- Palladium/benzoquinone-catalyzed electrochemical oxidation of alcohols under anaerobic conditions
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Primary and secondary alcohols are oxidized to aldehydes and ketones, respectively, under anaerobic conditions in DMF at 80°C, in the presence of a base and catalytic amounts of Pd(OAc)2 and p-benzoquinone. The latter oxidizes the transient Pd(0) formed in the catalytic cycle to Pd(II) and p-hydroquinone is re-oxidized electrochemically. Georg Thieme Verlag Stuttgart.
- Amatore, Christian,Cammoun, Chama,Jutand, Anny
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- Arylacetylenes as two-carbon synthons: Synthesis of eight-membered rings: Via CC bond cleavage
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The first synthesis of eight-membered N-containing heterocycles by oxidative bicyclization/ring extension of arylacetylenes and aryl amines has been achieved. This protocol uses arylacetylene as an unusual two-carbon synthon by incorporating the two parts of the cracked CC bond into the final product, which provides a new method for using arylacetylenes as two-carbon synthons and further enriches CC bond cleavage methodology. Moreover, this multi-component reaction can provide diverse fused elegant eight-membered N-heterocycles under mild conditions with wide substrate scopes.
- Zhao, Peng,Yu, Xiao-Xiao,Zhou, You,Huang, Chun,Wu, Yan-Dong,Zhu, Yan-Ping,Wu, An-Xin
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- Four-component reaction of α-naphthol, an arylglyoxal, aniline and a dialkyl acetylenedicarboxylate: A Michael addition of enamines to α,β-unsaturated γ-dicarbonyl compounds
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Seven new tetracyclic diesters [dialkyl 1-Anilino-4-Aryl-3-(1-hydroxynaphthalen-2-yl)-4-oxobut-1-ene-1,2-dicarboxylates] have been prepared in good yield by a one-pot four-component reaction between enamine intermediates (as Michael donors) generated from aniline and a dialkyl acetylenedicarboxylate and α,β-unsaturated β-dicarbonyl intermediates (as Michael acceptors) generated fromα-naphthol and an arylglyoxal without using a catalyst in ethanol at reflux conditions.
- Mehrabi, Hossein,Fadaei, Mohadeseh,Zadeh, Ashrafosadat Beheshti
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- Regioselective oxidative cross-coupling of benzo[d] imidazo[2,1- b] thiazoles with styrenes: A novel route to C3-dicarbonylation
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A novel I2 promoted, highly efficient metal-free and peroxide-free greener domino protocol for the C3-dicarbonylation of benzo[d]imidazo[2,1-b]thiazoles (IBTs) with styrenes has been developed via oxidative cleavage of the C(sp2)-H bond, followed by C3-nucleophilic attack of IBT and oxidation. Interestingly, under these conditions 2-(benzo[d]imidazo[2,1-b]thiazol-2-yl)aniline gave the benzo[4′,5′]thiazolo[2′,3′:2,3]imidazo[4,5-c]quinoline derivative via oxidative cleavage of the C(sp2)-H bond, followed by Pictet-Spengler cyclization and aromatization. This method offers the advantages of broad substrate scope, ecofriendly feature and high atom economy apart from higher yields.
- Shaik, Siddiq Pasha,Sultana, Faria,Ravikumar,Sunkari, Satish,Alarifi, Abdullah,Kamal, Ahmed
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- Synthesis of fused pyrroles containing 4-hydroxycoumarins by regioselective metal-free multicomponent reactions
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The reaction of arylglyoxals, 4-hydroxycoumarin, and aromatic amines such as 7-amino-2-methylchromone, 6/7-aminoflavone, 7-amino-4-methylcoumarin, 1-amino-9-fluorenone, 1-aminoanthraquinone and aniline derivatives in acetic acid medium under microwave conditions provides the corresponding regioselective fused pyrroles having hydroxycoumarin and aryl substituents. Alternatively, we have developed another method using in situ arylglyoxals from acetophenone derivatives by I2/DMSO promoted C-H oxidation followed by one-pot three component cyclization reactions to provide similar fused pyrroles. Using both the methods a series of novel pyrroles fused with pharmacologically important chromone, flavone, coumarin, fluorenone, and anthraquinone moieties were synthesized under metal-free reaction conditions in good to very good yields within a short reaction time. The structures of the synthesized fused pyrroles have been unambiguously confirmed by spectroscopic techniques, mass analysis and single crystal XRD.
- Mishra, Richa,Jana, Asim,Panday, Anoop Kumar,Choudhury, Lokman H.
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- Synthesis and solid-state luminescence of highly-substituted 6-amino-2H-pyran-2-one derivatives
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A fast and convenient synthesis and solid-state luminescence properties of new highly-substituted 6-amino-2H-pyran-2-one derivatives is described. These compounds were obtained from inexpensive and available 2-acyl(aroyl)-1,3-dicyano-1,3-bis-methoxycarbonylpropenides via regioselective heterocyclization under the action of sulfuric and hydroiodic acid. Compounds containing 6-amino-2H-pyran-2-one moiety are nearly unstudied, but are of interest for obtaining condensed biologically active compounds based on this scaffold.
- Karpov, Sergey,Kayukov, Yakov,Grigor'ev, Arthur,Nasakin, Oleg,Kayukova, Olga,Tafeenko, Viktor
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- A highly efficient protocol for the synthesis of new 3-(α-aroylamido)-4-hydroxycoumarin derivatives using SnCl2-SiO2 nanoparticles under solventfree conditions
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An efficient and simple protocol for the synthesis of the title compounds is described via a one-pot, three-component reaction of 4-hydroxycoumarin, aryl glyoxals and amides, using SnCl2-SiO2 nanoparticles as a heterogeneous catalyst
- Arfavi-Safari, Mona,Anaraki-Ardakani, Hossein,Badri, Rashid,Tahanpesar, Elham
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- Iodine-promoted five-component reaction using fragment assembly strategy to construct dihydrooxepines
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An iodine-promoted fragment assembly strategy for the synthesis of fused heterocycles has been established. It provides an efficient route to construct pyrazolone-oxepine-pyrazoles from phenylhydrazines, aryl methyl ketones and acetoacetate esters. Notably, acetoacetate esters play two distinct pivotal roles in the five-component reaction by realizing the unique reactivities of methyl, methylene and carbonyl groups to construct 3-methyl-5-pyrazolone skeletons and by the reaction of methyl and carbonyl groups to form a C (sp3)-O bond.
- Zhao, Peng,Wu, Xia,Geng, Xiao,Wang, Can,Wu, Yan-Dong,Wu, An-Xin
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- Enantioselective Photocatalytic [3 + 2] Cycloadditions of Aryl Cyclopropyl Ketones
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Control of stereochemistry in photocycloaddition reactions remains a substantial challenge; almost all successful catalytic examples to date have involved [2 + 2] photocycloadditions of enones. We report a method for the asymmetric [3 + 2] photocycloaddition of aryl cyclopropyl ketones that enables the enantiocontrolled construction of densely substituted cyclopentane structures not synthetically accessible using other catalytic methods. These results show that the dual-catalyst strategy developed in our laboratory broadens synthetic chemists' access to classes of photochemical cycloadditions that have not previously been feasible in enantioselective form.
- Amador, Adrian G.,Sherbrook, Evan M.,Yoon, Tehshik P.
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- A NEW FACILE SYNTHESIS OF α-DICARBONYL COMPOUNDS BY OXIDATION OF ALKYNES WITH Mo(VI) PEROXOCOMPLEX PROMOTED BY MERCURIC ACETATE
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Mercuric acetate promoted oxidation of diaryl-, dialkyl-, and aralkylalkynes with (HMPA)MoO(O2)2 in 1,2-dichloroethane affords the corresponding α-diketones in good yields.Likewise, terminal alkynes can be converted into α-ketoaldehydes in excellent yields by using the same oxidizing system.
