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Rapid Assembly of Functionalized 2 H-Chromenes and 1,2-Dihydroquinolines via Microwave-Assisted Secondary Amine-Catalyzed Cascade Annulation of 2- O/ N-Propargylarylaldehydes with 2,6-Dialkylphenols. J Org Chem 2023; 88:11778-11792. [PMID: 37556760 DOI: 10.1021/acs.joc.3c01082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
An efficient, secondary amine-catalyzed cascade annulation of 2-O/N-propargylarylaldehydes with 2,6-dialkylphenols was established to access biologically relevant functionalized 2H-chromenes and 1,2-dihydroquinolines tethered with a synthetically useful p-quinone methide scaffold in high yields under microwave irradiation and conventional heating conditions. The microwave-assisted strategy was convenient, clean, rapid, and high yielding in which the reactions were completed in just 15 min, and the yields obtained were up to 95%. This highly atom-economical domino process constructed two new C-C double bonds and a six-membered O/N-heterocyclic ring in a single synthetic operation. Its mechanism process was rationalized as involving sequential iminium ion formation, nucleophilic addition, and intramolecular annulation steps. Furthermore, the synthesized 2H-chromene derivatives were transformed into valuable indeno[2,1-c]chromenes, 5H-indeno[2,1-c]quinolines, and oxireno[2,3-c]chromene via a palladium-catalyzed double C-H bond activation process and epoxidation, respectively.
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Diversity-Oriented Synthesis of Benzo[ f][1,4]oxazepine-, 2 H-Chromene-, and 1,2-Dihydroquinoline-Fused Polycyclic Nitrogen Heterocycles under Microwave-Assisted Conditions. J Org Chem 2023. [PMID: 37318181 DOI: 10.1021/acs.joc.3c00552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
An efficient, diversity-oriented synthesis of oxazepino[5,4-b]quinazolin-9-ones, 6H-chromeno[4,3-b]quinolines, and dibenzo[b,h][1,6]naphthyridines was established involving a substrate-based approach under microwave-assisted and conventional heating conditions in high yields (up to 88%). The CuBr2-catalyzed, chemoselective cascade annulation of O-propargylated 2-hydroxybenzaldehydes and 2-aminobenzamides delivered oxazepino[5,4-b]quinazolin-9-ones involving a 6-exo-trig cyclization-air oxidation-1,3-proton shift-7-exo-dig cyclization sequence. This one-pot process showed excellent atom economy (-H2O) and constructed two new heterocyclic rings (six- and seven-membered) and three new C-N bonds in a single synthetic operation. On the other side of diversification, the reaction between O/N-propargylated 2-hydroxy/aminobenzaldehydes and 2-aminobenzyl alcohols delivered 6H-chromeno[4,3-b]quinolines and dibenzo[b,h][1,6]naphthyridines involving sequential imine formation-[4 + 2] hetero-Diels-Alder reaction-aromatization steps. The influence of microwave assistance was superior to conventional heating, where the reactions were clean, rapid, and completed in 15 min, and the conventional heating required a longer reaction time at a relatively elevated temperature.
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A microwave-assisted intramolecular aminopalladation-triggered domino sequence: an atom economical route to 5,10-dihydroindeno[1,2- b]indoles. Org Biomol Chem 2023; 21:3121-3131. [PMID: 36960815 DOI: 10.1039/d3ob00041a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
A microwave-assisted, palladium(II)-catalyzed cascade reaction of 2-alkynylanilines tethered with an α,β-unsaturated carbonyl moiety was established to access 5,10-dihydroindeno[1,2-b]indoles in high yields (up to 84%) in a short reaction time. This operationally simple cascade process shows 100% atom economy and allows the construction of two new five-membered rings and two new (1 C-C and 1 C-N) bonds in a single synthetic attempt. The mechanistic pathway of this reaction is visualized involving intramolecular aminopalladation (5-endo-dig) followed by carbopalladation (olefin insertion) and protonolysis steps. A systematic comparison between microwave irradiation and conventional heating methods was also performed to demonstrate the supremacy of the microwave-assisted approach. This domino reaction requires no protecting groups for the amino group and the palladium catalyst needs no ligands. To the best of our knowledge, this is the first report on microwave-assisted nucleopalladation-initiated cascade transformation.
