RESUMEN
A photocatalyst-free visible-light induced arylation of 2-aryl-2H-indazoles with aryl iodides has been developed for the first time to produce 3,2-diaryl-2H-indazoles in good to moderate yields. In this transformation, potassium tert-butoxide acts as an activator of the C-I bond and also as a scavenger of in situ generated HI in the reaction. This method exhibits high functional group tolerance with a wide substrate scope and it has been successfully applied to the synthesis of liver X receptor agonists and also for fluorescent probes. This is the first report on the photoarylation of 2-arylindazoles at the C3-position with aryl iodides under catalyst-free conditions.
RESUMEN
The present work represents a novel methodology for the selective arylation of coumarin-3-carboxylates with arylboronic acids via a photochemical route, marking the first-ever attempt for the direct alkenyl C-H arylation using rose bengal as a photocatalyst, which is a readily available and cost-effective alternative to transition metal catalysis. The reaction proceeds smoothly in MeOH/H2O solvent media in the presence of radical initiator affording the arylated products in good yields (60-80 %). The reaction parameters such as visible light, radical initiator, oxidant, anhydrous solvent, and inert atmosphere play a crucial role for the success of this methodology. The substituents present on the substrate show a significant effect on the conversion. This study provides a valuable contribution to the field of organic synthesis offering a new and efficient approach to the arylation of coumarin-3-carboxylic acid esters with a broad substrate scope and high functional group tolerance. It is a versatile method and provides a direct access to biologically relevant 4-arylcoumarin-3-carboxylates.
RESUMEN
Rhodium(III)-catalyzed [3 + 2]-spiroannulation of 2-aryl-1,4-benzoxazines with 4-hydroxy-2-alkynoates has been developed for the synthesis of highly rigid spirolactones in good yields with high regioselectivity. The reaction proceeds through a cascade of C-H activation followed by C-H annulation and lactonization. In this approach, two C-C and C-O bonds are formed in a single step. This is the first report on the spiroannulation of 2,3-dihydro-1,4-benzoxazines with 4-hydroxy-2-alkynoates.
RESUMEN
A novel three-component strategy has been developed for the synthesis of iminosugars in good to excellent yields. This is the first report on the Mannich type addition of cyclic 1,3-diketones to aza-acetal derived from hydroxy-γ-lactone and arylamine to produce a novel series of aza-sugars with high selectivity.
Asunto(s)
Aminas , Azúcares , Estereoisomerismo , Cetonas , IonesRESUMEN
An oxidative annulation of N-arylbenzimidamides with maleimides has been developed for the first time using a catalytic amount of the [Cp*RhCl2]2 complex for the synthesis of a diverse range of 1H-benzo[4,5]imidazo[2,1-a]pyrrolo[3,4-c]isoquinoline-1,3(2H)-dione derivatives. This method is versatile and atom-economical for producing polycyclic benzo[4,5]imidazo[2,1-a]pyrrolo[3,4-c] isoquinoline-1,3(2H)-dione scaffolds in a single step.
RESUMEN
A chiral Cu(i)-bisoxazoline complex catalyzed enantioselective electrophilic fluorination of 3-indolinone-2-carboxylates with NFSI has been accomplished to produce chiral 2-fluoro-3-indolinone-2-carboxylates in good yields with excellent enantioselectivities. This is the first report on the enantioselective fluorination of 2-substituted 3-indolinones using a chiral Cu(i)-bisoxazoline complex.
RESUMEN
The vital role played by microtubules in the cell division process, marks them as a potential druggable target to decimate cancer. A novel furan-2-carboxamide based small molecule, is a selective microtubule stabilizing agent (MSA) with IC50 ranging from 4 µM to 8 µM in different cancer cell lines. Inhibition of tubulin polymerization or stabilization of tubulin polymers abrogates chromosomal segregation during cell division, results in cell cycle arrest and leads to cell death due to the delayed repair mechanism. A novel furan-2-carboxamide based small molecule exhibited potent anti-proliferative and anti-metastatic property In-Vitro against the panel of cancer cells. Annexin V-FITC/PI, double staining reveals potent cytotoxic effect of SH09 against HeLa cells. FACS analysis displays induction of G2/M arrest and accumulation of subG1 population of cells upon treatment with SH09. Molecular docking study unveils SH09 binding affinity to the Taxol binding pocket of tubulin proteins and MM-GBSA also confirms strong binding energies of SH09 with tubulin proteins.
Asunto(s)
Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Furanos/farmacología , Microtúbulos/efectos de los fármacos , Antineoplásicos/síntesis química , Antineoplásicos/química , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Furanos/síntesis química , Furanos/química , Humanos , Mitosis/efectos de los fármacos , Estructura Molecular , Relación Estructura-Actividad , Células Tumorales CultivadasRESUMEN
Correction for 'A multi-component reaction for the synthesis of pyrido [1,2-b] isoquinoline derivatives via the [3 + 2] cycloaddition reaction between alkynes and in situ generated isoquinolinium ylides' by Sundar S. Shinde et al., Org. Biomol. Chem., 2019, 17, 4121-4128, DOI: 10.1039/C9OB00560A.