- Ballistreri, Francesco P.,Failla, Salvatore,Tomaselli, Gaetano A.,Curci, Ruggero
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- Employing Arylacetylene as a Diene Precursor and Dienophile: Synthesis of Quinoline via the Povarov Reaction
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A novel I2-mediated Povarov reaction of arylacetylenes and anilines for the synthesis of 2,4-substituted quinolines has been developed, in which arylacetylene first acts as both a diene precursor and dienophile. This work further develops the Povarov reaction to expand the types of diene precursors. Preliminary mechanistic studies indicate that the I2/DMSO system realized the oxidative carbonylation of C(sp)-H of arylacetylene and then undergoes a [4 + 2] cycloaddition reaction.
- Yu, Xiao-Xiao,Zhao, Peng,Zhou, You,Huang, Chun,Wang, Li-Sheng,Wu, Yan-Dong,Wu, An-Xin
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- Iodine-Mediated Domino Protocol for the Synthesis of Benzamides from Ethylarenes via sp3 C-H Functionalization
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An efficient, metal-free domino protocol for the synthesis of benzamides has been developed from ethylarenes using aqueous ammonia. The reaction proceeds through the formation of triiodomethyl ketone intermediate in the presence of iodine as the promoter and TBHP as an oxidant followed by nucleophilic substitution with aqueous ammonia, forming an amide. This operationally simple, functional-group-tolerant tandem approach provides an easy access to the broad range of biologically important benzamides.
- Vadagaonkar, Kamlesh S.,Kalmode, Hanuman P.,Prakash, Sattey,Chaskar, Atul C.
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- Oxidative S-Dealkylation Reaction of Sulfide Catalyzed by Co(II)(bzacen)
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In the oxygenation reaction of alkyl sulfides with Co(II)(bzacen)-O2 system, oxidative S-C bond cleavage (S-dealkylation) was found to take place exclusively.The reactivity of S-dealkylation reaction was dependent markedly on both acidity of α-methylene and steric hindrance of alkyl sulfide.The peroxo-Co(III) species is presumed to be the intermediate in this S-dealkylation reaction.
- Watanabe, Yoshihito,Numata, Tatsuo,Oae, Shigeru
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- I2-Promoted Multicomponent Dicyclization and Ring-Opening Sequences: Direct Synthesis of Benzo[ e][1,4]diazepin-3-ones via Dual C-O Bond Cleavage
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A novel and efficient formal [4 + 2+1] annulation of aryl methyl ketones and 2-aminobenzyl alcohols for the synthesis of benzo[e][1,4]diazepin-3-ones is reported. This reaction successfully affords diverse seven-membered ring lactams via dual C-O bond cleavage. A preliminary mechanistic study showed that a multicomponent dicyclization and ring-opening sequence might occur, with the introduction of methyl sulfide proposed as the last step. This efficient strategy with mild reaction conditions and a broad substrate scope has potential applications in chemistry and medicine.
- Geng, Xiao,Wang, Can,Huang, Chun,Zhao, Peng,Zhou, You,Wu, Yan-Dong,Wu, An-Xin
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- Au-Pd alloy cooperates with covalent triazine frameworks for the catalytic oxidative cleavage of β-O-4 linkages
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To design highly efficient catalysts for the cleavage of the C-O/C-C bond is the key task in the depolymerization of lignin. Bimetallic alloy catalysts Au-Pd-CTFs were developed to be effective in the oxidative cleavage of β-O-4 lignin model compounds with O2. Au-Pd nanoparticles with an Au/Pd molar ratio between 1?:?1 and 1?:?1.5 showed the highest cleavage efficiency. The kinetics of the reaction process revealed that a synergistic effect between Au and Pd played a crucial role in the oxidation of Cα-OH into CαO, which was the rate-determining step for the whole oxidative cleavage process. Further insight revealed that the cooperative effect between Au-Pd nanoparticles and the support covalent triazine frameworks (CTFs) facilitated the cleavage of the formed β-O-4 ketone compound to the corresponding aromatics. In addition, Au-Pd-CTF catalysts also showed efficiency in the oxidative transformation of the organosolv lignin. This catalytic system will provide guidance in the oxidative cleavage of β-O-4 linkages in lignin.
- Zhao, Li,Shi, Song,Zhu, Guozhi,Liu, Meng,Gao, Jin,Xu, Jie
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- 1-(benzoylamino)-3-methylimidazolium chlorochromate (BAMICC), a new selective and mild reagent for the oxidation of allylic and benzylic alcohols
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A new mild chromium(VI) oxidizing reagent, the 1-(benzoylamino)-3-methylimidazolium chlorochromate (BAMICC) has been prepared as a stable yellow-orange solid which selectively oxidizes allylic and benzylic alcohols, including those bearing basic nitrogens, to carbonyl compounds.
- Martinez, Yolanda,De Las Heras, Maria A.,Vaquero, Juan J.,Garcia-Navio, Jose L.,Alvarez-Builla, Julio
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- A General Protocol for Radical Anion [3+2] Cycloaddition Enabled by Tandem Lewis Acid Photoredox Catalysis
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A method for intermolecular [3+2] cycloaddition between aryl cyclopropyl ketones and alkenes involving the combination of Lewis acid and photoredox catalysis is reported. In contrast to other more common methods for [3+2] cycloaddition, these conditions o
- Amador, Adrian G.,Sherbrook, Evan M.,Lu, Zhan,Yoon, Tehshik P.
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- Synergistic I2/Amine Promoted Povarov-Type Reaction for the Synthesis of 2-Acyl-3-aryl(alkyl)quinolines Using Aryl(alkyl)acetaldehydes as Alkene Surrogates
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A synergistic I2/amine promoted formal [4 + 2] cycloaddition of methyl ketones, arylamines, and aryl(alkyl)acetaldehydes as alkene surrogates has been established. This protocol allowed the modular synthesis of various 2-acyl-3-aryl(alkyl)quino
- Geng, Xiao,Wu, Xia,Zhao, Peng,Zhang, Jingjing,Wu, Yan-Dong,Wu, An-Xin
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- Efficient synthesis of terpyrrole derivatives by a pseudo-five-component reaction between pyrrole, β-enaminocarbonyls and arylglyoxals
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Pyrrole reacts with arylglyoxal monohydrates and enaminoketones or enaminoesters in alcoholic media in the presence of FeBr3 as a catalyst to produce 2,5-bis(1H-pyrrol-2-yl)-1H-pyrrole derivatives in high yields as the only product. Reactions a
- Masoudi, Mozhgan,Anary-Abbasinejad, Mohammad
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- Synthesis of 2-acyl-benzo[1,3-d]selenazoles via domino oxidative cyclization of methyl ketones with bis(2-aminophenyl) diselenide
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A general, practical and simple one-pot synthesis of 2-acyl-benzo[1,3-d]selenazoles was developed by reacting a wide range of 2-arylethane-1,2-diones, generated in situ from commercially available aryl methyl ketones, with bis(2-aminophenyl) diselenide, promoted by Na2S2O5 in DMSO at 100 °C. Comparatively, the reactions were conducted under conventional heating and microwave irradiation. The use of focused microwave irradiation drastically decreased the reaction time from 48 to 2 h with a gain in the reaction yield for most cases. Still, 2-phenylacyl-benzo[1,3-d]selenazole was elected to react with sodium borohydride and butylmagnesium bromide, giving the respective secondary and tertiary alcohols under mild reaction conditions.
