- Cycloaddition of bis-cyclohexa-2,4-dienones: Synthesis of novel carbocycles
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Syntheses of novel carbocycles (4) and (5) based on cycloaddition of bis-cyclohexa-2,4-dienone (3) and cyclopentadiene is reported. An improved method for the preparation of tetramethyl bisphenol-F (2), a precursor of bis-cyclohexa-2,4-dienone (3), is also presented.
- Singh, Deepak,Deota, Pradeep T.
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- Oxidative acetylation of tetramethyl bisphenol-F
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Oxidative acetylation of tetramethyl bisphenol-F (2) using two different reagents is described. The reaction of (2) with NaIO4 in acetic anhydride furnished a novel triacetate (3) and its reaction with lead tetraacetate (LTA) in dry benzene resulted in the formation of a novel bis-cyclohexadienone (4). Copyright Taylor & Francis Group, LLC.
- Deota, Pradeep T.,Parmar, Hemant S.,Valodkar, Vaibhav B.,Upadhyay, Piyush R.,Sahoo
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- Synthesis, oxidation and crosslinking of tetramethyl bisphenol F (TMBPF)-based polymers for oxygen/nitrogen gas separations
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Amorphous, high glass transition, crosslinkable poly(arylene ether)s for gas purification membranes have been synthesized. The polymers include a moiety capable of several oxidation reactions and UV crosslinking. Structural identification was confirmed by 1H NMR and IR spectroscopy and molecular weights were determined by SEC. Two oxidation reactions of the polymers were identified, one by chemical treatment using Oxone and KBr and one by elevated thermal treatment in air. DSC and TGA were used for thermal characterization, and TGA, 1H NMR and ATR-FTIR revealed the progress of the thermal oxidation reactions. Both polymers produced tough, ductile films and gas transport properties of the non-crosslinked linear polymers and crosslinked polymer are compared. The O2 permeability of one exemplary non-crosslinked poly(arylene ether) was 2.8 Barrer, with an O2/N2 selectivity of 5.4. Following UV crosslinking, the O2 permeability decreased to 1.8 Barrer, and the O2/N2 selectivity increased to 6.2.
- Sundell, Benjamin J.,Shaver, Andrew T.,Liu, Qiang,Nebipasagil, Ali,Pisipati, Priya,Mecham, Sue J.,Riffle, Judy S.,Freeman, Benny D.,McGrath, James E.
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- Development of Transition-Metal-Free Lewis Acid-Initiated Double Arylation of Aldehyde: A Facile Approach Towards the Total Synthesis of Anti-Breast-Cancer Agent
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This work describes a mild and robust double hydroarylation strategy for the synthesis of symmetrical /unsymmetrical diaryl- and triarylmethanes in excellent yields using Lambert salt (0.2–1.0 mol%). Despite the anticipated challenges associated with controlling selective product formation, unsymmetrical diaryl- and triarylmethanes products are obtained unprecedentedly. A highly efficient gram scale reaction has also been reported (TON for symmetrical product=475 and for unsymmetrical product=390). The synthetic utility of the methodology is demonstrated by the preparation of several unexplored diaryl- and triarylmethane-based biologically relevant molecules, such as arundine, vibrindole A, turbomycin B, and certain anti-inflammatory agents. A total synthesis of an anti-breast-cancer agent is also demonstrated. Control experiments, Hammett analysis, HRMS and GC-MS studies reveal the reaction intermediates and reaction mechanism.
- Singh, Sanjay,Mahato, Rina,Sharma, Pragya,Yadav, Naveen,Vodnala, Nagaraju,Kumar Hazra, Chinmoy
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supporting information
(2022/02/19)
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- Unusual transformation of 4-hydroxy/methoxybenzylic alcohols via C[sbnd]C ipso-substitution reaction using proton-exchanged montmorillonite as media
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We present here proton-exchanged montmorillonite-mediated an unusual transformation of 4-hydroxy and 4-methoxybenzylic alcohols to form symmetrical benzylic ethers and diarylmethanes under mild conditions. Nuclear magnetic resonance spectroscopy and density functional theory calculations support a plausible mechanism, which includes a distinctive aromatic C[sbnd]C ipso-substitution reaction with a hydroxymethyl group as the C-based leaving group.
