- Cyclopropeniminium Ions Exhibit Unique Reactivity Profiles with Bioorthogonal Phosphines
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We report a new ligation of cyclopropeniminium ions with bioorthogonal phosphines. Cyclopropeniminium scaffolds are sufficiently stable in biological media and, unlike related isomers, react with functionalized phosphines via formal 1,2-addition to a I-system. The ligation can be performed in aqueous solution and is compatible with existing bioorthogonal transformations. Such mutually compatible reactions are useful for multicomponent labeling.
- Heiss, Tyler K.,Prescher, Jennifer A.
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- Fully Substituted Conjugate Benzofuran Core: Multiyne Cascade Coupling and Oxidation of Cyclopropenone
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An unprecedented C═C double bond cleavage of cyclopropenone and dioxygen activation by multiyne cascade coupling has been developed. This chemistry provides a novel, simple, and efficient approach to synthesize fully substituted conjugate benzofuran derivatives from simple substrates under mild conditions. The density functional theory (DFT) calculations reveal that the unique homolytic cleavages of cyclopropenone and molecular oxygen are crucial to the success of this reaction.
- Yao, Liangliang,Hu, Qiong,Bao, Li,Zhu, Wenjing,Hu, Yimin
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p. 4971 - 4975
(2021/06/30)
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- Synthesis, characterization, and oxidation electrochemistry of some novel 1,2-dithiol-3-ones and 1,2-dithiol-3-thiones containing aryl and metallocenyl fragments
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A new synthesis method was established for 1,2-dithiol-3-ones and 1,2-dithiol-3-thiones, from different cyclopropenones: diphenyl (a), bis-(4-methoxyphenyl (b), diferrocenyl (c) and diruthenocenyl (d), in the presence of elemental sulfur with yields of the 5a-d (35–57%), or in the presence of the additive NaHS, with yields of the 5a-d (45–72%) and 6a-d (10–18%). The characterization of the new compounds was conducted by IR, 1H and 13C NMR spectroscopy, elemental analysis, mass-spectrometry. In addition, X-ray crystallographic analysis of the compounds 5a,b,d was conducted. The redox properties of the heterocyclic compounds were investigated using cyclic (CV), differential pulse (DPV) and square wave (SWV) voltammetries.
- Sánchez García, Jessica J.,Joo-Cisneros, Rene S.,García-Bassoco, David,Flores-Alamo, Marcos,Stivalet, José M. Méndez,García-Valdés, Jesús,Klimova, Elena I.
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- Palladium-Catalyzed C-C Bond Activation of Cyclopropenone: Modular Access to Trisubstituted α,β-Unsaturated Esters and Amides
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Strain-driven palladium/N-heterocyclic carbene-catalyzed C-C bond activation of diphenylcyclopropenone (DPC) has been explored for one-step access to trisubstituted α,β-unsaturated esters and amides. The designed transformation works under mild conditions providing exclusively a single stereoisomer. Mechanistic studies support the oxidative addition of the C-C bond of cyclopropenone to in-situ-generated Pd(0) intermediate. We have proved that vinylic hydrogen in the product is coming from phenol/aniline through deuterium-labeling studies. Late-stage functionalization of bioactive molecules such as procaine, estrone, and hymecromone demonstrates the robustness of this protocol.
- Nanda, Tanmayee,Biswal, Pragati,Pati, Bedadyuti Vedvyas,Banjare, Shyam Kumar,Ravikumar, Ponneri Chandrababu
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p. 2682 - 2695
(2021/02/01)
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- Rh(III)-Catalyzed [3 + 3] Annulation Reaction of Cyclopropenones and Sulfoxonium Ylides toward Trisubstituted 2-Pyrones
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A new Rh(III)-catalyzed [3 + 3] annulation reaction between cyclopropenones and β-ketosulfoxonium ylides has been reported, enabling metal carbene insertion to access a wide range of trisubstituted 2-pyrones with moderate to excellent yields via C-C single-bond cleavage, in which sulfoxonium ylides serve as potential safe precursors of metal carbenes. This reaction occurred under redox-neutral conditions with a broad substrate scope.