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Intramolecular oxypalladation-initiated domino sequence: One-pot, two-step regioselective synthesis of isoquinolines. Tetrahedron 2023. [DOI: 10.1016/j.tet.2023.133272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Palladium-Catalyzed Intramolecular Oxypalladation-Initiated Cascade: Solvent-Dependent Chemodivergent Approach to Functionalized Benzazepines and Tetrahydroquinolines. Chem Commun (Camb) 2023; 59:5233-5236. [PMID: 37040145 DOI: 10.1039/d3cc01370g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Palladium-catalyzed, solvent-dependent intramolecular oxypalladation-triggered domino sequences of internal alkynes bearing tethered nucleophilic carboxylic ester and electrophilic enone functionalities were developed for the chemodivergent synthesis of two completely distinct biologically significant...
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Microwave-assisted one-pot two-step imine formation-hetero-Diels-Alder-detosylation/aromatization sequence: direct access to dibenzo[ b, h][1,6]naphthyridines. Org Biomol Chem 2022; 20:7472-7482. [PMID: 36102029 DOI: 10.1039/d2ob01216b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A microwave-assisted, copper-catalyzed, one-pot, two-step reaction is established to access functionalized [1,6]naphthyridines in high yields (up to 96%) starting from 2-(N-propargylamino)benzaldehydes and arylamines. This rapid and operationally simple sequential reaction allowed the construction of two new heterocyclic rings and three new (2 C-C and 1 C-N) bonds in a single synthetic operation. This reaction tolerated various electron-donating and electron-withdrawing substituents well and delivered the desired products in a shorter reaction time under microwave irradiation. This reaction proceeds through a sequential imine formation, intramolecular [4 + 2] hetero-Diels-Alder reaction, and air oxidation, followed by detosylation-aromatization steps.
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Microwave-Assisted Copper(II)-Catalyzed Cascade Cyclization of 2-Propargylamino/Oxy-Arylaldehydes and O-Phenylenediamines: Access to Densely Functionalized Benzo[ f]Imidazo[1,2- d][1,4]Oxazepines and Benzo[ f]Imidazo[1,2- d][1,4]Diazepines. J Org Chem 2022; 87:8956-8969. [PMID: 35765119 DOI: 10.1021/acs.joc.2c00671] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A highly efficient microwave-assisted copper(II)-catalyzed cyclization cascade was established starting from readily accessible O/N-propargylated 2-hydroxy or 2-aminobenzaldehydes and o-phenylenediamines to synthesize densely functionalized imidazo[1,2-d][1,4]oxazepines and imidazo[1,2-d][1,4]diazepines in high yields (up to 93%). This one-pot two-step process was found to be highly atom economical (-H2O, -H2) and operationally simple and enabled the generation of two new heterocycle rings (seven- and five-membered) and three new C-N bonds in a single synthetic operation. These reactions well tolerated a variety of substituents including electron-donating and electron-withdrawing groups and furnished the desired fused heterocycles in high yields under microwave irradiation in a very short reaction time. The mechanism of the established protocol involves sequential imine formation-intramolecular cyclization-air oxidation followed by 7-exo-dig cyclization steps. A comparative study between the microwave-assisted approach and conventional heating was also performed to demonstrate the advantages of the microwave-assisted protocol in terms of high yield and shorter reaction time.
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Copper catalysis for the synthesis of quinolines and isoquinolines. COPPER IN N-HETEROCYCLIC CHEMISTRY 2021:249-288. [DOI: 10.1016/b978-0-12-821263-9.00007-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
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Direct Access to Bridged Tetrahydroquinolines and Chromanes via an InCl 3-Catalyzed Sequential Three-Component Cascade. J Org Chem 2020; 85:8062-8073. [PMID: 32452689 DOI: 10.1021/acs.joc.0c00893] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A sequential three-component cascade process was developed for the synthesis of bridged tetrahydroquinolines and chromanes bearing 2,6-methanobenzo[d][1,3]diazocine and 2,6-methanobenzo[g][1,3]oxazocine scaffolds, respectively, in good yields from readily available materials. The InCl3-catalyzed reaction progressed via enamine formation, Michael addition, intramolecular cyclization, and intramolecular iminium ion cyclization steps. Notably, this high atom economic approach (-2H2O) allowed the generation of four new bonds (1 C-C and 3 C-N or 1 C-C, 1 C-O and 2 C-N) and two heterocyclic rings in a single operation.