- Chen, Dongyin,Chen, Xuan,Dong, Zezhong,Jiang, Nan,Li, Fei,Yun, Yangfang,Zhou, Yu
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supporting information
(2020/11/12)
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- Surface-accessible detection units in self-immolative polymers enable translation of selective molecular detection events into amplified responses in macroscopic, solid-state plastics
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This Communication describes a strategy for incorporating detection units onto each repeating unit of self-immolative CDr polymers. This strategy enables macroscopic plastics to respond quickly to specific applied molecular signals that react with the plastic at the solid-liquid interface between the plastic and surrounding fluid. The response is a signal-induced depolymerization reaction that is continuous and complete from the site of the reacted detection unit to the end of the polymer. Thus, this strategy retains the ability of CDr polymers to provide amplified responses via depolymerization while simultaneously enhancing the rate of response of CDr-based macroscopic plastics to specific applied signals. Depolymerizable poly(benzyl ethers) were used to demonstrate the strategy and now are capable of depolymerizing in the context of rigid, solid-state polymeric materials.
- Yeung, Kimy,Kim, Hyungwoo,Mohapatra, Hemakesh,Phillips, Scott T.
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supporting information
p. 5324 - 5327
(2015/05/13)
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- Aromatics to bis-triquinane: A tandem oxidative dearomatization of bis-phenol, cycloaddition, photorearrangement and a rapid entry into carbocyclic framework of Xeromphalinone e
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A novel approach for the synthesis of a bird-shaped bis-triquinane 3, a fascinating carbocyclic framework closely related to the skeleton of Xeromphalinone E 1 from readily available 2,6-dimethyl phenol 8 has been reported. The synthesis of bis-cyclohexadienones 6, 22a-e by oxidative acetylation of tetramethyl bisphenols 7, 20a-e has been investigated using two different reagents under varying reaction conditions. The cycloaddition of bis-cyclohexadienone 6 gives two carbocycles, bis-adduct 4b and mono-adduct 5d in a stereocontrolled manner. The photochemical sigmatropic 1,2-acyl shift in 4b furnished 3 and monotriquinane 9 linked with a 9-acetoxy-9-methyl-endo- tricyclo[5,2,2,02,6]undeca-4,10-diene-8-one system. Two different pentasubstituted phenols 13 and 14 were also isolated during an attempted oxa-di-π-methane (ODPM) rearrangement of mono-adduct 5d via aromatisation of the cyclohexadienone ring. The photochemical behaviour of bis-cyclohexadienones 6, 22a-e has also been investigated under UV irradiation and two different aromatized products were isolated for each bis-cyclohexadienone by migration and elimination of acetate groups.
- Singh, Deepak,Chaudhari, Umesh V.,Deota, Pradeep T.
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p. 4485 - 4493
(2014/06/10)
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- Crystal structures and isometricity comparison of methylated bisphenol F derivatives
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The syntheses and X-ray structures of three methylated bisphenol F derivatives and one respective analogue are reported. A special emphasis lies on the influence of methyl groups on the conformation of the common diphenylmethane scaffold. The introduction of four methyl groups to bisphenol F was found not to disturb its typical strong hydrogen bond network, and yet, to change the pattern of the aromatic interactions in the overall packing. According to the isometricity comparison, the addition of methyl groups to the diphenylmethane core has a greater influence on the conformation of the individual molecules, than the presence or absence of hydrogen bonding donors or acceptors.
- Gruber, Tobias,Nestler, Robert,Seichter, Wilhelm,Bombicz, Petra
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p. 319 - 325
(2013/12/04)
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- γ-hydroxypropylation of 2,6-dialkyl(aryl)phenols with allyl alcohol and its derivatives
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The composition of the products of the reaction of 2,6-disubstituted phenols with allyl alcohol and its derivatives in an alkaline medium was investigated, the conditions for carrying out the reaction with the predominant formation of 4-(3-hydroxypropyl)-2,6-dialkyl(aryl)phenols were found, and its mechanism was suggested. The reaction was examined on an industrial scale. An important result is the practical demonstration of alkaline catalysis performed under homogeneous conditions with participation of phenols, when the used alkaline catalyst is recovered in the process without the formation of waste waters. Pleiades Publishing, Ltd., 2010.
