89-56-5Relevant academic research and scientific papers
Palladium-catalyzed ortho-C-H hydroxylation of benzoic acids
Luo, Feihua,He, Shuhua,Gou, Quan,Chen, Jinyang,Zhang, mingzhong
, (2021/10/06)
A simple Pd(OAc)2 catalyzed ortho-hydroxylation of benzoic acids using TBHP as the sole oxidant has been explored. This protocol features relatively broad substrate scope and operational simplicity. The compatibility of ortho-substituted substrates is an effective complement to the previous ortho-hydroxylation reaction.
Synthesis of cresotic acids by carboxylation of cresols with sodium ethyl carbonate
Suerbaev, Kh. A.,Chepaikin,Kudaibergenov, N. Zh.,Zhaksylykova, G. Zh.
, p. 646 - 650 (2016/08/16)
Carboxylation of o-cresol, m-cresol, and p-cresol with sodium ethyl carbonate (SEC) proceeds regioselectively with the formation of cresotic acids: 2-hydroxy-3-methylbenzoic acid, 2-hydroxy-4-methylbenzoic acid, and 2-hydroxy-5-methylbenzoic acid, respectively. Optimal conditions for conducting the process have been found to be as follows: the reactants ratio of [cresol]: [sodium ethyl carbonate] = (1.5–2): 1, T = 180–185°C, PCO2 = 10 atm, and t = 6–7 h. Simple and convenient methods for the synthesis of cresotic acids, which can be used for their industrial manufacturing, have been developed.
A versatile approach for the synthesis of para -substituted arenes via palladium-catalyzed C-H functionalization and protodecarboxylation of benzoic acids
Pan, Shulei,Zhou, Bo,Zhang, Yanghui,Shao, Changdong,Shi, Guangfa
supporting information, p. 277 - 281 (2016/01/20)
While a great number of ortho C-H functionalization reactions have been developed and several breakthroughs have been achieved in meta C-H activation, para C-H functionalization is still in its infancy stage. In this article, a versatile strategy for the synthesis of para-substituted arenes has been developed via a tandem process consisting of palladium-catalyzed C-H functionalization and subsequent copper-catalyzed protodecarboxylation of benzoic acids. Both electron-withdrawing and electron-donating functionalities can be introduced into the para positions of arenes bearing a variety of substituents.
Carboxylation of Phenols with CO2 at Atmospheric Pressure
Luo, Junfei,Preciado, Sara,Xie, Pan,Larrosa, Igor
supporting information, p. 6798 - 6802 (2016/05/11)
A convenient and efficient method for the ortho-carboxylation of phenols under atmospheric CO2 pressure has been developed. This method provides an alternative to the previously reported Kolbe-Schmitt method, which requires very high pressures of CO2. The addition of a trisubstituted phenol has proved essential for the successful carboxylation of phenols with CO2 at standard atmospheric pressure, allowing the efficient preparation of a broad variety of salicylic acids.
A concise synthetic route to the stereotetrad core of the briarane diterpenoids
Moon, Nicholas G.,Harned, Andrew M.
supporting information, p. 2218 - 2221 (2015/05/13)
A concise synthesis (under 10 steps) of the stereotetrad core of the briarane diterpenoids is reported. This approach harnesses the unique reactivity of salicylate ester derived 2,5-cyclohexadienones to quickly build complexity. In particular, a highly diastereoselective acetylide conjugate addition/β-ketoester alkylation sequence was used to set the relative configuration of the C1 (quaternary) and C10 (tertiary) vicinal stereocenters. The sterochemical outcome of the β-ketoester alkylation appears to be governed by torsional steering in the transition state.
A Baker-Venkataraman retro-Claisen cascade delivers a novel alkyl migration process for the synthesis of amides
Ameen, Dana,Snape, Timothy J.
supporting information, p. 1816 - 1819 (2015/03/30)
A simple extension of the carbamoyl Baker-Venkataraman rearrangement has been developed. If residual water in the reaction is not strictly excluded a Baker-Venkataraman retro-Claisen cascade takes place, giving amide products, in which an alkyl group apparently migrates between two functionalities of the substrate.
General method for the synthesis of salicylic acids from phenols through palladium-catalyzed silanol-directed C-H carboxylation
Wang, Yang,Gevorgyan, Vladimir
, p. 2255 - 2259 (2015/02/19)
A silanol-directed, palladium-catalyzed C-H carboxylation reaction of phenols to give salicylic acids has been developed. This method features high efficiency and selectivity, and excellent functional-group tolerance. The generality of this method was demonstrated by the carboxylation of estrone and by the synthesis of an unsymmetrically o,o′-disubstituted phenolic compound through two sequential C-H functionalization processes.
Regioselective ortho-carboxylation of phenols catalyzed by benzoic acid decarboxylases: A biocatalytic equivalent to the Kolbe-Schmitt reaction
Wuensch, Christiane,Gross, Johannes,Steinkellner, Georg,Lyskowski, Andrzej,Gruber, Karl,Glueck, Silvia M.,Faber, Kurt
, p. 9673 - 9679 (2014/03/21)
The enzyme catalyzed carboxylation of electron-rich phenol derivatives employing recombinant benzoic acid decarboxylases at the expense of bicarbonate as CO2 source is reported. In contrast to the classic Kolbe-Schmitt reaction, the biocatalytic equivalent proceeded in a highly regioselective fashion exclusively at the ortho-position of the phenolic directing group in up to 80% conversion. Several enzymes were identified, which displayed a remarkably broad substrate scope encompassing alkyl, alkoxy, halo and amino- functionalities. Based on the crystal structure and molecular docking simulations, a mechanistic proposal for 2,6-dihydroxybenzoic acid decarboxylase is presented.
Sulfoximines: A reusable directing group for chemo-and regioselective ortho C-H oxidation of arenes
Yadav, M. Ramu,Rit, Raja K.,Sahoo, Akhila K.
supporting information; experimental part, p. 5541 - 5545 (2012/06/01)
Sulfoximines direct: A new protocol for the chemo-and regioselective ortho C-H acetoxylation of arenes in N-benzoylated sulfoximines is reported. The sulfoximine directing group is easily detached from the C-H oxidation product through acid-promoted hydrolysis, isolated, and reused (see scheme). The meta-substituted phenols are synthesized following this strategy and the stereointegrity of the sulfoximine is preserved in this transformation. C(sp3)-H acetoxylation of the methyl group is also demonstrated.
Phenolic acid glucosides from the seeds of Entada phaseoloides Merill
Singh, Onkar,Ali, Mohd,Akhtar, Nida
body text, p. 682 - 687 (2011/09/21)
Phytochemical investigation of the defatted seeds of Entada phaseoloides Merill. (Mimosaceae) led to the isolation of three new phenolic acid glucosides, which were characterized as 2-hydroxy-5-methylbenzoyl-β-L-glucopyranoside (p-cresotyl glucoside, 1), 2-hydroxy-5-methylbenzoyl-β-L-glucopyranosyl (2 → 1)-β-L-glucopyranosyl (2 → 1)-β-L-glucopyranoside (p-cresotyl triglucoside, 2), and 2-hydroxybenzoyl-β-L-glucopyranosyl (2 → 1)-β-L-glucopyranosyl (2 → 1)-β-L-glucopyranosyl (2 → 1)-β-L-glucopyranoside (salicylic acid tetraglucoside, 5), along with sucrose and triglucoside. The structures of these phytoconstituents have been established on the basis of spectral data analysis and chemical reactions.