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Palladium(II)‐Catalyzed Direct Access to Indeno[1,2‐
c
]isochromen‐5(11
H
)‐Ones via Intramolecular Oxypalladation‐Initiated Cascade Process. Adv Synth Catal 2020. [DOI: 10.1002/adsc.202000456] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Chemodivergent synthesis of functionalized methanodibenzo[b,f][1,5]diazocin-13-ylmethanones and tetrahydroquinolines via solvent-dependent AB2 and A2B2 multicomponent annulation reactions. Org Chem Front 2020. [DOI: 10.1039/d0qo00449a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A solvent-dependent chemodivergent approach was developed for the synthesis of 6,12-methanodibenzo[b,f][1,5]diazocin-13-ylmethanones and 2,3,4-trisubstituted 1,2,3,4-tetrahydroquinolines involving two distinct AB2 and A2B2 multicomponent processes.
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Regioselective synthesis of tetrahydroquinolines via syn- and anti-nucleopalladation-initiated cascade processes. Org Biomol Chem 2020; 18:8474-8485. [DOI: 10.1039/d0ob01840f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Regioselective synthesis of tetrahydroquinolines via nucleopalladation-initiated cascade sequences was established.
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Oxidant-free, three-component synthesis of 7-amino-6 H-benzo[ c]chromen-6-ones under green conditions. RSC Adv 2019; 9:32946-32953. [PMID: 35529159 PMCID: PMC9073129 DOI: 10.1039/c9ra07108c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/03/2019] [Indexed: 01/24/2023] Open
Abstract
An oxidant-free three-component synthesis of biologically significant 7-amino-6H-benzo[c]chromen-6-ones was established involving a Sc(OTf)3 catalyzed three-component reaction between primary amines, β-ketoesters and 2-hydroxychalcones under green conditions. In this strategy, both the B and C rings of 6H-benzo[c]chromen-6-ones were constructed simultaneously starting from acyclic precursors by generating four new bonds including two C-C, one C-N and one C-O in a single synthetic operation. The mechanism of this sequential cascade process involves the initial formation of a β-enaminone intermediate followed by Michael addition with 2-hydroxychalcone, intramolecular cyclization, dehydration, lactonization and aromatization steps. Unlike the related literature approaches, this reaction delivered the products without the addition of any external oxidants to achieve the key aromatization step.
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Proline and its Derivatives as Organocatalysts for Multi‐ Component Reactions in Aqueous Media: Synergic Pathways to the Green Synthesis of Heterocycles. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900558] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Heterogeneous Amberlyst-15-catalyzed synthesis of complex hybrid heterocycles containing [1,6]-naphthyridine under metal-free green conditions. Org Biomol Chem 2019; 17:6872-6879. [PMID: 31268090 DOI: 10.1039/c9ob01256g] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
An efficient green protocol for the synthesis of complex hybrid heterocycles containing [1,6]-naphthyridine and coumarin/pyrazole moieties was established, involving an intramolecular [4 + 2] hetero Diels-Alder reaction as the key step. The biologically significant 12,13-dihydro-6H-benzo[h]chromeno[3,4-b][1,6]naphthyridin-6-ones and 6,10-dihydro-5H-benzo[h]pyrazolo[3,4-b][1,6]naphthyridines were synthesized starting from 2-(N-propargylamino)-arylaldehydes and 3-aminocoumarins or 3-methyl-1-aryl-1H-pyrazol-5-amines in the presence of an Amberlyst-15 catalyst in PEG-200 in good yields. The easy access to diverse complex molecules in a single operation from readily available starting materials, a commercially available, transition metal-free and recyclable catalyst, the use of a green solvent, a very high atom economy and the release of water as the only side product are the highlights of this protocol.
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Direct Access to 9-Chloro-1H-benzo[b]furo[3,4-e]azepin-1-ones via Palladium(II)-Catalyzed Intramolecular syn-Oxypalladation/Olefin Insertion/sp2-C–H Bond Activation Cascade. Org Lett 2019; 21:5784-5788. [DOI: 10.1021/acs.orglett.9b01482] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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17
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An improving data delivery method using EEDD algorithm for energy conservation in green cloud network. Soft comput 2019. [DOI: 10.1007/s00500-019-04027-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Palladium-Catalyzed Regioselective Syn-Chloropalladation-Olefin Insertion-Oxidative Chlorination Cascade: Synthesis of Dichlorinated Tetrahydroquinolines. Org Lett 2019; 21:3465-3469. [PMID: 31001984 DOI: 10.1021/acs.orglett.9b01295] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A palladium catalyzed cascade process involving syn-chloropalladation, intramolecular olefin insertion, and oxidative C-Cl bond formation reactions was demonstrated for the synthesis of dichlorinated tetrahydroquinolines in high yields (up to 93%). The N-propargyl arylamines having a tethered α,β-unsaturated carbonyl moiety underwent a regioselective syn-chloropalladation followed by a Heck-type reaction to deliver the tetrahydroquinoline scaffold. The rare insertion of the second chlorine atom was rationalized comprising a PdII/IV catalytic cycle and oxidative cleavage of the C-PdII bond.
