100-09-4Relevant articles and documents
Facile electrochemical transformation of diazonium salts into carboxylic acids
Otero, M. Dolores,Batanero, Belen,Barba, Fructuoso
, p. 8215 - 8216 (2006)
The electrolyses of aryldiazonium tetrafluoroborates in dry DMF and Bu4NHSO4 as solvent-supporting electrolyte system, in the presence of CO2 led to the corresponding arylcarboxylic acids in very good yields.
A simple, one-pot oxidative esterification of aryl aldehydes through dialkyl acetal using hydrogen peroxide
Devarajan,Vijayakumar,Ramalingam,Vijayaraghavan
, p. 5849 - 5858 (2016)
A simple and an efficient one-pot procedure has been developed to synthesize various aryl carboxylic esters directly from aryl aldehydes using hydrogen peroxide without any catalyst. The reaction proceeds smoothly at room temperature. A preliminary investigation suggests the formation of dialkyl acetal as an intermediate during the reaction sequence.
Diphenyl disulfide and sodium in NMP as an efficient protocol for in situ generation of thiophenolate anion: Selective deprotection of aryl alkyl ethers and alkyl/aryl esters under nonhydrolytic conditions
Chakraborti, Asit K.,Nayak, Mrinal K.,Sharma, Lalima
, p. 1776 - 1780 (2002)
Aryl methyl ethers, methyl esters, aryl esters, and aryl sulfonates are chemoselectively deprotected under nonhydrolytic conditions by treatment with Ph2S2 (0.6 equiv) and Na (1.6 equiv) in NMP under reflux or at 90°C. Quantitative utilization of the 'PhS' moiety as the effective nucleophilic species represents conservation of atom economy. Other solvents such as HMPA, DMPU, DMEU, and DMF afforded comparable results. Chloro, nitro, aldehyde, α,α-diketone, and α,β-unsaturated ketone functionalities remain unaffected. The deprotection was found to take place in the order aryl ester > alkyl ester > aryl alkyl ether. Substrates bearing strong electron-withdrawing groups react at a faster rate than those not having such substitution. The differences in rate of reaction has been exploited for selective deprotection for intramolecular competition. An aryl acetate/benzoate is deprotected selectively in preference to a methyl ester or aryl methyl ether. Selective deprotection of a methyl ester is observed in the presence of an aryl alkyl ether.
Bromate exchange resin as an oxidizing agent in organic synthesis
Chetri, Ajay B.,Kalita, Biswajit,Das, Pranab J.
, p. 3317 - 3319 (2000)
Bromate exchange resin has been prepared by a simple elution technique and used for the oxidation of aromatic aldehydes to the carboxylic acids. Oxidation is carded out under biphasic condition. Work up is simple. Resin immobilized bromate ions have been used for the first time as an oxidizing agent in organic synthesis.
Homogeneous catalytic oxidation of styrene and styrene derivatives with hydrogen peroxide in the presence of transition metal-substituted polyoxotungstates
Duarte, Tiago A. G.,Estrada, Ana C.,Simes, Mrio M. Q.,Santos, Isabel C. M. S.,Cavaleiro, Ana M. V.,Neves, M. Graca P. M. S.,Cavaleiro, Jos A. S.
, p. 351 - 363 (2015)
The tetrabutylammonium (TBA) salts of the Keggin-type polyoxotungstates with general formula [XW11M(H2O)O39](n-m)-, where X = P, B or Si and M = Mn, Fe or Co, were evaluated as catalysts in the oxidation of styrene, α-methylstyrene, p-methylstyrene, α,p-dimethylstyrene, p-chlorostyrene, p-nitrostyrene, and p-methoxystyrene under mild conditions, using aqueous H2O2 as an eco-sustainable oxidant. In this study, the influence of the catalysts and of the different styrene substituents on the oxidation reaction profile was evaluated in terms of conversion and selectivity. For all the performed catalytic studies, the main product results from the oxidative cleavage of the vinyl double bond, except in the case of the oxidation of p-methoxystyrene catalysed by BW11Mn, for which p-methoxyphenol is the main product. The catalysts BW11Mn and SiW11Co give rise to 100% conversion for almost all of the substrates, excluding p-methoxystyrene and p-nitrostyrene for both catalysts and α,p-dimethylstyrene only in the case of BW11Mn. The selectivity for C=C cleavage products resulting from the oxidative cleavage of the vinyl double bond can be as high as 98%, reaching 98% conversion for p-nitrostyrene when SiW11Co was used as a catalyst. Possible pathways are discussed and the oxidation of a few presumed intermediates was carried out. The systematic study of several substituted styrene derivatives suggests a possible reactivity order for these compounds in the catalytic system considered.