- Balaguez, Renata A.,Betin, Eduardo S.,Barcellos, Thiago,Lenard?o, Eder J.,Alves, Diego,Schumacher, Ricardo F.
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- Phase-Transfer Catalytic Oxidation of Terminal Alkynes to Keto Aldehydes by Dilute Hydrogen Peroxide
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A phase-transfer procedure for the oxidation of terminal alkynes under mild conditions is described.The catalytic system involves dilute hydrogen peroxide, Na2MO4 salts (M=Mo(VI), W(VI)), and Hg(OAc)2.In the absence of mercuric derivative no oxidation takes place.By changing the pH of the aqueous phase and the nature of the phase transfer agent, either cationic or neutral, as well as the metal (Mo or W), carboxilic acids or α-keto aldehydes may be selectively obtained in fairly good yields.
- Ballistreri, Francesco Paolo,Failla, Salvatore,Tomaselli, Gaetano Andrea
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- NaHS·n H2O-induced umpolung: The synthesis of 2-acyl-3-aminoindoles from aryl methyl ketones and 2-aminobenzonitriles
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An efficient method for constructing 2-acyl-3-aminoindoles from methyl ketones and 2-aminobenzonitriles is described, in which NaHS·nH2O is used as a novel umpolung reagent for the first time in organic synthesis. Mechanistic studies revealed that the key step involved an Eschenmoser sulfide contraction reaction.
- Geng, Xiao,Wu, Xia,Wang, Can,Zhao, Peng,Zhou, You,Sun, Xuan,Wang, Ling-Jiao,Guan, Wen-Juan,Wu, Yan-Dong,Wu, An-Xin
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- Novel and convenient one-pot strategy for regioselective synthesis of new 5-aryl-3-methyl-1-phenyl-1,2-dihydro-7aH-pyrazolo[3,4-c]pyridazin-7a-ol derivatives
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Abstract: We describe a novel and simple regioselective synthesis of 5-aryl-3-methyl-1-phenyl-1,2-dihydro-7aH-pyrazolo[3,4-c]pyridazin-7a-ol derivatives via one-pot three-component reaction of arylglyoxalmonohydrates, 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, and hydrazine hydrate in presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) as base-organocatalyst at room temperature in acetonitrile. This one-pot method has the advantages of simple methodology, high atom economy, cost-effectiveness, high regioselectivity, and easy workup. Graphical Abstract: [Figure not available: see fulltext.].
- Rimaz, Mehdi,Mousavi, Hossein,Nikpey, Laya,Khalili, Behzad
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- Regioselective Synthesis of V-Shaped Bistriazinyl-phenanthrolines
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A new, regioselective synthesis of V-shaped 2,9-bis(6-(4-halophenyl)-1,2,4-triazin-3-yl)-1,10-phenanthrolines (4XPhBTPhen) ligands was developed, creating access to a simple and reliable synthesis of precursors for future supramolecular actinide complexing systems. Described is a reactant-directed regioselective synthetic method, which was found to be high yielding and reliable and yields exclusively 6,6′-phenyl BTPhen derivatives (including 4-chloro and 4-bromo) in five simple steps. Molecular and crystal structures of PhBTP and PhBTPhen products are fully determined and both were found to be in space group C2/c. Additionally, molecular and crystal structures of Z and E isomers of 2-hydrazono-2-phenylacetaldehyde oxime, a reagent in the synthetic route, reveal existence of strong intramolecular N-H?O hydrogen bonding in the Z isomer explaining its lower solubility in water.
- Coogan, Niall T.,Chimes, Michael A.,Raftery, James,Mocilac, Pavle,Denecke, Melissa A.
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- Iodine-Promoted N-H/α,β-C(sp3)-Trifunctionalization of l -Proline: Access to 3,4-Dihydrobenzo[ b][1,7]naphthyridines via Consecutive Decarboxylation/Ring Opening/Dicyclization
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A N-H/α,β-C(sp3)-trifunctionalization of l-proline, proceeding through an iodine-promoted consecutive decarboxylation/ring-opening/dicyclization process, is achieved. This strategy affords structurally diverse fused N-heterocycles in good yields with a wide substrate scope. Preliminary mechanistic studies indicate that catabolism of l-proline might be involved in this cascade reaction and the in situ generated intermediate 4-aminobutanal was identified as the key intermediate. Notably, this domino strategy enriches the reactivity of versatile l-proline in the synthesis of fused heterocycles.
- Geng, Xiao,Wang, Can,Zhao, Peng,Zhou, You,Wu, Yan-Dong,Wu, An-Xin
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- Experimental and Theoretical Studies on Iron-Promoted Oxidative Annulation of Arylglyoxal with Alkyne: Unusual Addition and Migration on the Aryl Ring
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An Fe(III)-promoted oxidative annulation reaction was developed for the synthesis of 1,2-naphthoquinones. A variety of substituted arylglyoxals and internal alkynes undergo the transformation in the presence of FeCl3 at room temperature to afford the 1,2-naphthoquinone products in good yields in a short reaction time. Interestingly, the products show unusual pseudomigration of the substituent on the arene ring of arylglyoxals. A possible mechanism involving Fe(III)-promoted formation of a vinyl cation from arylglyoxal and alkyne, electrophilic addition of the vinyl cation to the ipso carbon of the aryl group to give a spiral intermediate, and then migration of the keto carbon to the ortho carbon was proposed as key steps and verified using quantum mechanics.
- Hung, Chen-Hsun,Gandeepan, Parthasarathy,Cheng, Lin-Chieh,Chen, Liang-Yu,Cheng, Mu-Jeng,Cheng, Chien-Hong
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- Iodine-Promoted Oxidative Cross-Coupling of Unprotected Anilines with Methyl Ketones: A Site-Selective Direct C-H Bond Functionalization to C4-Dicarbonylation of Anilines
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An unprecedented direct dual C-H bond functionalization of unprotected anilines and methyl ketones has been demonstrated. It is the first example of iodine-promoted highly chemo- and site-selective oxidative C-H/C-H cross-coupling of anilines and methyl k
- Wu, Xia,Gao, Qinghe,Geng, Xiao,Zhang, Jingjing,Wu, Yan-Dong,Wu, An-Xin
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- Microwave-assisted green oxidation of alcohols with hydrogen peroxide catalyzed by iron complexes with nitrogen ligands
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Oxidation of primary and secondary alcohols, including two diols and glycerol, with H2O2 was catalyzed by the iron(II) complexes [FeL3](OTf)2 (L = 2,2′-bipyridine, 2,2′-bipyrimidine, 1,10-phenanthroline and substituted derivatives) and [FeL2](OTf)2 (L = bis(2-pyridinylmethyl)amine, 2,6-di(2-pyridyl)pyridine). The reactions were performed in acetonitrile, water or mixed solvent (typically water/acetonitrile 4:1) in a microwawe reactor at low power. Effect of addition of a cocatalyst, which in some cases improved the yields of the catalytic reaction, was investigated by means of NMR and UV–Visible techniques.
- Cozzi, Irene Sofia,Crotti, Corrado,Farnetti, Erica
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- A C-H Oxidation/Two-Fold Cyclization Approach to Imidazopyridoindole Scaffold under Mild Oxidizing Conditions
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An expeditious one-step synthesis of the imidazopyridoindole scaffold was achieved through the C-H oxidation/two-fold cyclization reaction of methyl ketone and tryptamine derivatives. Mild oxidizing conditions were employed to realize the efficient oxidation of C(sp3)-H bonds, while suppressing overoxidation of the intermediate and ensuring the cross-trapping of two in situ generated acylimine intermediates.
