Showing papers on "Alkoxy group published in 2019"
TL;DR: This feature article summarizes the recent achievements in (a) C(sp3)-C(Sp3) bond cleavage via ring-opening of cycloalkanols and (b) site-specific C( sp3)-H functionalization of unprotected aliphatic alcohols, along with the reconstruction of various new chemical bonds, e.g. C-halogen, C-C,C-N, C -S, and C-Se bonds.
121 citations
TL;DR: A series of 1,8-diazabicyclo-[5.4.0]undec-7-ene based bifunctional protic ionic liquids (DBPILs) were used to catalyze the cycloaddition reaction of CO2 with epoxides under mild conditions.
88 citations
TL;DR: A manganese-catalyzed electrochemical deconstructive chlorination of cycloalkanols exhibits a broad substrate scope, with various cyclopropanols and cyclobutanols converted into synthetically useful β- and γ-chlorinated ketones.
65 citations
TL;DR: In this paper, a long alkoxy substituted polythiohene poly[3-(2-(2-2-(diethanolamino)ethoxy),ethoxy)thoxy,ethoxy)-thiophene (PD4ET) was chemically grafted to the graphene oxide (GO) nanosheets via esterification reaction to give a novel PD4ET-g-GO nanocomposite.
64 citations
TL;DR: In this paper, four new groups of 4-((2ʹ-substitutedphenylimino)methyl)phenyl-4”-alkoxy benzoates, Ina-d, of Schiff base ester liquid crystals, were prepared and investigated for their mesophase formation and stability.
Abstract: Four new groups of 4-((2ʹ-substitutedphenylimino)methyl)phenyl-4”-alkoxy benzoates, Ina-d, of Schiff base ester liquid crystals, were prepared and investigated for their mesophase formation and stability. Each group constitutes four homologous series that differ from each other by the lateral attached polar group X in the ortho position for the imine mesogen at terminal benzene ring that alternatively changed from F, Br, NO2 and lateral benzene ring. Within each homologous series, the number (n) of carbons in the alkoxy chain varies between 6, 8, 10 and 12. Molecular structures of the prepared compounds were confirmed via elemental analysis, FT-IR, and 1H NMR spectroscopy. Mesomorphic properties were investigated by differential scanning calorimetry (DSC) and the phase identified by polarised light microscopy (PLM). A comparative study was made between the investigated compounds and their previously prepared laterally neat, 4-((4ʹ-phenylimino)methyl)phenyl-4”-alkoxy benzoates (IIn); the result rev...
56 citations
TL;DR: In this paper, mesomorphic and optical properties of new angular chalcone liquid crystals, 4-(1,5-(3-oxopenta-1,4-dienyl))diphenyl bis-4-alkoxybenzoates, were investigated.
53 citations
TL;DR: In this article, four new groups of Schiff base ester liquid crystal compounds, 4-(arylideneamino)phenyl-4″-alkoxy benzoates, Ina-d, were prepared and investigated for their mesophase formation and stability.
50 citations
TL;DR: For the first time the synthesis of NH-sulfonimidamides is achieved directly from sulfenamides, themselves readily formed in 1 step from amines and disulfides, in addition to water and acetate.
Abstract: Sulfonimidamides are intriguing new motifs for medicinal and agrochemistry, and provide attractive bioisosteres for sulfonamides. However, there remain few operationally simple methods for their preparation. Here, the synthesis of NH-sulfonimidamides is achieved directly from sulfenamides, themselves readily formed in one step from amines and disulfides. A highly chemoselective and one-pot NH and O transfer is developed, mediated by PhIO in iPrOH, using ammonium carbamate as the NH source, and in the presence of 1 equivalent of acetic acid. A wide range of functional groups are tolerated under the developed reaction conditions, which also enables the functionalization of the antidepressants desipramine and fluoxetine and the preparation of an aza analogue of the drug probenecid. The reaction is shown to proceed via different and concurrent mechanistic pathways, including the formation of novel S≡N sulfanenitrile species as intermediates. Several alkoxy-amino-λ6 -sulfanenitriles are prepared with different alcohols, and shown to be alkylating agents to a range of nucleophiles.
49 citations
TL;DR: In this article, a series of highly branched amorphous polymers containing poly(1,3-dioxolane) (PDXL) in the branches, which interacts favorably with CO2 but not N2, are reported.
46 citations
18 Jun 2019
TL;DR: A study on the transient absorption of these complexes demonstrated that they all possessed broadband triplet excited-state absorption in the 400-800 nm region, the largest reported for an Ir(III) complex photosensitizer upon broadband visible light (400-700 nm) activation.