Mechanism of Solvolysis of Substituted Benzoyl Halides
Song, Byeong Doo,Jencks, William P.
, p. 8470 - 8479 (1989)
Most substituted benzoyl fluorides undergo hydrolysis in aqueous solution through an associative mechanism with ρ = 1.7, kHOH/kDOD = 2.3+/-0.2, little dependence on the leaving group (kCl/kF = 1.2), and general-base catalysis by fluoride ion.There is an abrupt change to a dissociative mechanism through an acylium ion intermediate for the hydrolysis of p-(dimethylamino)benzoyl and (in part) p-anisoyl fluorides, with ρ+ =/Cl/kF = 10E6-10E7, and kHOH/kDOD = 1.1 for p-Me2NPhCOF.Common ion inhibition by fluoride ion traps the p-(dimethylamino)benzoyl acylium ion, which undergoes hydration with kh ca. 10E9-10E10 s-1.The increase in the solvent isotope effect for hydrolysis of p-(dimethylamino)benzoyl fluoride to kHOH/kDOD = 1.9 in the presence of concentrated potassium fluoride is attributed to general-base-catalyzed hydration of the acylium ion intermediate.The large yield of trifluoroethyl ester from the solvolysis of p-anisoyl fluoride in TFE/EtOH/HOH suggests that the acylium ion reacts in a solvent-separated ion pair, with kh ca. 10E12 s-1; extrapolation predicts rate constants of =/> 10E13 s-1 for the hydration of less stable acylium ions.A change in sensitivity to solvent ionizing power from m = 1.4 in water to m = 0 in 60percent ethanol for p-(dimethylamino)benzoyl fluoride suggests a change to an associative mechanism.Benzoyl fluorides and acylium ions show selectivity toward alcohols, with βnuc ca. 0.2.The absence of common ion inhibition for the solvolysis of several benzoyl chlorides in water or 90percent TFE/HOH is consistent with kh >10E11 s-1 for the acylium ions.Solvolysis occurs through the dissociative reaction channel, with ρ+ = -3.0, even when the estimated lifetimes of the acylium ion species suggest that there is no chemical barrier for their hydration.However, there is a change to an associative mechanism for the solvolysis of p-nitrobenzoyl chloride in water.
Green and simple synthesis of p-anisic acid and other analogs from methyl paraben
Periyasamy, Senthil,Subbiah, Selvaraj
, p. 85 - 88 (2018)
Synthesis of p-anisic acid from commercially available methyl paraben was obtained in good yield and performed the each steps in shorter duration is reported. The E-factor was evaluated for each step was 3.0 and 2.30 respectively without transition metals content in the waste disposal. The solvents used in each steps were completely recovered and recycled in the consecutive batches. This methodology was applied to the synthesis of p-ethoxy benzoic acid and p-propyloxy benzoic acid and the other derivatives from methyl paraben obtained in good yield.
Alumina-mediated microwave thermolysis: A new approach to deprotection of benzyl esters
Varma, Rajender S.,Chatterjee, Arnab K.,Varma, Manju
, p. 4603 - 4606 (1993)
A simple and high yielding method for deprotection of benzyl esters is described which occurs under mild and solvent-free conditions on alumina surface using microwave irradiation.
Dithioester-enabled chemodivergent synthesis of acids, amides and isothiazoles via C[sbnd]C bond cleavage and C[sbnd]O/C[sbnd]N/C[sbnd]S bond formations under metal- and catalyst-free conditions
Soni, Sonam,Koley, Suvajit,Singh, Maya Shankar
, p. 2512 - 2516 (2017)
An operationally simple and user-friendly process to access privileged scaffolds such as acids, amides and isothiazoles has been devised employing β-ketodithioesters for the first time. Remarkably, the new protocol involves combination of C[sbnd]C bond cl
A Novel Fragmentation Reaction of α-(N-Siloxy)anilino Ketones induced by Fluoride Ions
Ohno, Masatomi,Ido, Motohisa,Eguchi, Shoji
, p. 1530 - 1531 (1988)
The reaction of α-(N-siloxy)anilino-substituted aromatic ketones with tetrabutylammonium fluoride afforded aromatic acids and aniline as the fragmentation products, presumably via ring rupture of the intermediate 1,2-oxazetidine.