RESUMEN
BACKGROUND: Benzothiazine derivatives, because of their various biological activities have attracted particular attention in Med Chem and drug discovery efforts. The synthetic modifications of 1,2-benzothiazine 1,1-dioxides have been undertaken in order to explore and identify novel compounds or new analogues possessing promising biological activities. In our effort we have designed -oxicam derived bezothiazine-1,2,3-triazole derivatives as potential antibacterial agents. METHODS: These compounds were synthesized via a multi-step sequence involving the Cu catalyzed azide- alkyne cycloaddition (CuAAC) as a key step. The CuAAC proceeded at room temperature in DMF to afford 26 novel molecules in good (70-90%) yields. RESULTS: All these compounds were tested for their antibacterial properties against four strains of bacterial microorganisms and subsequently cytotoxic properties against lung and colon cancer cell lines. The compound 4e showed activities against majority of the bacterial species used (nearly comparable to amoxicillin, ciprofloxacin and ofloxacin against P. vulgaris) whereas 4d and 4f showed cytotoxicities selective towards cancer cells. CONCLUSION: The present bezothiazine-1,2,3-triazole framework represents a new template for the identification of novel and potent antibacterial/anticancer agents.
Asunto(s)
Benzotiadiazinas/química , Benzotiadiazinas/farmacología , Descubrimiento de Drogas/métodos , Triazoles/química , Triazoles/farmacología , Antibacterianos/síntesis química , Antibacterianos/química , Antibacterianos/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Antineoplásicos/farmacología , Benzotiadiazinas/síntesis química , Técnicas de Química Sintética , Humanos , Triazoles/síntesis químicaRESUMEN
Diphenyl ether derivatives inhibit mycobacterial cell wall synthesis by inhibiting an enzyme, enoyl-acyl carrier protein reductase (InhA), which catalyses the last step in the fatty acid synthesis cycle of genus Mycobacterium. To select and validate a protein crystal structure of enoyl-acyl carrier protein reductase of Mycobacterium tuberculosis for designing inhibitors using molecular modelling, a cross-docking and correlation study was performed. A series of novel 1-(3-(3-hydroxy-4-phenoxyphenyl)-5-phenyl-4,5-dihydro-1H-pyrazol-1-yl) ethan-1-ones were synthesized from this model and screened for their antitubercular activity against M. tuberculosis H37Rv. Compound PYN-8 showed good antitubercular activity on M. tuberculosis H37Rv (MIC = 4-7 µM) and Mycobacterium bovis (% inhibition at 10 µM = 95.91%). Cytotoxicity of all the synthesized derivatives was assessed using various cell lines, and they were found to be safe. Structure of PYN-8 was also confirmed by single-crystal X-ray diffraction. The molecular modelling studies also corroborated the biological activity of the compounds. Further, in silico findings revealed that all these tested compounds exhibited good ADME properties and drug likeness and thus may be considered as potential candidates for further drug development.
Asunto(s)
Antituberculosos/síntesis química , Antituberculosos/farmacología , Éteres Fenílicos/síntesis química , Éteres Fenílicos/farmacología , Tuberculosis/tratamiento farmacológico , Proteínas Bacterianas/metabolismo , Línea Celular , Línea Celular Tumoral , Simulación por Computador , Cristalografía por Rayos X , Diseño de Fármacos , Células HEK293 , Células HeLa , Humanos , Células MCF-7 , Pruebas de Sensibilidad Microbiana/métodos , Simulación del Acoplamiento Molecular , Mycobacterium tuberculosis/efectos de los fármacos , Células PC-3 , Relación Estructura-Actividad , Tuberculosis/metabolismoRESUMEN
An efficient Rh(III)-catalyzed bicyclization of 2-arylimidazo[1,2-a]pyridine with cyclic enones has been developed for the synthesis of bridged imidazopyridine derivatives in excellent yields up to 95%. The reaction proceeds through a sequential conjugate addition of ortho-C-H bond of aryl group followed by an intramolecular C3-alkylation of imidazopyridine ring in a highly regioselective manner.
RESUMEN
A highly enantio- and diastereoselective Mannich reaction of cyclic N-acyl ketimines generated in situ from 3-hydroxyisoindolin-1-ones with cyclic enones has been accomplished using a chiral phosphoric acid catalyst to afford the chiral isoindalinone derivatives in high yields with excellent enantioselectivities (upto 97 % ee). This is the first report on the synthesis of chiral isoindolin-1-ones bearing adjacent quaternary and tertiary stereogenic centers.