- Zhou, Peng,Yang, Wei-Tao,Rahman, Anis Ur,Li, Guigen,Jiang, Bo
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p. 360 - 366
(2019/11/14)
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- A Palladium-Catalyzed Cascade C-C Activation of Cyclopropenone and Carbonylative Amination: Easy Access to Highly Functionalized Maleimide Derivatives
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We describe herein the first report on palladium-catalyzed C-C bond activation of cyclopropenone and concomitant carbonylative amination to produce maleimides. The interesting aspect of this reaction is that the sacrificial elimination of carbon monoxide from the substrate is efficiently recaptured by one of the intermediates in the catalytic cycle for the formation of maleimides. 18O isotopic studies confirmed that the source of carbon monoxide is from cyclopropenone.
- Nanda, Tanmayee,Ravikumar, P. C.
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supporting information
(2020/02/15)
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- Cyclopropenium-Activated DMSO for Swern-Type Oxidation
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Swern oxidation is widely used to convert alcohols into their corresponding carbonyl compounds. However, the conventional method with use of the volatile oxalyl chloride as an activator requires the reaction to be conducted below -60 °C. We discovered that 3,3-dichloro-1,2-diphenylcyclopropene (DDC) can be used as a new activator for Swern-type oxidations of alcohols, which can be conducted at -20 °C. This new protocol features mild and fast reactions with easy operation. Furthermore, the activator DDC is easy to handle, and diphenylcyclopropenone can be recovered quantitively. This new type of Swern oxidation shows a broad scope of substrates including benzylic, allylic, aliphatic, and biobased alcohols, and gives high yields of up to 93%.
- Guo, Tianfo,Gao, Yu,Li, Zhenjiang,Liu, Jingjing,Guo, Kai
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supporting information
p. 329 - 332
(2019/02/12)
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- Organocatalytic Regiodivergent C?C Bond Cleavage of Cyclopropenones: A Highly Efficient Cascade Approach to Enantiopure Heterocyclic Frameworks
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Here a highly efficient cascade approach is reported that combines a cycloaddition reaction with a regioselective strain-release process to afford diverse heterocyclic frameworks through bifunctional catalysis. The cooperation of hydrogen-bonding network activation and a regiodivergent strain-assisted effect is the key to promoting this complex chemical transformation, leading to the generation of two different ring systems in high yields with excellent stereoselectivities. The reaction proceeded by a mechanism involving a “spring-loaded” intermediate with switchable C?C bond cleavages achieved by controllable ring-strain release. This reaction was also amenable to gram scale synthesis with only 0.1 mol % catalyst loading.
- Cao, Jian,Fang, Ran,Liu, Jin-Yu,Lu, Hong,Luo, Yong-Chun,Xu, Peng-Fei
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p. 18863 - 18867
(2018/11/23)
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- Organocatalyzed [3 + 2] Annulation of Cyclopropenones and β-Ketoesters: An Approach to Substituted Butenolides with a Quaternary Center
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An unprecedented organocatalyzed [3 + 2] annulation of cyclopropenones and β-ketoesters has been developed. This reaction provides a direct approach to highly substituted butenolides with a quaternary center in moderate to good yields. The preliminary mechanism study verified that the enol intermediate is crucial to the reaction outcome and the intermolecular esterification and intramolecular Michael addition process were involved.
- Li, Xuanyi,Han, Chunhua,Yao, Hequan,Lin, Aijun
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p. 778 - 781
(2017/03/01)
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- Cyclopropenone catalyzed substitution of alcohols with mesylate ion
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The cyclopropenone catalyzed nucleophilic substitution of alcohols by methanesulfonate ion with inversion of configuration is described. This work provides an alternative to the Mitsunobu reaction that avoids the use of azodicarboxylates and generation of hydrazine and phosphine oxide byproducts. This transformation is shown to be compatible with a range of functionality. A cyclopropenone scavenge strategy is demonstrated to aid purification.
- Nacsa, Eric D.,Lambert, Tristan H.
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supporting information
p. 38 - 41
(2013/03/28)
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- Alkyne and reversible nitrile activation: N, N'-diamidocarbene-facilitated synthesis of cyclopropenes, cyclopropenones, and azirines
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We report the synthesis of a variety of diamidocyclopropenes by combining an isolable and readily accessible N,N'-diamidocarbene (DAC) with a range of alkynes (nine examples, 68-97% yield). Subsequent hydrolysis of selected cyclopropenes afforded the corresponding cyclopropenones or α,β- unsaturated acids, depending on the reaction conditions. In addition, the combination of a DAC with alkyl or aryl nitriles was found to form 2H-azirines in a reversible manner (four examples, Keq = 4-72 M-1 at 30 °C in toluene).