Abstract: Six homo- or heteroleptic tricationic Ir(R1-tpy)(R2-tpy)3+ complexes (Ir1–Ir6, R1/R2 = Ph, 4′-N(CH3)2Ph, pyren-1-yl, or 4′-{2-[2-(2-methoxyethoxy)ethoxy]ethoxy}Ph, tpy = 2,2′;6′,2″-terpyridine) wer...
43 citations
TL;DR: A cation radical-accelerated-nucleophilic aromatic substitution (CRA-SNAr) of alkoxy arenes utilizing a highly oxidizing acridinium photoredox catalyst and acetone cyanohydrin, an inexpensive and commercially available cyanide source is described.
TL;DR: New non-symmetrical homologues series of Schiff base/ester series, 4-alkoxyphenylimino-4-phenyl-4ʹ’-alkoxybenzoates, have two terminal alkoxy groups (Im/n) were synthesized and investigated for t...
Abstract: New non-symmetrical homologues series of Schiff base/ester series, 4-alkoxyphenylimino-4ʹ-phenyl-4ʹ’-alkoxybenzoates, have two terminal alkoxy groups (Im/n), were synthesised and investigated for t...
TL;DR: The generation of alkoxy radicals from N-alkoxyazinium or azolium salts, occurring via the facile mono-electronic photocatalytic reduction of the starting compounds, has been recently reported.
TL;DR: In this paper, 10 laterally chloro azopyridine-based derivatives with terminal alkoxy chain length varies between 6 and 16 carbons, with mesophase behavior investigated.
Abstract: New 10 laterally chloro azopyridine-based derivatives, with terminal alkoxy chain length varies between 6 and 16 carbons, were prepared. The mesophase behaviour was investigated for prepare...
TL;DR: In this paper, the mesomorphic behavior of hydrogen-bonded liquid crystals (HBLCs) between a 4-n-alkylthiobenzoic acid homologous series and a 4,4-bipyridine at each ratio of 2/1 (mol/mol) was investigated.
TL;DR: In this article, a predictive model was developed that captures quantitative structure-property relationships between the molecular structures of surfactants and co-solvents and micro-emulsion phase behavior.
TL;DR: Kinetically, oxygen vacancies induced by Rh3+ substitution in the SrTiO3 lattice not only favor the dissociative adsorption of alcohols yielding alkoxy species but also induce the weakening of the α-C-H bond facilitating its cleavage by the photogenerated holes.
Abstract: Photocatalytic oxidation of organic compounds on semiconductors provides a mild approach for organic synthesis and solar energy utilization. Herein, we identify the key points for the photocatalytic oxidation over Pt-loaded Rh-doped strontium titanate allowing the conversion of alcohols efficiently and selectively to aldehydes and ketones under anaerobic conditions and visible light with an apparent quantum efficiency of pure benzyl alcohol oxidation at 420 nm of ≤49.5%. Mechanistic investigations suggest that thermodynamically the controlled valence band edge position via Rh doping provides a suitable oxidation ability of photogenerated holes, avoiding the powerful hydroxyl radical intermediates prone to overoxidation resulting in high selectivity. Kinetically, oxygen vacancies induced by Rh3+ substitution in the SrTiO3 lattice not only favor the dissociative adsorption of alcohols yielding alkoxy species but also induce the weakening of the α-C-H bond facilitating its cleavage by the photogenerated holes. Pt nanoparticles deposited as a cocatalyst contribute to the final hydrogen evolution.
TL;DR: In this paper, a chair-shaped liquid crystalline complexes were formed through intermolecular hydrogen bonding between 4-(4-(hexyloxyphenylimino)methyl)phenyl nicotinate and 4-alkoxybenzoic acids, with different alkoxy chains.
Abstract: A new series of chair-shaped liquid crystalline complexes were formed through 1 : 1 intermolecular hydrogen bonding between 4-(4-(hexyloxyphenylimino)methyl)phenyl nicotinate and 4-alkoxybenzoic acids, with different alkoxy chains. The mesomorphic behaviour of these supramolecular hydrogen-bonded complexes was investigated through differential scanning calorimetry and polarizing optical microscopy. The Fermi bands of the hydrogen bonding formation were confirmed through Fourier-transform infrared spectroscopy. Schlieren textures of the nematic phase (N) were observed for all prepared complexes. These thermotropic supramolecular complexes were confirmed also using density functional theory calculations. It was found that as the akoxy chain length increased the predicted total energy of the H-bonded complex also increased. The predicted data of the charge distribution explained the nematic mesophase which covered all 1 : 1 mixtures and it could be attributed to more end-to-end aggregations of the alkoxy chains with longer chain lengths. Moreover, formation of the H-bonded complexes greatly affected polarizability with respect to the individual compounds. The polarizability increased three and one third times compared with that of the free acid and base, respectively.