- Xiang, Jia-Chen,Wang, Zi-Xuan,Cheng, Yan,Ma, Jin-Tian,Wang, Miao,Tang, Bo-Cheng,Wu, Yan-Dong,Wu, An-Xin
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- Boric acid-catalyzed synthesis of fused 1,2,4-triazine derivatives: a new class of red fluorescent organic compounds
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[Figure not available: see fulltext.] Pyrido[1,2-b][1,2,4]triazines have been synthesized in good to excellent yields by condensation reaction between 1,6-diamino-2-oxo-4-phenyl-1,2-dihydropyridine-3,5-dicarbonitriles and arylglyoxals in the presence of b
- Darehkordi, Ali,Salehi, Vahid,Rahmani, Fariba,Karimipour, Masoud
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- Bioinspired iron(II)-β-diketonate and iron(II)-α-hydroxy ketone complexes of a carbanionic N3C ligand: Oxidation of metal center vs C[sbnd]C bond cleavage of co-ligand with dioxygen
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Two bioinspired low-spin iron(II)-β-diketonate complexes, [(L1)FeII(BA)] (2) and [(L1)FeII(DBM)] (3), and an iron(II)-α-hydroxy ketone complex [(L1)FeII(HAP)] (4) (L1 = tris(2-pyridylthio)methanido anion, BA = monoanionic benzoylacetone, DBM = monoanionic dibenzoylmethane and HAP = monoanionic 2-hydroxyacetophenone) of a tripodal carbanionic ligand were prepared from an iron(II) precursor complex [(L1)FeII(CH3CN)2](ClO4) (1). The dioxygen reactivity of the complexes (2, 3 and 4) was investigated to evaluate the effect of ligand geometry and of the spin state of iron on the C[sbnd]C bond cleavage of the co-ligands. Complexes 2 and 3 react with dioxygen to yield benzoic acid as a minor product. The major pathway involves the formation of the corresponding iron(III)-β-diketonate complexes, [(L1)FeIII(BA)](ClO4) (2ox-ClO4) and [(L1)FeIII(DBM)](ClO4) (3ox-ClO4). Complex 4, however, undergoes the C[sbnd]C bond cleavage of the iron-coodinated HAP to form benzoic acid as the major product. In the reaction, phenylglyoxal is formed as the minor product with concomitant generation of an iron-oxygen oxidant. The oxidant is able to transfer an oxygen atom to thioanisole and can exchange its oxygen atom with water. The reactivity patterns of the low-spin iron(II) complexes reported here are distinctly different from that of the corresponding high-spin complexes supported by a monoanionic facial N3 ligand. The results emphasize the role of spin-state of iron, the denticity of the supporting ligand, and the nature of co-ligand in affecting the C[sbnd]C bond cleavage reaction.
- Banerjee, Sridhar,Paine, Tapan Kanti
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- A direct phosphine-mediated synthesis of polyfunctionalized 1-aminopyrroles from arylglyoxals, phenylhydrazine and acetylene diesters
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A new and efficient one-pot synthesis of 1-Aminopyrrole derivatives by three-component reaction of dialkyl acetylenedicarboxylates, phenylhydrazine and arylglyoxals in the presence of triphenylphosphine is described. The reactions were performed in dichloromethane at room temperature and neutral conditions and afforded good yields of products.
- Poorand, Mahboobe Amirani,Anary-Abbasinejad, Mohammad,Darehkordi, Ali
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- Antifungal activities of ketoazomethines of phenyl glyoxal and p-substituted anilines
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A new series of ketoazomethines were synthesized by condensation of phenyl glyoxal (prepared by partial oxidation of acetophenone) with various p-substituted anilines viz. p-Cl, p-Br, p-NO2, p-(C2H 5)2N and p-CH
- Vats, Vishnu,Upadhyay,Sharma, Prathibha
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- Visible-Light-Driven Z -Selective Reaction of Methyl Ketones with DMSO: A Mild Synthetic Approach to Methylthio-Substituted 1,4-Enedione Promoted by Selectfluor
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Here we disclose a simple, visible-light-driven Z -selective synthesis of methylthio-substituted 1,4-enedione in a single step promoted by Selectfluor. Dimethyl sulfoxide is used as both the 'thio' source and the solvent. Molecular iodine and potassium persulfate are used as catalyst and oxidant, respectively. White light (CFL-30W) is used as the light source. The proposed mechanism involves a Kornblum reaction followed by aldol reaction.
- Rastogi, Gaurav K.,Deb, Mohit L.,Baruah, Pranjal K.
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- Synthesis of Pyrrole-2-carbaldehyde Derivatives by Oxidative Annulation and Direct Csp3-H to C - O Oxidation
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An efficient and practical de novo synthesis of pyrrole-2-carbaldehyde skeletons featuring oxidative annulation and Csp3-H to C - O oxidation is presented, exemplified by the preparation of pyrrole-2-carbaldehyde derivatives from aryl methyl ketones, arylamines, and acetoacetate esters. Preliminary mechanistic investigations indicate that the aldehyde oxygen atom originates from oxygen. Moreover, the developed scalable approach provides a distinct advantage over traditional oxidative functionalization of C-H moieties, avoiding the use of stoichiometric quantities of hazardous oxidants.
- Wu, Xia,Zhao, Peng,Geng, Xiao,Wang, Can,Wu, Yan-Dong,Wu, An-Xin
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- Iodine-catalyzed tandem oxidative coupling reaction: A one-pot strategy for the synthesis of new coumarin-fused pyrroles
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The simple and facile strategy for the synthesis of 2,3-disubstituted-chromeno[4,3-b]pyrrole-4(1H)-ones has been established. This method describes the Kornblum oxidation reaction of acetophenones, followed by the Knoevenagle treatment of the resulted (he
- Yahyavi, Hoda,Heravi, Majid M.,Mahdavi, Mohammad,Foroumadi, Alireza
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- Direct Oxidative Cleavage of Multiple Csp3-H Bonds and a C-C Bond in 2-(Pyridin-2-yl)acetate Derivatives: Formal [3 + 1 + 1] Synthesis of 3-(Pyridin-2-yl)indolizine Skeletons
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A novel iodine-promoted oxidative cross-coupling/cyclization of 2-(pyridin-2-yl)acetate derivatives and methyl ketones via the cleavage of multiple Csp3-H bonds has been developed, which also achieved efficient cleavage of a C-C bond in the 2-(pyridin-2-yl)acetate derivatives. This protocol represents an elegant molecular fragment assembly of diverse 3-(pyridin-2-yl)indolizines via a formal [3 + 1 + 1] annulation. Notably, the pyridine derivatives serve two pivotal roles to provide two fragments to construct 3-(pyridin-2-yl)indolizine skeletons, rather than the single role in building common indolizines.
- Wu, Xia,Zhao, Peng,Geng, Xiao,Zhang, Jingjing,Gong, Xingxing,Wu, Yan-Dong,Wu, An-Xin
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- Microwave-assisted selenium dioxide oxidation of aryl methyl ketones to aryl glyoxals
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We report an improved procedure for the synthesis of phenyl glyoxal and a series of para-substituted aryl glyoxals by microwave-assisted selenium dioxide oxidation. The reaction time has been reduced from several hours to three minutes for activated aryl methyl ketone substrates and 18 min for deactivated substrates, with all reactions affording quantitative conversion into the corresponding aryl glyoxals.
- Young, Ryan M.,Davies-Coleman, Michael T.