- Moerdyk, Jonathan P.,Bielawski, Christopher W.
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supporting information; experimental part
p. 6116 - 6119
(2012/05/07)
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- Cyclopropenium-activated cyclodehydration of diols
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The dehydrative cyclization of diols to cyclic ethers via cyclopropenium activation is described. Using 2,3-diphenylcyclopropene and methanesulfonic anhydride, a series of 1,4-and 1,5-diols are rapidly cyclized to furnish tetrahydrofurans and tetrahydropyrans in high yield. Eleven total substrates are shown, including a gram scale cyclization of a diterpene derivative.
- Kelly, Brendan D.,Lambert, Tristan H.
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supporting information; experimental part
p. 740 - 743
(2011/05/04)
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- Nucleophilic acyl substitution via aromatic cation activation of carboxylic acids: Rapid generation of acid chlorides under mild conditions
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The first example of aromatic cation-activated nucleophilic acyl substitution has been achieved. The conversion of carboxylic acids to their corresponding acid chlorides occurs rapidly in the presence of 3,3-dichlorocyclopropenes via the intermediacy of cyclopropenium carboxylate complexes. The effect of cyclopropene substituents on the rate of conversion is examined. The addition of tertiary amine base is found to dramatically accelerate reaction, and conditions were developed for the preparation of acid sensitive acid chlorides. Preparative scale peptide couplings of two N-Boc amino acids were achieved with this method.
- Hardee, David J.,Kovalchuke, Lyudmila,Lambert, Tristan H.
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supporting information; experimental part
p. 5002 - 5003
(2010/06/13)
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- Aromatic cation activation of alcohols: Conversion to alkyl chlorides using dichlorodiphenylcyclopropene
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(Chemical Equation Presented) A novel paradigm for the activation of alcohols toward nucleophilic displacement via formation of cyclopropenium ethers is described. The conversion of a range of alcohol substrates to the corresponding alkyl chlorides occurs rapidly upon treatment with 3,3-dichloro-1,2-diphenylcyclopropene. 1H NMR data support the intermediacy of a cyclopropenium intermediate, and the reaction is demonstrated to proceed primarily via the SN2 mechanism for 1-phenylethanol. A total of 12 examples of substrate scope are provided.
- Kelly, Brendan D.,Lambert, Tristan H.
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supporting information; experimental part
p. 13930 - 13931
(2009/12/25)
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- PROCESS FOR PRODUCING DIALKYL CARBONATE AND DIOL
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A method for producing a dialkyl carbonate and a diol, comprising: (a) effecting a transesterification reaction between a cyclic carbonate and an aliphatic monohydric alcohol in the presence of a transesterification catalyst, thereby obtaining a reaction mixture containing a product dialkyl carbonate and a product diol, (b) withdrawing a dialkyl carbonate-containing liquid from the reaction mixture, followed by separation of the dialkyl carbonate from the dialkyl carbonate-containing liquid, and (c) withdrawing a diol -containing liquid from the reaction mixture, followed by separation of the diol from the diol-containing liquid, wherein the cyclic carbonate contains a cyclic ether in an amount of from 0.1 to 3,000 ppm by weight, and the product dialkyl carbonate contains a carbonate ether of not more than 10,000 ppm by weight.
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- Process for producing aromatic carbonate
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A process for producing an aromatic carbonate by reacting an aromatic monohydroxy compound with carbon monoxide and molecular oxygen, wherein the reaction is carried out in the presence of: (a) palladium or a palladium compound (component (a)); (b) a redox catalyst (component (b)); (c) a heteropoly-acid or salt thereof (component (c)); and (d) a quaternary ammonium salt or quaternary phosphonium salt (component (d)), and under dehydration conditions. According to the present invention, an aromatic carbonate can be produced from an aromatic monohydroxy compound by a simple process economically and efficiently.