TL;DR: The amide moiety of the aldol adduct was transformed into a variety of functional groups without protection of the tertiary alcohol, showcasing the synthetic utility of the present asymmetric aldl process.
Abstract: α-Oxygen-functionalized amides found particular utility as enolate surrogates for direct aldol couplings with α-fluorinated ketones in a catalytic manner. Because of the likely involvement of open transition states, both syn- and anti-aldol adducts can be accessed with high enantioselectivity by judicious choice of the chiral ligands. A broad variety of alkoxy substituents on the amides and aryl and fluoroalkyl groups on the ketone were tolerated, and the corresponding substrates delivered a range of enantioenriched fluorinated 1,2-dihydroxycarboxylic acid derivatives with divergent diastereoselectivity depending on the ligand used. The amide moiety of the aldol adduct was transformed into a variety of functional groups without protection of the tertiary alcohol, showcasing the synthetic utility of the present asymmetric aldol process.
TL;DR: Surprisingly, C4MeImAc-DMSO was more efficient than C3OMeIm Ac-D MSO for the dissolution and acylation of cellulose, and is attributed to "deactivation" of the ether oxygen and C2H of the imidazolium ring due to intramolecular hydrogen bonding.
TL;DR: In this paper, different alkoxy groups were introduced to modify the structure of commercial Spiro-OMeTAD to give new Spiro derivatives of Spiro OEtTAD, Spiro OPrTAD and OOiPrTAD with the aim to adjust the molecular packing status in perovskite solar cells as hole transporting compounds.
Abstract: By intelligently utilizing the odd-even effect existing in the melting points of alkanes as presented in the basic textbook of Organic Chemistry, different alkoxy groups were introduced to modify the structure of commercial Spiro-OMeTAD to give new Spiro derivatives of Spiro-OEtTAD, Spiro-OPrTAD, Spiro-OiPrTAD and Spiro-OBuTAD, with the aim to adjust the molecular packing status in perovskite solar cells as hole transporting compounds. Excitedly, with the introduction of ethoxy groups instead of the methoxy ones in Spiro-OMeTAD, Spiro-OEtTAD-based perovskite solar cells demonstrated the highest device performance of 20.16%, higher than that of Spiro-OMeTAD (18.64%).
TL;DR: An oxidative ring-opening strategy to transform acyl, sulfonyl or carbamate protected aminocyclopropanes into 1,3-dielectrophilic carbon intermediates bearing a halide atom (Br, I) and a N,O-acetal is reported, generating a wide range of 1, 3-difunctionalized propylamines.
Abstract: We report an oxidative ring-opening strategy to transform acyl, sulfonyl or carbamate protected aminocyclopropanes into 1,3-dielectrophilic carbon intermediates bearing a halide atom (Br, I) and a N,O-acetal. Replacing the alkoxy group of the N,O-acetal can be achieved under acidic conditions through an elimination-addition pathway, while substitution of the halides by nucleophiles can be done under basic conditions through a SN 2 pathway, generating a wide range of 1,3-difunctionalized propylamines. A proof of concept for asymmetric induction was realized using a chiral phosphoric acid (CPA) as catalyst, highlighting the potential of the method in enantioselective synthesis of important building blocks.
TL;DR: In this paper, an electrochemical vicinal heterodifunctionalization of olefins for the synthesis of β-oxysulfones is described, with suitable choice of the conditions, including current, electrodes, and electrolyte, this oxidation reaction proceeded efficiently in an undivided cell without the use of a stoichiometric chemical oxidant.
TL;DR: In this paper, a mechanistic study showed that the reaction proceeds through a rate-determining C-H bond cleavage, accompanied by an unexpected N-O bond cleaving.
Abstract: Palladium-catalyzed C–H/N–H functionalization of easily prepared N-alkoxy benzsulfonamides with arynes provides dibenzosultams in good yields via C–C/C–N bond formation, accompanied by an unexpected N–O bond cleavage. A mechanistic study shows that the reaction proceeds through a rate-determining C–H bond cleavage.