RESUMEN
Considering the importance of ultra-performance liquid chromatography-electrospray ionization-quadrupole time of flight-tandem mass spectrometry (UPLC-ESI-QTOF-MS/MS) hyphenated techniques for analysis of secondary metabolites from crude extracts, the present study was aimed at identification of secondary metabolites in acetone extract of the lichen Usnea longissima. From our study, 19 compounds were tentatively identified through comparison of exact molecular masses from their MS/MS spectra, mass fragmentation studies and comparison with literature data. In addition, potent cytotoxic activity of U. longissima extract prompted us to isolate four compounds, 18R-hydroxy-dihydroalloprotolichesterinic acid (19), neuropogolic acid (20), barbatic acid (21), and usnic acid (22) from this extract which were adequately identified through mass spectrometry and NMR spectroscopy. All four compounds displayed cytotoxic activity. Barbatic acid (21) manifested doxorubicin equivalent activity against A549 lung cancer cell line with IC50 of 1.78 µM and strong G0/G1 accumulation of cells. Poly ADP-ribose polymerase (PARP) cleavage confirmed that it induced cytotoxic activity via apoptosis. Finally, our work has discerned the depside, barbatic acid (21) from crude extract as a candidate anti-cancer molecule, which induces cell death by stepping up apoptosis.
Asunto(s)
Ascomicetos/efectos de los fármacos , Ascomicetos/metabolismo , Cromatografía Líquida de Alta Presión , Metabolómica , Ácidos Ftálicos/farmacología , Metabolismo Secundario , Espectrometría de Masa por Ionización de Electrospray , Acetona , Apoptosis/efectos de los fármacos , Ciclo Celular/efectos de los fármacos , Línea Celular , Cromatografía Líquida de Alta Presión/métodos , Relación Dosis-Respuesta a Droga , Humanos , Metabolómica/métodos , Conformación Molecular , Estructura Molecular , Ácidos Ftálicos/química , Espectrometría de Masa por Ionización de Electrospray/métodosRESUMEN
An efficient and one-pot tandem procedure for the synthesis of fused ethanopyrido [1,2-b] isoquinoline derivatives from ninhydrin, proline and alkynes has been developed. This strategy exhibits an unprecedented [3 + 2] cycloaddition reaction between alkynes and isoquinolinium ylide (1,3 dipole) generated in situ from proline and ninhydrin. This newly developed methodology features simple operation and is metal free. In this methodology overall three new C-C bonds, two C-N bonds, and three new rings are formed in a single step process.
RESUMEN
Correction for 'Magnetically recoverable Cu0/Fe3O4 catalyzed highly regioselective synthesis of 2,3,4-trisubstituted pyrroles from unactivated terminal alkynes and isocyanides' by Dipak Kumar Tiwari et al., Chem. Commun., 2016, 52, 4675-4678.
RESUMEN
An intramolecular annulation strategy has been developed for the synthesis of tetrahydrobenzo[e]pyrano[4,3-c][1,2]thiazine derivatives by means of coupling of aldehydes with 2-(4-hydroxybut-1-yn-1-yl)-N-arylsulfonamides using a catalytic amount of silver hexafluoroantimonate in toluene at 80 °C. This is the first report on the synthesis of fused benzo-δ-sultam derivatives through C-N, C-O, and C-C bond formations. The reaction proceeds through a cascade of hydroamination and Prins type cyclization.
RESUMEN
A novel efficient one-pot regioselective ring-expansion reaction of isatins with in situ generated α-aryl/heteroaryldiazomethanes for the construction of viridicatin alkaloids has been described under metal-free conditions. The utility of this protocol is further demonstrated in the synthesis of naturally occurring viridicatin, viridicatol, and substituted 3- O-methyl viridicatin and their scale up.
RESUMEN
An asymmetric aza-Friedel-Crafts alkylation reaction between indoles and indolenines that were derived inâ situ from 3-indolinone-2-carboxylates has been developed by using 3,3'-bis(triphenylsilyl)-1,1'-binaphthyl-2,2'-diyl hydrogen phosphate as a catalyst. The reaction proceeded under mild conditions and provided chiral indol-3-yl-3-indolinone-2-carboxylate derivatives in good yields with excellent ee values (up to 98.6 %). Similarly, the Mannich-type addition of indoline-3-ones to indolenines provided heterodimers with vicinal chiral quaternary centers. This method was successfully applied to the construction of the core structure of trigonoliimineâ C.
RESUMEN
[This corrects the article DOI: 10.1039/C6RA05661J.].
RESUMEN
A novel strategy has been developed for the synthesis of chromeno[3,4-b]pyrrol-4(3H)-one and substituted pyrrole derivatives through 1,5-electrocyclization of conjugated azomethine ylides. This is the first example of the preparation of highly substituted pyrrole derivatives from chromene-3-carboxaldehydes (non-enolizable aldehydes) and N-alkyl amino acids/esters. This method is simple and applicable to a diverse range of substrates.