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- Method of separating and recovering aromatic carbonate and production process
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A method of isolating and recovering an aromatic carbonate, in which a solvent having a solubility parameter of 7 to 10 is added to a solution of the aromatic carbonate in an aromatic hydroxy compound to precipitate the aromatic carbonate in the form of a crystal and the aromatic carbonate is isolated and recovered. According to the present invention, there is provided an advantageous method in which a high-purity aromatic carbonate in the form of a solid can be isolated from a reaction mixture solution obtained by reacting an aromatic hydroxy compound with carbon monoxide and molecular oxygen in the presence of a catalyst. Further, a method of recovering a catalyst and a method of recycling the catalyst are provided.
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- CATALYST AND PROCESS FOR THE PREPARATION OF AROMATIC CARBONATES
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Aromatic carbonates can be prepared economically and efficiently by reacting an aromatic hydroxy compound with carbon monoxide and oxygen in the presence of a catalyst wherein a palladium compound is supported on a perovskite-type composite oxide represented by the following formula (1) or (1′): M(1-x)M′xM″Oy??(1) (wherein, M is a group IIIB metal; x is a number of 0 to 1; M′ is a metal having an ionic radius of 0.90 ? or more; M″ is Mn, Cr, Co, Fe, Ni or Cu;y is a number of 2.5 to 3.5), or L(1-x)L′xL″Oy??(1′) (wherein, L is a group IIA or IVA metal taking a divalent state in the form of an oxide; x is a number of 0 to 1; L′ is a metal having an ionic radius of 0.90 ? or more; L″ is a group IVA, IVB or IIIB metal taking a tetravalent state in the form of an oxide; y is a number of 2.5 to 3.5), and the palladium accounts for 0.01 to 15% of the catalyst by weight.
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- PROCESS FOR THE PRODUCTION OF DIARYL CARBONATES
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A process for catalytic production of diaryl carbonates by oxidative carbonylation of aromatic hydroxy compounds with carbon monoxide and oxygen achieves water removal during reaction by a process comprising the steps of: removing a liquid stream from an oxidative carbonylation reaction mixture in a reaction vessel, subjecting the liquid stream to reduced pressure, and returning at least a portion of dried liquid stream to the reaction vessel. Typical catalyst systems for oxidative carbonylation contain (A) at least one Group 8, 9, or 10 metal having an atomic number of at least 44 or a compound thereof; (B) at least one alkali metal salt; (C) at least one metal co-catalyst; (D) at least one activating organic solvent; and (E) optionally, at least one base.
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- Process for the production of diaryl carbonates
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A process for catalytic production of diaryl carbonates by oxidative carbonylation of aromatic hydroxy compounds with carbon monoxide and oxygen achieves water removal during reaction by a process comprising the steps of: removing a liquid stream from an oxidative carbonylation reaction mixture in a reaction vessel, subjecting the liquid stream to reduced pressure, and returning at least a portion of dried liquid stream to the reaction vessel. Typical catalyst systems for oxidative carbonylation contain (A) at least one Group 8, 9, or 10 metal having an atomic number of at least 44 or a compound thereof; (B) at least one alkali metal salt; (C) at least one metal co-catalyst; (D) at least one activating organic solvent; and (E) optionally, at least one base.
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- Skin patch for use in contact immunotherapy
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A device, preferably in the form of a skin patch, is disclosed for usage in the delivery of a contactant to human skin for the purpose of treating medical conditions responsive to contact immunotherapy, without the presence of medication to alleviate contact dermatitis induced by the contactant. The skin patch specifically induces a cell-mediated contact dermatitis in the treatment of skin disorders. Its anticipated use pertains to treatment of, for example, human papilloma virus infections, or warts. In a first embodiment, a pressure activated single chambered skin patch is topically applied and used for controlled release of contactant to human skin. In a second embodiment, a pressure activated two-chambered skin patch is topically applied and used for controlled release of a contactant to human skin. Alternatively, a single chambered skin patch is topically applied and hydrated by the contacted skin for release of contactant. In an additional embodiment, the contactant may be applied separately of the skin patch portion, in a manner that maintains the contactant in contact with the patient's skin for the predetermined period of time necessary to cause sufficient contact dermatitis to effect resolution of the medical condition.
