488-93-7Relevant articles and documents
GAS-PHASE PYROLYTIC REACTIONS. PART 4. ARRHENIUS PARAMETERS AND HAMMETT ρ CONSTANTS IN GAS-PHASE ELIMINATIONS OF ALKYL PYRIDYL-, FURYL-, AND THIENYLCARBOXYLATE ESTERS
Al-Awadi, Nouria A.,Al-Bashir, Rasha F.,ElDusouqui, Osman M. E.
, p. 2911 - 2916 (1990)
The first-order rate coefficients ( 105k/s-1) of the gas-phase pyrolytic reactions of seven isopropyl (hetero)arylcarboxylate esters were calculated for 600 K to be: 75.34 for benzoate, and 100.0, 70.46, 94.03, 65.58, 100.9 and 120.2 for 2-thienyl-, 3-thienyl-, 2-furyl-, 3-furyl-, 3-pyridyl- and 4-pyridylcarboxylate, respectively.The corresponding Hammett replacement ρ0 substituent constants of the heterocyclic groups are: 0.53, -0.13, 0.42, -0.26, 0.55 and 0.88, respectively.The reported ρ0 constants are in agreement with other gas-phase and solution data, and are amenable to rationalization in terms of normal electronic and structural effects.Further, the physical constants of four new isopropyl heteroarylcarboxylate esters are described.
A Simple Synthesis of 3-Tributylstannylfuran and 3-Lithiofuran
Fleming, Ian,Taddei, Maurizio
, p. 898 (1985)
3-Tributylstannylfuran is prepared in two steps from 2-butyne-1,4-diol.
Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
Sharifi, Sina,Sharifi, Hannah,Koza, Darrell,Aminkhani, Ali
, p. 803 - 808 (2021/07/20)
Disproportionation of aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions often requires the application of high temperatures, equimolar or excess quantities of strong bases, and is mostly limited to the aldehydes with no CH2 or CH3 adjacent to the carbonyl group. Herein, we developed an efficient, mild, and multifunctional catalytic system consisting AlCl3/Et3N in CH2Cl2, that can selectively convert a wide range of not only aliphatic, but also aromatic aldehydes to the corresponding alcohols, acids, and dimerized esters at room temperature, and in high yields, without formation of the side products that are generally observed. We have also shown that higher AlCl3 content favors the reaction towards Cannizzaro reaction, yet lower content favors Tishchenko reaction. Moreover, the presence of hydride donor alcohols in the reaction mixture completely directs the reaction towards the Meerwein–Ponndorf–Verley reaction. Graphic abstract: [Figure not available: see fulltext.].
Oxidation of Primary Alcohols and Aldehydes to Carboxylic Acids via Hydrogen Atom Transfer
Tan, Wen-Yun,Lu, Yi,Zhao, Jing-Feng,Chen, Wen,Zhang, Hongbin
supporting information, p. 6648 - 6653 (2021/09/08)
The oxidation of primary alcohols and aldehydes to the corresponding carboxylic acids is a fundamental reaction in organic synthesis. In this paper, we report a new chemoselective process for the oxidation of primary alcohols and aldehydes. This metal-free reaction features a new oxidant, an easy to handle procedure, high isolated yields, and good to excellent functional group tolerance even in the presence of vulnerable secondary alcohols and tert-butanesulfinamides.
Tert-Butyl Nitrite-Mediated Synthesis of N-Nitrosoamides, Carboxylic Acids, Benzocoumarins, and Isocoumarins from Amides
Yedage, Subhash L.,Bhanage, Bhalchandra M.
, p. 5769 - 5781 (2017/06/07)
This work reports tert-butyl nitrite (TBN) as a multitask reagent for (1) the controlled synthesis of N-nitrosoamide from N-alkyl amides, (2) hydrolysis of N-methoxyamides to carboxylic acids, (3) metal- and oxidant-free benzocoumarin synthesis from ortho-aryl-N-methoxyamides via N-H, C-N, and C-H bond activation, and (4) isocoumarin synthesis using Ru(II)/PEG as a recyclable catalytic system via ortho-C-H activation and TBN as an oxygen source. The sequential functional group interconversion of amide to acid has also been examined using IR spectroscopic analysis. Additionally, this methodology is highly advantageous due to short reaction time, gram scale synthesis, and broad substrate scope.