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Diastereoselective ABB' Three-Component Synthesis of Highly Functionalized Spirooxindoles Bearing Five Consecutive Asymmetric Carbons. J Org Chem 2019; 84:4009-4016. [PMID: 30869516 DOI: 10.1021/acs.joc.8b03270] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The synthesis of spirooxindoles bearing tetrahydro-4 H-cyclopenta[ b]furan framework was established starting from isatin-derived aldehydes and 2 equiv of 1,3-dicarbonyl compounds involving a piperidine-catalyzed ABB' three-component domino process. This reaction was highly diastereoselective affording a single diastereomer of spirooxindoles with five consecutive asymmetric carbons including spiro and tetrasubstituted carbon centers. In addition, this waste-free (-2H2O) reaction showed high atom economy and step economy by creating four new bonds, including three C-C bonds and one C-O bond, and two rings (one carbo- and one heterocyclic) in a single operation. The mechanism of this three-component domino process involved sequential Knoevenagel condensation-Michael addition-intramolecular oxa-Michael addition-intramolecular aldol reactions.
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Energy efficient utilization of cloud resources using hybrid ant colony genetic algorithm for a sustainable green cloud environment. 2017 INTERNATIONAL CONFERENCE ON INTELLIGENT COMPUTING AND CONTROL (I2C2) 2017. [DOI: 10.1109/i2c2.2017.8321881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
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Energy-aware resource allocation for an unceasing green cloud environment. 2017 INTERNATIONAL CONFERENCE ON INTELLIGENT COMPUTING AND CONTROL (I2C2) 2017. [DOI: 10.1109/i2c2.2017.8321878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
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Synthesis of 6,12-Epiminodibenzo[b,f][1,5]diazocines via an Ytterbium Triflate-Catalyzed, AB 2 Three-Component Reaction. J Org Chem 2016; 81:9687-9694. [PMID: 27682636 DOI: 10.1021/acs.joc.6b01764] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
An efficient and selective procedure for the synthesis of epiminodibenzo[b,f][1,5]diazocines involving a AB2 three-component reaction is developed. Two equivalents of suitably substituted 2-aminoarylaldehydes reacted with arylamines in the presence of Yb(OTf)3 to afford the desired products in high yields. The reaction is highly atom-economic and waste-free, in addition to allowing the generation of two heterocyclic rings and four C-N bonds in a single operation. Significantly, this approach is complementary to the existing literature procedures, affording arylamine-derived products that could not be accessed previously. A plausible mechanism is proposed involving an imine formation-intermolecular annulation-intramolecular iminium ion cyclization sequence.
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The Nucleosome Remodeling and Deacetylase Complex NuRD Is Built from Preformed Catalytically Active Sub-modules. J Mol Biol 2016; 428:2931-42. [PMID: 27117189 PMCID: PMC4942838 DOI: 10.1016/j.jmb.2016.04.025] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 04/18/2016] [Indexed: 11/26/2022]
Abstract
The nucleosome remodeling deacetylase (NuRD) complex is a highly conserved regulator of chromatin structure and transcription. Structural studies have shed light on this and other chromatin modifying machines, but much less is known about how they assemble and whether stable and functional sub-modules exist that retain enzymatic activity. Purification of the endogenous Drosophila NuRD complex shows that it consists of a stable core of subunits, while others, in particular the chromatin remodeler CHD4, associate transiently. To dissect the assembly and activity of NuRD, we systematically produced all possible combinations of different components using the MultiBac system, and determined their activity and biophysical properties. We carried out single-molecule imaging of CHD4 in live mouse embryonic stem cells, in the presence and absence of one of core components (MBD3), to show how the core deacetylase and chromatin-remodeling sub-modules associate in vivo. Our experiments suggest a pathway for the assembly of NuRD via preformed and active sub-modules. These retain enzymatic activity and are present in both the nucleus and the cytosol, an outcome with important implications for understanding NuRD function. We have studied Drosophila nucleosome remodeling deacetylase (NuRD) assembly. NuRD consists of a core deacetylase complex, where MTA-like acts as the scaffold. This transiently associates with a chromatin remodeling sub-module including CHD4. Single-molecule imaging shows that the two sub-modules associate through MBD-like. NuRD comprises catalytically active sub-modules in both the cytosol and the nucleus.
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