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- I2/PhI(OAc)2 Copromoted Amination Reaction: Synthesis of α-Dicarbonylsulfoximine Derivatives by Incorporating an Intact Dimethyl Sulfoxide
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An I2/PhI(OAc)2 copromoted strategy using dimethyl sulfoxide as an "S/C2/O" source for preparing α-dicarbonylsulfoximine derivatives is reported. This process involves oxidative coupling to construct a C-N bond and electrophilic amin
- Zhao, Peng,Wu, Xia,Geng, Xiao,Wang, Can,Zhou, You,Wu, Yan-Dong,Wu, An-Xin
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- Direct Synthesis of 2,3-Diaroyl Quinolines and Pyridazino[4,5- b]quinolines via an I2-Promoted One-Pot Multicomponent Reaction
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The first synthesis of 2,3-diaroyl quinolines via a formal [3 + 2 + 1] cycloaddition of enaminones, aryl methyl ketones, and aryl amines is disclosed. This reaction efficiently affords a 1,4-dicarbonyl scaffold, which is a useful building block for constructing complex fused heterocycles. Furthermore, the 1,4-dicarbonyl scaffold has been used directly to prepare pyridazino[4,5-b]quinoline skeletons in one-pot.
- Zhao, Peng,Wu, Xia,Zhou, You,Geng, Xiao,Wang, Can,Wu, Yan-Dong,Wu, An-Xin
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- Functionalized-1,3,4-oxadiazole ligands for the ruthenium-catalyzed Lemieux-Johnson type oxidation of olefins and alkynes in water
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Three arene-ruthenium(II) complexes bearing alkyloxy(5-phenyl-1,3,4-oxadiazol-2-ylamino)(4-trifluoromethylphenyl)methyl ligands were quantitatively obtained through the reaction of (E)-1-(4-trifluoromethylphenyl)-N-(5-phenyl-1,3,4-oxadiazol-2-yl)-methanimine with the ruthenium precursor [RuCl2(η6-p-cymene)]2 in a mixture of the corresponding alcohol and CH2Cl2 at 50 °C. The obtained complexes were fully characterized by elemental analysis, infrared, NMR and mass spectrometry. Solid-state structures confirmed the coordination of the 1,3,4-oxadiazole moiety to the ruthenium center via their electronically enriched nitrogen atom at position 3 in the aromatic ring. These complexes were evaluated as precatalysts in the Lemieux-Johnson type oxidative cleavage of olefins and alkynes in water at room temperature with NaIO4 as oxidizing agent. Good to full conversions of olefins into the corresponding aldehydes were measured, but low catalytic activity was observed in the case of alkynes. In order to get more insight into the mechanism, three analogue arene-ruthenium complexes were synthesized and tested in the oxidative cleavage of styrene. The latter tests clearly demonstrated the importance of the hemilabile alkyloxy groups, which may form more stable (N,O)-chelate intermediates and increase the efficiency of the cis-dioxo-ruthenium(VI) catalyst.
- Hkiri, Shaima,Touil, Soufiane,Samarat, Ali,Sémeril, David
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- An efficient synthesis of polyfunctionalized pyrroles by three-component reaction of arylglyoxals, Meldrum’s acid and ethyl 2-chloro-3-(arylamino)but-2-enoates
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A fast and convenient method for synthesis of some new functionalized pyrrole derivatives have been described via a three-component reaction between arylglyoxals, Meldrum’s acid and ethyl 2-chloro-3-(arylamino)but-2-enoate derivatives in excellent yields.
- Anary-Abbasinejad, Mohammad,Nezhad-shahrokhabadi, Fereshteh
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- Construction and regulation of imidazo[1,5-a]pyridines with AIE characteristics via iodine mediated Csp2?H or Csp?H amination
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The widespread applications of aggregation-induced emission luminogens (AIEgens) inspire the creation of AIEgens with novel structures and functionalities. In this work, we focused on the direct and efficient synthesis of a new type of AIEgens, imidazo[1,5-a]pyridicne derivatives, via iodine mediated cascade oxidative Csp2–H or Csp–H amination route from phenylacetylene or styrenes under mild conditions. The resulted compounds showed excellent AIE characteristics with tunable maximum emissions, attractive bioimaging performance, and potential anti-inflammatory activity, which exert broad application prospects in material, biology, medicine, and other relevant areas.
- Zhang, Jun,She, Mengyao,Liu, Lang,Liu, Mengdi,Wang, Zhaohui,Liu, Hua,Sun, Wei,Liu, Xiaogang,Liu, Ping,Zhang, Shengyong,Li, Jianli
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p. 3083 - 3086
(2021/06/28)
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- Iodine-Promoted Formal [3+2] Cycloaddition of Enaminone: Access to 2-Hydroxy-1,2-dihydro-pyrrol-3-ones with Quaternary Carbon Center
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A novel iodine promoted cyclization of enaminone with aryl methyl ketones has been developed as a straightforward method for constructing 2-hydroxy-pyrrol-3(2H)-ones. This strategy affords structurally diverse 2-hydroxy-pyrrol-3(2H)-ones rings in high yields. Moreover, a quarternary alcohol has been constructed efficiently in the reaction. Product purification required only washing with CH2Cl2 solvent, thereby avoiding traditional chromatography and recrystallization, making this an example of group-assisted purification chemistry.
- Yu, Xiao-Xiao,Zhao, Peng,Zhou, You,Huang, Chun,Wang, Li-Sheng,Wu, Yan-Dong,Wu, An-Xin
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p. 12141 - 12147
(2021/09/07)
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- Electrochemical oxidative synthesis of 2-benzoylquinazolin-4(3: H)-one via C(sp3)-H amination under metal-free conditions
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An electrochemically induced C(sp3)-H amination of 2-aminobenzamides with ketones using TBAI as a catalyst was developed, and provided 2-benzoylquinazolin-4(3H)-ones under metal-free conditions. The reaction proceeded using the relatively low-toxicity methanol as the solvent, employed molecular oxygen as the ideal green oxidant in a simple undivided cell, and exhibited high atom economy. The mechanism of this C(sp3)-H amination strategy was concluded to involve generation of an acetophenone radical, and its easy further oxidation to form 2-oxo-2-phenylacetaldehyde.
- Hu, Yongzhi,Ma, Xinhua,Hou, Huiqing,Sun, Weiming,Tu, Shuqing,Wu, Mei,Lin, Rongkun,Xu, Xiuzhi,Ke, Fang
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p. 6374 - 6379
(2021/10/12)
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- Diversity-oriented synthesis of imidazo[1,2-a][1,3,5]triazine derivatives from 2-amine-[1,3,5]triazines with ketones
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An I2-mediated annulation of 2-amino[1,3,5]triazines and ketones for the synthesis of imidazo[1,2-a][1,3,5]triazines is presented. Electron rich, or electron poor acetophenone and heterocycle ketones, as well as propiophenone, are functionalize
- Zhao, Wanqiu,Zhang, Cheng,Zhong, Pengzhen,Zhou, Wei,Zhang, Chen,Cui, Dong-Mei
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p. 10715 - 10718
(2021/10/20)
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- Mechanochemical Synthesis of 1,2-Diketoindolizine Derivatives from Indolizines and Epoxides Using Piezoelectric Materials
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A simple and efficient mechanochemical-induced approach for the synthesis of 1,2-diketoindolizine derivatives has been developed. BaTiO3 was used as the piezoelectric material in this transformation. This method features no usage of solvent, simple experimental operation, scalable potential, and high conversion efficiency, which make it attractive and practical.