TL;DR: In this paper, the authors used ultrasound to fabricate a highly hydrophobic aluminium surface in a one-step ultrasound process in a sodium hydroxide solution containing various alkoxysilanes.
Abstract: This study aimed to fabricate a highly hydrophobic aluminium surface in a one-step ultrasound process in a sodium hydroxide solution containing various alkoxysilanes. The latter were based on the trimethoxysilane of various type and length of the introducing group at the silyl bond (Si C): Ra-Si(OMe)3 and Rf-(CH2)2-Si(OMe)3, where Ra and Rf are alkyl and perfluoroalkyl introducing groups, respectively, and OMe is the methoxy group. The effect of methoxy and ethoxy groups at the siloxy bond was additionally investigated for perfluorodecyl silanes. The corrosion performance was studied using potentiodynamic electrochemical techniques. The wettability, morphology, surface topography and surface composition of treated aluminium surfaces were characterised using an optical tensiometer, a scanning electron microscope coupled with an energy dispersive X-ray spectrometry system, a contact profilometer and a Fourier transform infrared spectroscopy system. Micro-/nanostructures formed on the treated aluminium surfaces lead to an increase in the water contact angle from 71° for ground surface, up to 115° for the surface treated with alkyl silanes and up to 155° for that treated with fluoroalkyl silanes with a long chain. The superhydrophobic coatings show corrosion-resistant behaviour in chloride solution, while the durability in slightly acidic/alkaline solutions indicates the excellent water-repellent nature of the coatings, the self-cleaning ability for different types of pollutants and improved anti-icing properties with freezing and melting delay.
TL;DR: A novel and efficient metal- and solvent-free regioselective para-C-H cyanation of hydroxy-, alkoxy-, and benzyloxyarene derivatives has been introduced, using nontoxic potassium thiocyanate as a cyanating reagent in the presence of silica sulfuric acid.
Abstract: A novel and efficient metal- and solvent-free regioselective para-C–H cyanation of hydroxy-, alkoxy-, and benzyloxyarene derivatives has been introduced, using nontoxic potassium thiocyanate as a cyanating reagent in the presence of silica sulfuric acid (SSA). The desired products are obtained in good to high yields without any toxic byproducts.
TL;DR: A broad range of α-diazoesters with different substituents and various N,O-aminals were compatible with this protocol, affording the corresponding α-alkoxy-β-amino acid esters in good to excellent yields.
TL;DR: In this paper, a nickel catalyst was used to achieve C(sp2)-H borylation of arenes, resulting in a good yield and the formation of Ni nanoparticles (Ni-NPs), which act as catalytically active species.
TL;DR: Pt-catalyzed regioselective diboration of alkoxyallene or aminoallene with B2pin2 occurred at the terminal alkene unit of the allene to give TES-protected syn-1,2-diols and syn-2-amino alcohols with high diastereoselectivities.
TL;DR: In this article, density functional theory was employed to explore mechanistic aspects of BF3-catalyzed alcohol oxidation using a hypervalent iodine(III) compound, [ArI(OAc)2], to yield aldehydes/ketones as the final products.
Abstract: Density functional theory (DFT) at the SMD/M06-2X/def2-TZVP//SMD/M06-2X/LANL2DZ,6-31G(d) level was employed to explore mechanistic aspects of BF3-catalyzed alcohol oxidation using a hypervalent iodine(III) compound, [ArI(OAc)2], to yield aldehydes/ketones as the final products. The reaction is composed of two main processes: (i) ligand exchange and (ii) the redox reaction. Our study for 1-propanol discovered that ligand exchange is preferentially accelerated if BF3 first coordinates to the alcohol. This coordination increases the acidity of the alcohol hydroxyl proton, resulting in ligand exchange between the iodane and the alcohol proceeding via a concerted interchange associative mechanism with an activation free energy of ∼10 kcal/mol. For the redox process, the calculations rule out the feasibility of the conventional mechanism (alkoxy Cα deprotonation) and introduce a replacement for it. This alternative route commences with α-hydride elimination of the alkoxy group promoted by BF3 coordination, which yields a BF3-stabilized aldehyde/ketone product and the iodane [ArI(OAc)(H)]. The ensuing iodane is extremely reactive toward reductive elimination to give ArI + HOAc in a highly exergonic fashion (ΔG = −62.1 kcal/mol). The reductive elimination reaction is the thermodynamic driving force for the alcohol oxidation to be irreversible. Consistent with the kinetic isotope effect reported experimentally, the α-hydride elimination is calculated to be the rate-determining step with an overall activation free energy of ∼24 kcal/mol.