Carboxylation of organoboronic esters with potassium methyl carbonate under copper catalysis
Duong, Hung A.,Nguyen, Tuan Minh,Rosman, Nurul Zubaidah Binte,Tan, Lionel Jia Liang
, p. 1881 - 1885 (2014/07/22)
In the presence of a copper catalyst, potassium methyl carbonate serves as a versatile carboxylating agent of allyl- and arylboronic esters for the preparation of carboxylic acids. Georg Thieme Verlag Stuttgart New York.
Electrophilicity and nucleophilicity of commonly used aldehydes
Pratihar, Sanjay
, p. 5781 - 5788 (2014/07/22)
The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
Cooperative N-Heterocyclic Carbene (NHC) and Ruthenium Redox Catalysis: Oxidative Esterification of Aldehydes with Air as the Terminal Oxidant
Zhao, Junfeng,Mueck-Lichtenfeld, Christian,Studer, Armido
supporting information, p. 1098 - 1106 (2013/05/21)
The paper describes a cooperative NHC (N-heterocyclic carbene) and ruthenium-based redox catalysis for the mild aerobic oxidative esterification of various aromatic and heteroaromatic aldehydes. The ruthenium(II) complex Ru(bpz)3(PF6)2 (bpz=2,2′-bipyrazine) as catalyst is shown to be compatible with free NHCs. The NHC is used in these cascade reactions for the umpolung of the aldehyde to form the corresponding Breslow intermediate which in turn gets oxidized to an acylazolium ion by the ruthenium redox catalyst. Air is used as a terminal oxidant for oxidation (regeneration) of the ruthenium catalyst. In addition, we will show that in the absence of the ruthenium redox catalyst and alcohol, NHC-catalyzed aerobic oxidation of aldehydes delivers the corresponding acids in good to excellent yields. Mechanistic studies and DFT calculations supporting our suggested mechanisms are provided. Copyright
Domino rhodium/palladium-catalyzed dehydrogenation reactions of alcohols to acids by hydrogen transfer to inactivated alkenes
Trincado, Monica,Gruetzmacher, Hansjorg,Vizza, Francesco,Bianchini, Claudio
supporting information; experimental part, p. 2751 - 2757 (2010/06/17)
The combination of the d8 RhI diolefin amide [Rh(trop2N)(PPh3)] (trop2N=bis(5-H-dibenzo-[a, d]cyclohepten-5-yl)amide) and a palladium heterogeneous catalyst results in the formation of a superior catalyst system for the dehydrogenative coupling of alcohols. The overall process represents a mild and direct method for the synthesis of aromatic and heteroaromatic carboxylic acids for which inactivated olefins can be used as hydrogen acceptors. Allyl alcohols are also applicable to this coupling reaction and provide the corresponding saturated aliphatic carboxylic acids. This transformation has been found to be very efficient in the presence of silica-supported palladium nanoparticles. The dehydrogenation of benzyl alcohol by the rhodium amide, [Rh]N, follows the well established mechanism of metal-ligand bifunctional catalysis. The resulting amino hydride complex, [RhH]NH, transfers a H2 molecule to the Pd nanoparticles, which, in turn, deliver hydrogen to the inactivated alkene. Thus a domino catalytic reaction is developed which promotes the reaction R-CH 2-OH+NaOH+ 2 alkene→R-COONa+2 alkane.
Synthesis of novel furo-, thieno-, and pyrroloazepines
Villarreal, Carlos,Martinez, Roberto
experimental part, p. 3346 - 3352 (2010/11/17)
The synthesis of novel furo-, thieno-, and pyrroloazepine compounds, using the oxidative radical alkylation of three five-membered heterocyclic 3-acetic acid derivatives, is described. The bicyclic systems were obtained, via a small number of steps, directly from commercially available materials. Georg Thieme Verlag Stuttgart New York.