- Wang, Yumei,Zhang, Ziwu,Deng, Lichan,Lao, Tianfeng,Su, Zhengquan,Yu, Yue,Cao, Hua
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supporting information
p. 7171 - 7176
(2021/09/14)
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- Nature of the Nucleophilic Oxygenation Reagent Is Key to Acid-Free Gold-Catalyzed Conversion of Terminal and Internal Alkynes to 1,2-Dicarbonyls
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2,3-Dichloropyridine N-oxide, a novel oxygen transfer reagent, allows the conductance of the gold(I)-catalyzed oxidation of alkynes to 1,2-dicarbonyls in the absence of any acid additives and under mild conditions to furnish the target species, including those derivatized by highly acid-sensitive groups. The developed strategy is effective for a wide range of alkyne substrates such as terminal- and internal alkynes, ynamides, alkynyl ethers/thioethers, and even unsubstituted acetylene (40 examples; yields up to 99%). The oxidation was successfully integrated into the trapping of reactive dicarbonyls by one-pot heterocyclization and into the synthesis of six-membered azaheterocycles. This synthetic acid-free route was also successfully applied for the total synthesis of a natural 1,2-diketone.
- Dubovtsev, Alexey Yu.,Shcherbakov, Nikolay V.,Dar'in, Dmitry V.,Kukushkin, Vadim Yu.
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p. 745 - 757
(2020/02/04)
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- Au(I)-Catalyzed Hydration of 1-Iodoalkynes Leading to α-Iodoketones
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A catalytic protocol for the Au(I)-catalyzed hydration of 1-iodoalkynes is disclosed. The use of Au(I)–NHC catalyst enabled the straightforward synthesis of a variety of α-iodomethyl ketones in good to excellent yields. The utility of this simple method is further highlighted by showcasing iodination/hydration and hydration/oxidation sequential protocols leading to the construction of molecular complexity.
- Cazin, Catherine S. J.,Gómez-Herrera, Alberto,Hashim, Ishfaq Ibni,Nahra, Fady,Porré, Marre
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p. 6790 - 6794
(2020/11/23)
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- Visible-Light-Induced Regioselective Dicarbonylation of Indolizines with Oxoaldehydes via Direct C-H Functionalization
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A metal-free system for regioselective dehydrogenative cross-couplings between indolizines and oxoaldehydes catalyzed by visible light under mild conditions has been described. As an atom economical and eco-friendly protocol, the reaction proceeds in good yields using inexpensive, readily available visible-light sources and the environmentally friendly oxidant oxygen. Various valuable 1,2-dicarbonyl derivatives attached to an indolizine core were easily accessed by the direct dicarbonylation of the sp2 C-H bond.
- Teng, Lili,Liu, Xiang,Guo, Pengfeng,Yu, Yue,Cao, Hua
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supporting information
p. 3841 - 3845
(2020/05/08)
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- New synthesis of 2-aroylbenzothiazolesviametal-free domino transformations of anilines, acetophenones, and elemental sulfur
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A new synthesis of 2-aroylbenzothiazolesviaiodine-promoted domino transformations of anilines, acetophenones, and elemental sulfur was demonstrated. The highlights of this tandem synthesis are (1) easily available anilines and acetophenones as feedstock;
- Doan, Khang V.,Doan, Son H.,Huynh, Tien V.,Luong, Ngoc T. K.,Nguyen, Duyen T. P.,Nguyen, Tung T.,Phan, Nam T. S.
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p. 18423 - 18433
(2020/06/08)
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- Iodine-Promoted Multicomponent Synthesis of 2,4-Diamino-1,3,5-triazines
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A novel and efficient multicomponent cyclization of methyl ketones, cyanamides, and arylamines for the synthesizing 2,4-diamino-1,3,5-triazines via consecutive formation of four C-N bonds is reported. This multicomponent reaction is characterized by the employment of two molecules of cyanamide for double C(sp3)-H amination of methyl ketones, avoiding complicated prepreparation of substrates and expanding the substrate scope. Furthermore, this multicomponent cyclization strategy provides a new approach for generating diverse 2,4-diamino-1,3,5-triazines with a broad substrate scope under mild conditions.
- Zhao, Peng,Zhou, You,Yu, Xiao-Xiao,Huang, Chun,Wu, Yan-Dong,Yin, Guodong,Wu, An-Xin
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supporting information
p. 8528 - 8532
(2020/11/03)
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- Iodine-mediated C-N and N-N bond formation: A facile one-pot synthetic approach to 1,2,3-triazoles under metal-free and azide-free conditions
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A novel strategy towards the synthesis of 1,4-disubstituted 1,2,3-triazoles via C-N and N-N bond formation has been demonstrated under transition metal-free and azide-free conditions. These 1,2,3-triazoles were obtained in a regioselective manner from commercially available anilines, aryl alkenes/aryl alkynes and N-tosylhydrazines using I2 under O2 atmosphere. Broad substrate scope, milder reaction conditions, good to moderate yields and clean protocol are the notable features of the method. Moreover, this protocol is amenable for the generation of a library of medicinally important key building blocks.
- Mani, Geeta Sai,Donthiboina, Kavitha,Shaik, Siddiq Pasha,Shankaraiah, Nagula,Kamal, Ahmed
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p. 27021 - 27031
(2019/09/13)
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- A simple route for synthesis of 5-(furan-3-yl)barbiturate/thiobarbiturate derivatives via a multi-component reaction between arylglyoxals, acetylacetone and barbituric/thiobarbituric acid
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An effective protocol for the synthesis of 5-(furan-3-yl)barbiturate and 5-(furan-3-yl)thiobarbiturate derivatives through a one-pot three-component reaction of readily available starting materials arylglyoxals, barbituric acid or thiobarbituric acid and acetylacetone in water as solvent is reported.
- Dehghanzadeh, Fatemeh,Shahrokhabadi, Fereshteh,Anary-Abbasinejad, Mohammad
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p. 133 - 141
(2019/04/17)
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- Mono- or di-substituted imidazole derivatives for inhibition of acetylcholine and butyrylcholine esterases
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Mono- or di-substituted imidazole derivatives were synthesized using a one-pot, two-step strategy. All imidazole derivatives were tested for AChE and BChE inhibition and showed nanomolar activity similar to that of the test compound donepezil and higher than that of tacrine. Structure activity relationship studies, docking studies to on X-ray crystal structure of AChE with PDB code 1B41, and adsorption, distribution, metabolism, and excretion (ADME) predictions were performed. The synthesized core skeleton was bound to important regions of the active site of AChE such as the peripheral anionic site (PAS), oxyanion hole (OH), and anionic subsite (AS). Selectivity of the reported test compounds was calculated and enzyme kinetic studies revealed that they behave as competitive inhibitors, while two of the test compounds showed noncompetitive inhibitory behavior. ADME predictions revealed that the synthesized molecules might pass through the blood brain barrier and intestinal epithelial barrier and circulate freely in the blood stream without binding to human serum albumin. While the toxicity of one compound on the WS1 (skin fibroblast) cell line was 1790 μM, its toxicity on the SH-SY5Y (neuroblastoma) cell line was 950 μM.
- Kuzu, Burak,Tan, Meltem,Taslimi, Parham,Gül?in, ?lhami,Ta?p?nar, Mehmet,Menges, Nurettin
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p. 187 - 196
(2019/02/06)
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- Exocyclic N-Acyliminium Ion (NAI) Cyclization: Access to Fully Substituted Oxazoles and Furocoumarins
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A concise, one-pot route to oxazoles and furocoumarins has been reported. The key step in this transformation involves in situ generation of N-acyliminium ion (NAI) precursor under catalyst and solvent-free conditions and their further transformations promoted by superacid in the same pot. We have also presented the experimental evidence for the involvement of proto-solvated novel exocyclic N-acyliminium ion. Further, the UV-visible and fluorescence studies revealed that few of the compounds reported here exhibited emission of blue light upon irradiation in EtOH in the region of 404-422 nm.
