NNRTIs gave valuable hints for lead discovery and optimization. More importantly, with the continued efforts in the development of computational tools and increased crystallographic information on RT/NNRTI complexes, structure-based approaches using a combination of traditional medicinal chemistry, structural biology, and computational chemistry are being used increasingly in the design of NNRTIs. First, this review covers two decades of research and development for various NNRTI families based on their chemical scaffolds, and then describes the structural similarity of NNRTIs. We have attempted to assemble a comprehensive overview of the general approaches in NNRTI lead discovery and optimization reported in the literature during the last decade. The successful applications of medicinal chemistry strategies, crystallography, and computational tools for designing novel NNRTIs are highlighted. Future directions for research are also outlined.

Consensus features of CP-MLR and GA in modeling HIV-1 RT inhibitory activity of 4-benzyl/benzoylpyridin-2-one analogues

The HIV-1 reverse transcriptase (RT) inhibitory activity of benzyl/benzoylpyridinones is modeled with molecular features identified in combinatorial protocol in multiple linear regression (CP-MLR) and genetic algorithm (GA). Among the features, nDB and LogP are found to be the most influential descriptors to modulate the activity. Although the coefficient of nDB suggested in favor of benzylpyridinones skeleton, the coefficient of LogP suggested the favorability of hydrophilic nature in compounds for better activity. The partial least squares analysis of the descriptors common to CP-MLR and GA has displayed their predictivity over the total descriptors identified in both the approaches. The back-propagation artificial neural networks model from the five most significant common descriptors (nDB, T(O..O), MATS8e, LogP, and BELp4) has explained 93.2% variance in the HIV-1 RT activity of the training set compounds and showed a test set r(2) of 0.89. The results suggest that the descriptors have the ability to identify the patterns in the compounds to predict potential analogues.