- Krysin,Khalikova,Khlebnikova,Nogina,Mamatyuk
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experimental part
p. 2290 - 2297
(2011/04/14)
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- The Chemistry of Novolac Resins. I A Review on the Use of Models
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The model systems ranging from the simple phenolic derivatives xylenol and cresol to higher oligomers such as (13), (15) and (17) are being used to study the chemistry of the curing of phenol-formaldehyde resins with hexamethylenetetramine.The key intermediates in these systems have been identified and this knowledge is being used to develop an understanding of the curing of the complex commercial resins.
- Looney, Mark G.,Solomon, David H.
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p. 323 - 332
(2007/10/02)
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- Carboxyalkylthiomethylation of Phenols
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The syntheses of carboxyalkylthiomethyl-substituted phenols, 2,4-, 2,6- and 3,5-xylenols and 2,3,5,6-tetramethylphenol are described.In all cases except 2,6-xylenol, a one-step process based on refluxing the phenol with formalin and the sodium salt of a mercaptoalkanoic acid gave products substituted in all of the vacant ortho and para positions.With 2,6-xylenol a two-step process was necessary.The products are of interest as potential inhibitors of ferrous corrosion.
- Massy, D. J. R.,McKillop, A.
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p. 253 - 255
(2015/06/03)
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- Migrations in Oxidations of Mesidine
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The oxidation of mesidine in methanolic media by ferricyanide, dichromate, and persulfate afforded an anil 4 containing a shifted methoxymethyl group in addition to the principal anil 3 formed by oxidative dealkylation.Possible intermediates 6, 7, and 8 were prepared and oxidized to the product anils.Oxidations of related anilines 9, 10, and 13 did not parallel those of mesidine but afforded analogues of 3.There is significant spectral evidence for anils with alkyl shifts but little for anils analogous to 4.
- Goldstein, Stephen L.,McNelis, Edward
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p. 1613 - 1620
(2007/10/02)
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- Synthesis and Reactions of Phenolic Alkylbenzylnitrosamines
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N-Alkyl-p-hydroxybenzylnitrosamines have been synthesised from p-benzoyloxybenzaldehydes via imines and amines which were nitrosated before removal of the protecting group with n-propylamine.N-Alkyl-o-hydroxybenzylnitrosamines were similarly obtained from o-methoxymethoxybenzaldehydes, the final deprotection being achieved with dilute acid.The nitrosamines decompose in hot aqueous alkali by two mechanisms, one through a quinone methide to yield a benzyl alcohol and the other by an elimination eventually yielding a benzaldehyde.The decomposition of the nitrosamines in the presence of 2-naphthol in alkaline solution results in alkylation of the naphthol and production of compounds from the reaction of 2-naphthol with the intermediate quinone methides.The N-sec-butylnitrosamines alkylate 2-naphthol on carbon but the N-methylnitrosamines alkylate on oxygen and during the methylation 94percent of deuterium exchange with methyl hydrogen occurs in deuterium oxide and there is 6percent intact transfer of the methyl group from the N-methylnitrosamine to the 2-naphthol.
- Bowman, Peter J.,Brown, Ben R.,Chapman, M. Andrew,Doyle, Paul M.
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p. 701 - 770
(2007/10/02)
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- Novel polytriazine compounds
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Novel tetraalkyl piperidine radical containing polytriazine compounds are produced by reacting a dihalogen-triazine with a bifunctional compound containing amine, alcohol, mercaptan or phenol groups at least one of the bifunctional compounds containing a tetraalkyl piperidine radical. The compounds are valuable light stabilizers for synthetic polymers, particularly polyolefin in the form of fibers or films.
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