- Babu, Venkata Nagarjuna,Murugan, Arumugavel,Katta, Narenderreddy,Devatha, Suman,Sharada, Duddu S.
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p. 6631 - 6641
(2019/06/07)
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- Modular Synthesis of Di- A nd Trisubstituted Imidazoles from Ketones and Aldehydes: A Route to Kinase Inhibitors
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A one-pot and modular approach to the synthesis of 2,4(5)-disubstituted imidazoles was developed based on ketone oxidation, employing catalytic HBr and DMSO, followed by imidazole condensation with aldehydes. This methodology afforded twenty-nine disubstituted NH-imidazoles (23%-85% yield). A three-step synthesis of 20 kinase inhibitors was achieved by employing this oxidation-condensation protocol, followed by bromination and Suzuki coupling in the imidazole ring to yield trisubstituted NH-imidazoles (23%-69%, three steps). This approach was also employed in the synthesis of known inhibitor GSK3037619A.
- De Toledo, Ian,Grigolo, Thiago A.,Bennett, James M.,Elkins, Jonathan M.,Pilli, Ronaldo A.
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supporting information
p. 14187 - 14201
(2019/10/16)
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- Pyrazine dicarboxylate-bridged arsenotungstate: Synthesis, characterization, and catalytic activities in epoxidation of olefins and oxidation of alcohols
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A praseodymium(iii)-containing arsenotungstate K16H15Li7[Pr2(H2O)3(pzdc)As3W29O103]2·38H2O (1) (pzdc = pyrazine-2,3-dicarboxylic acid) was synthesized by a conventional aqueous solution method and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), and single crystal X-ray diffraction. Structural analysis revealed that compound 1 was constructed by two identical subunits {Pr2(H2O)3(AsW9O33)3W2O4} bridged together by two pzdc ligands. In addition, compound 1 could act as an efficient catalyst for the epoxidation of olefins and oxidation of alcohols with hydrogen peroxide (H2O2) as the oxidant. In particular, the turnover frequency (TOF) in the oxidation of 1-phenylethanol reached up to 10170 h-1, which is higher than that of previously reported catalysts.
- Ma, Xinyi,He, Peipei,Xu, Baijie,Lu, Jingkun,Wan, Rong,Wu, Hechen,Wang, Yuan,Ma, Pengtao,Niu, Jingyang,Wang, Jingping
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supporting information
p. 12956 - 12963
(2019/09/07)
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- Synthesis of 2-oxo-acetamidines via copper-catalyzed oxidative cross-coupling of Α-amino ketone compounds with amines
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A general and efficient method for the synthesis of 2-oxo-acetamidines via copper-catalyzed oxidative cross-coupling of amines with α-amino ketone compounds was achieved. In this reaction, the C ? N bond of α-amino ketone is broken and new C ? N and C[dbnd]N bonds are constructed in one single transformation. This reaction system has a broad substrate scope and provides a facile pathway for the synthesis of 2-oxo-acetamidines.
- Wang, Pengjie,Xiong, Yi,Qin, Yiqun,Zhang, Jiajia,Yi, Niannian,Xiang, Jiannan,Deng, Wei
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- Controllable chemoselectivity in the coupling of bromoalkynes with alcohols under visible-light irradiation without additives: Synthesis of propargyl alcohols and α-ketoesters
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The chemoselectivity of visible-light-induced coupling reactions of bromoalkynes with alcohols can be controlled by simple changes to the reaction atmosphere (N2 or O2). A N2 atmosphere favours propargyl alcohols via a direct C-C coupling process, whereas an O2 atmosphere results in the generation of α-ketoesters through the oxidative CC/C-O coupling pathway.
- Ni, Ke,Meng, Ling-Guo,Ruan, Hongjie,Wang, Lei
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p. 8438 - 8441
(2019/07/22)
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- Iodine-DMSO-promoted divergent reactivities of arylacetylenes
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An unprecedented set of efficient, economical, atom-economic and exceedingly selective I2-DMSO-promoted methods is described for the generation of different structures. The reaction represents the first of its kind, involving the use of different iodine concentrations, temperatures, acids and salt to adjust the selectivity for the synthesis of different alkenes, α-functionalized ketones and α-ketomethylthioesters.
- Rather, Suhail A.,Kumar, Atul,Ahmed, Qazi Naveed
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p. 4511 - 4514
(2019/04/26)
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- Synthesis of 2,5-Disubstituted Oxazoles from Arylacetylenes and α-Amino Acids through an i 2 /Cu(NO 3) 2 ?3H 2 O-Assisted Domino Sequence
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A new strategy has been developed for the synthesis of 2,5-disubstituted oxazoles from easily available arylacetylenes and α-amino acids in the presence of Cu(NO 3) 2 ?3H 2 O and iodine. This reaction process involves the I 2 /Cu(NO 3) 2 ?3H 2 O-assisted transformation of arylacetylene to α-iodo acetophenone, Kornblum oxidation to phenylglyoxal, condensation to imine, decarboxylation/annulation/oxidation reaction sequence to approach 2,5-disubstituted oxazoles.
- Wang, Jungang,Cheng, Yan,Xiang, Jiachen,Wu, Anxin
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supporting information
p. 743 - 747
(2019/03/26)
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- KI-Promoted Oxidative Coupling of Styrenes with Indoles under Metal-Free Conditions: Facile Access to C-3 Dicarbonyl Indoles
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A new and efficient method for the synthesis of C-3 dicarbonyl indoles via oxidative cross-coupling of styrenes with indoles under metal-free conditions has been developed. Moreover, a broad scope of C-3 dicarbonyl indoles in moderate to good yields were obtained, and a plausible mechanism is proposed based on control and isotope-labeling experiments.
- Fang, Zheng,Guo, Kai,Guo, Shiyu,He, Wei,Li, Xin,Liu, Chengkou,Yang, Zhao,Zhou, Bochao,Zhu, Ning
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p. 3511 - 3519
(2019/09/07)
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- Copper catalyzed photoredox synthesis of α-keto esters, quinoxaline, and naphthoquinone: Controlled oxidation of terminal alkynes to glyoxals
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Herein, we report a facile visible light induced copper catalyzed controlled oxidation of terminal CC alkynes to α-keto esters and quinoxalines via formation of phenylglyoxals as stable intermediates, under mild conditions by using molecular O2 as a sustainable oxidant. The current copper catalysed photoredox method is simple, highly functional group compatible with a broad range of electron rich and electron poor aromatic alkynes as well as aliphatic alcohols (1°, 2° and 3° alcohols), providing an efficient route for the preparation of α-keto esters (43 examples), quinoxaline and naphthoquinone with higher yields than those in the literature reported thermal processes. Furthermore, the synthetic utility of the products has been demonstrated in the synthesis of two biologically active molecules, an E. coli DHPS inhibitor and CFTR activator, using the current photoredox process. In addition, we applied this methodology to the one-pot synthesis of a heterocyclic compound (quinoxaline, an FLT3 inhibitor) by trapping the intermediate phenylglyoxal with O-phenylenediamine. The intermediate phenylglyoxal can also be isolated and further reacted with an internal alkyne to form naphthoquinone. This process can be readily scaled up to the gram scale.
- Das, Deb Kumar,Kumar Pampana, V. Kishore,Hwang, Kuo Chu
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p. 7318 - 7326
(2018/10/15)
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- Oxidative C-C Bond Cleavage for the Synthesis of Aryl Carboxylic Acids from Aryl Alkyl Ketones
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A metal-free and one-pot two-step synthesis of aryl carboxylic acids from aryl alkyl ketones has been achieved. The reactions were performed with iodine as the catalyst, DMSO and TBHP as the oxidants. Under the optimal reaction conditions, a number of aryl alkyl ketones could be converted into their corresponding aryl carboxylic acids in good to excellent yields (up to 94%).