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- PROCESS FOR THE PREPARATION OF AROMATIC POLYCARBONATE
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A process for producing an aromatic polycarbonate through an ester interchange reaction between an aromatic carbonic acid diester and an aromatic dihydroxy compound, wherein the aromatic carbonic acid diester is obtained through the decarbonylation reaction of an aromatic oxalic acid diester represented by the following general formula (1): ???wherein two Ar's are the same or different aromatic hydrocarbon groups having 6 to 14 carbon atoms, and has a hydrolyzable halogen content of 5 ppm or less. According to the present invention, an aromatic polycarbonate having a high molecular weight and excellent color can be easily produced without impairing ester interchange reactivity for the production of the aromatic polycarbonate by using an aromatic carbonic acid diester obtained through the decarbonylation of an aromatic oxalic acid diester and controlling the amount of hydrolyzable halogen contained in the aromatic carbonic acid diester to a value smaller than a predetermined value.
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- Method of recovering and purifying diphenylcarbonate from phenolic solutions thereof
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Phenolic solutions of 20%-70% by weight of diphenylcarbonate have been found to form a crystalline 1:1 molar adduct of diphenylcarbonate and phenol when allowed to cool to a temperature between about 50° C. and 25° C. Recovery of the crystalline 1:1 molar adduct followed by distillation of phenol therefrom has been found to provide substantially pure diphenylcarbonate.
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- Process for the preparation of diarylcarbonates
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A process and a catalyst for the homogeneous liquid phase reaction of aromatic haloformates with aromatic hydroxy compounds for the production of diaryl carbonates with the elimination of anhydrous hydrogen halide. The organophosphine catalysts of the present invention permit the production of the products in very high yield, and the reaction proceeds at high rates.
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- gem-Difluorocyclopropenes by [1+2] cycloaddition reactions between difluorocarbene and acetylenes having terminal or internal triple bonds
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Difluorocarbene, generated by the Burton method, i.e. by the dissociation of (triphenylphosphonio)difluoromethanide, was found to add to terminal or internal acetylenes with astonishing ease. Actually, it reacts roughly 10 times faster with 4-octyne than with cis-4-octene. The gem-difluorocyclopropenes resulting from the [1+2] cycloaddition process can be isolated with good to excellent yields. They are perfectly stable under anhydrous conditions while in aqueous media they are quantitatively converted to cyclopropenones. - Unsubstituted olefinic ring positions rapidly undergo a base catalyzed hydrogen/deuterium exchange. The acidity of such 2-alkyl- or 2-aryl-1,1-difluorocyclopropenes is estimated to be higher than that of terminal acetylenes.
- Bessard, Yves,Schlosser, Manfred
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p. 7323 - 7328
(2007/10/02)
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- Cyclopropenone Oximes: Preparation and Reaction with Isocyanates
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2,3-Diphenyl-, 2-methyl-3-phenyl-, and 2-methyl-3-(4-methylphenyl)cyclopropenone oxime hydrochlorides (3) were prepared in good yields from the corresponding cyclopropenones and hydroxylamine hydrochloride in methanol.The salts 3 reacted with alkyl and aryl isocyanates in the presence of triethylamine to afford 1 : 2 addition products 4,6-diazaspirohexenones in moderate yields.In contrast, acetone, acetophenone, and cyclohexanone oximes reacted with twice excess of methyl isocyanates to give linear 1 : 1 addition products and benzophenone oxime yielded only 1 : 1 addition product.
- Yoshida, Hiroshi,Ohtsuka, Hideki,Yoshida, Keisuke,Totani, Yoshiyuki,Ogata, Tsuyoshi,Matsumoto, Kiyoshi
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p. 4347 - 4352
(2007/10/02)
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- Alkoxycarbenium Ions. Relative Thermodynamic Stabilities via Pairwise Equilibrations.
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Alkoxycarbenium ions were synthesized by direct O-alkylation of the corresponding carbonyl compounds with trimethyloxonium ion salts and methyl fluorosulfate.The thermodynamic stabilities of the alkoxycarbenium ions were determined by stepwise equilibrations of pairs of these ions via transalkylation with the corresponding carbonyl compounds in liquid sulfur dioxide as monitored by 1H NMR.The structures, spectra, and stabilities of alkoxycarbenium ions have been compared with those of the corresponding hydroxycarbenium ions.In general, the relative stability order for alkoxycarbenium ions parallels the order of stabilities for the corresponding hydroxycarbenium ions.
- Quirk, Roderic P.,Gambill, Charles R.,Thyvelikakath, George X.
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p. 3181 - 3186
(2007/10/02)
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