- Xu, Liang,Wang, Shengpeng,Chen, Bajin,Li, Meichao,Hu, Xinquan,Hu, Baoxiang,Jin, Liqun,Sun, Nan,Shen, Zhenlu
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supporting information
p. 1505 - 1509
(2018/05/25)
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- A convergent synthesis of vinyloxyimidazopyridine: Via Cu(i)-catalyzed three-component coupling
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The synthesis of vinyloxyimidazopyridine with complete regio- and stereoselectivity has been achieved by the Cu(i)-catalyzed three-component coupling of 2-aminopyridine, 2-oxoaldehyde and alkyne. This protocol is operationally very simple and has much potential for the synthesis of heteroarylated vinyl ethers from basic chemicals. Steroidal imidazopyridinyl vinyl ether was obtained successfully from ethynylestradiol.
- Samanta, Sadhanendu,Mondal, Susmita,Hajra, Alakananda
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supporting information
p. 1088 - 1092
(2018/02/21)
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- Molecular iodine-catalysed oxidative CO-C(alkyl) bond cleavage of aryl/heteroaryl alkyl ketones: an efficient strategy to access fused polyheterocycles
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An efficient molecular iodine-catalysed one-pot strategy has been accomplished for the construction of various fused heterocycles such as pyridoimidazoles, pyrrolo[1,2-a]quinoxalines and imidazobenzothiazoles under metal and oxidant free conditions. Gratifyingly, this method allows the sequential formation of C-N and C-C bonds with concomitant CO-C(alkyl) bond cleavage. The key features of this protocol are a broad substrate scope, operational simplicity, good to moderate yields and metal-free conditions, which make this protocol convenient for the generation of a library of fused polyheterocycles.
- Mani, Geeta Sai,Rao, Ayanampudi Venkata Subba,Tangella, Yellaiah,Sunkari, Satish,Sultana, Faria,Namballa, Hari Krishna,Shankaraiah, Nagula,Kamal, Ahmed
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p. 15820 - 15829
(2018/10/04)
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- Synthesis of novel imidazopyridines and their biological evaluation as potent anticancer agents: A promising candidate for glioblastoma
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Novel imidazopyridine derivatives were synthesized according to a very simple protocol and then subjected to cytotoxicity testing against LN-405 cells. Two of the compounds exhibited antiproliferative effects on LN-405 cells at 10 and 75 μM and were selected as lead compounds for further study. Safety experiment for lead compounds on WS1 was carried out and IC50 values were calculated as 480 and 844 μM. LN-405 cell line were incubated with the lead compounds and then tested for DNA damage by comet assay and effects on cell cycle using flow cytometry. The results of these two tests showed that both lead compounds affected the G0/G1 phase and did not allow the cells to reach the synthesis phase. The log BB (blood–brain barrier) and Caco-2 permeability of the synthesized molecules were calculated and it was shown that imidazopyridine derivatives taken orally are likely to pass through gastrointestinal membrane and the blood–brain barrier.
- Gü?lü, Dilek,Kuzu, Burak,Tozlu, ?srafil,Ta?p?nar, Filiz,Canp?nar, Hande,Ta?p?nar, Mehmet,Menges, Nurettin
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supporting information
p. 2647 - 2651
(2018/07/06)
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- Enantioselective Cyanosilylation of α,α-Dialkoxy Ketones by Using Phosphine-Thiourea Dual-Reagent Catalysis
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The first highly enantioselective cyanosilylation of α,α-dialkoxy ketones enabled by a dual-reagent catalysis has been developed. With the combination of a chiral bifunctional phosphine-thiourea and methyl acrylate, the key organophosphorus zwitterion intermediate was generated in situ as a novel Lewis base, which catalyzed the enantioselective cyanosilylation reaction in excellent yields (up to 99 %) with good-to-excellent enantioselectivities (up to 94 % ee).
- Yu, Qi-Wen,Wu, Lu-Ping,Kang, Tian-Chen,Xie, Jin,Sha, Feng,Wu, Xin-Yan
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supporting information
p. 3992 - 3996
(2018/07/31)
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- 9-Ethyl-3-{6-(het)aryl-[1,2,5]oxadiazolo[3,4-b]pyrazin-5-yl}-9H-carbazoles: synthesis and study of sensitivity to nitroaromatic compounds
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5-(9-Ethyl-9H-carbazol-3-yl)-substituted 6-(het)aryl[1,2,5]oxadiazolo[3,4-b]pyrazines were synthesized by direct transition metal-free C—H functionalization in the pyrazine ring. Their photophysical and sensory properties with respect to nitrobenzene and
- Verbitskiy,Kvashnin, Yu. A.,Baranova,Yakovleva, Yu. A.,Khokhlov,Rusinov,Charushin
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p. 1078 - 1082
(2018/10/02)
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- I2/Fe(NO3)3·9H2O-catalyzed oxidative synthesis of aryl carboxylic acids from aryl alkyl ketones and secondary benzylic alcohols
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An interesting and convenient procedure for the oxidative transformation of aryl alkyl ketones and secondary benzylic alcohols to aryl carboxylic acids has been developed. By using iodine and Fe(NO3)3·9H2O as the catalysts, DMSO and oxygen as the oxidants, the desired aryl carboxylic acids were synthesized in moderate to excellent yields (up to 91%).
- Xu, Liang,Chen, Yingying,Shen, Zhenlu,Wang, Yuru,Li, Meichao
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p. 4349 - 4354
(2018/11/03)
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- Iodine-Promoted One-pot Synthesis of Highly Substituted 4-Aminopyrroles and Bis-4-aminopyrrole from Aryl Methyl Ketones, Arylamines, and Enamines
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An iodine-promoted one-pot synthesis of functionally diverse and highly substituted 4-aminopyrroles directly from aryl methyl ketones, arylamines, and enamines was developed. The reaction involves in-situ oxidation of aryl methyl ketone to glyoxal, subsequent imine formation by aniline, followed by nucleophilic addition of enamine, and cyclization to afford highly substituted 4-aminopyrroles. This reaction involved the formation of two C?N bonds and one C?C bond by a formal [1+1+3] annulation approach. The present method provides an interesting framework of two 4-aminopyrrole units directly attached to a biphenyl core by the reaction of 4,4′-diacyl biphenyl, amine, and enamine groups. This Hantzsch-type one-pot reaction provides diverse 4-aminopyrroles, which could be useful in medicinal/material chemistry. (Figure presented.).
- Jalani, Hitesh B.,Mali, Jyotirling R.,Park, Hyejun,Lee, Jae Kyun,Lee, Kiho,Lee, Kyeong,Choi, Yongseok
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supporting information
p. 4073 - 4079
(2018/09/25)
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- Reactions of cyclohexyl isocyanide, dialkyl acetylenedicarboxylates and 1-aryl-2-ene-3-acetyl-1,4-diketones: One-pot synthesis of highly functionalized 5-cyclohexylimino-2,5-dihydrofurans
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Dihydrofurans are important intermediates in organic synthesis, and are also important starting materials used in syntheses of a number of natural products. A facile synthesis of highly functionalized 5- cyclohexylimino-2,5-dihydrofuran derivatives by the multi-component reaction of cyclohexyl isocyanide, dialkyl acetylenedicarboxylates and 1-aryl-2-ene-3-acetyl-1,4-diketones is described.
- Latifi, Mahsa,Talebdizaeh, Mahdiyeh,Anary-Abbasinejad, Mohammad
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