877-22-5Relevant academic research and scientific papers
PROCESS FOR PRODUCTION OF CARBOXYLATED PHENOL DERIVATIVES
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Page/Page column 11-13, (2019/02/25)
Disclosed is a new process for the production of carboxylated phenol derivatives comprising at least a step of carboxylation of a mixture of (i) phenol derivative and (ii) phenolate derivative, wherein the molar ratio of (i) / (ii) is comprised between 0.8 and 1.2, in presence of CO2. A process for the production of said mixture of (i) phenol derivative and (ii) phenolate derivative is also disclosed.
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.
Pd/C and NaBH4 in basic aqueous alcohol: An efficient system for an environmentally benign oxidation of alcohols
An, Gwangil,Ahn, Hyunseok,De Castro, Kathlia A.,Rhee, Hakjune
experimental part, p. 477 - 485 (2010/06/13)
We report the oxidation of a wide range of alcohols using an environmentally benign and economical process. The use of Pd/C heterogeneous catalysts along with NaBH4in aqueous ethanol or methanol and either K2CO3 or KOH as base at room temperature under molecular oxygen or air give the corresponding oxidation products. This protocol is versatile since it is capable of oxidizing alcohols to its desired carbonyl or carboxyl counterpart. Room temperature reaction in aqueous system and recyclability of the catalyst are among the advantages of this manipulation. These advantages make the process safe and cheaper rendering it favorable from both economic and environmental viewpoints. Georg Thieme Verlag Stuttgart New York.
Iron-promoted ortho-And/or ipso-hydroxylation of benzoic acids with H 2O2
Makhlynets, Olga V.,Das, Parthapratim,Taktak, Sonia,Flook, Margaret,Mas-Balleste, Ruben,Rybak-Akimova, Elena V.,Que Jr., Lawrence
experimental part, p. 13171 - 13180 (2010/07/03)
Regioselective hydroxylation of aromatic acids with hydrogen peroxide proceeds readily in the presence of iron(II) complexes with tetradentate aminopyridine ligands [FeII(BPMEN)-(CH3CN) 2](ClO4)2 (1) and [FeII(TPA)- (CH3CN)2](OTf)2 (2), where BPMEN=N, N'-dimethyl-N, N'-bis(2-pyridylmethyl)-1,2-ethylenediamine, TPA=tris-(2- pyridylmethyl)amine. Two cis-sites, which are occupied by labile acetonitrile molecules in 1 and 2, are available for coordination of H2O 2 and substituted benzoic acids. The hydroxylation of the aromatic ring occurs exclusively in the vicinity of the anchoring carboxylate functional group: ortho-hydroxylation affords salicylates, whereas ipso-hydroxylation with concomitant decarboxylation yields phenolates. The outcome of the substituent directed hydroxylation depends on the electronic properties and the position of substituents in the molecules of substrates:3-substituted benzoic acids are preferentially ortho-hydroxylated, whereas 2-and, to a lesser extent, 4-substituted substrates tend to undergo ipso-hydroxylation/decarboxylation. These two pathways are not mutually exclusive and likely proceed via a common intermediate. Electron-withdrawing substituents on the aromatic ring of the carboxylic acids disfavor hydroxylation, indicating an electrophilic nature for the active oxidant. Complexes 1 and 2 exhibit similar reactivity patterns, but 1 generates a more powerful oxidant than 2. Spectroscopic and labeling studies exclude acylperoxoiron(III) and FeIV=O species as potential reaction intermediates, but strongly indicate the involvement of an FeIII-OOH intermediate that undergoes intramolecular acid-promoted heterolytic O-O bond cleavage, producing a transient iron(V) oxidant.
First general, direct, and regioselective synthesis of substituted methoxybenzoic acids by ortho metalation
Nguyen, Thi-Huu,Chau, Nguyet Trang Thanh,Castanet, Anne-Sophie,Nguyen, Kim Phi Phung,Mortier, Jacques
, p. 3419 - 3429 (2008/02/03)
(Chemical Equation Presented) New general methodology of value in aromatic chemistry based on ortho-metalation sites in o-, m-, and p-anisic acids (1-3) (Scheme 1) is described. The metalation can be selectively directed to either of the ortho positions by varying the base, metalation temperature, and exposure times. Metalation of o-anisic acid (1) with s-BuLi/TMEDA in THF at -78°C occurs exclusively in the position adjacente to the carboxylate. On the other hand, a reversal of regioselectivity is observed with n-BuLi/t-BuOK. With LTMP at 0°C, the two directors of m-anisic acid (2) function in concert to direct introduction of the metal between them while n-BuLi/t-BuOK removes preferentially the proton located ortho to the methoxy and para to the carboxylate (H-4). s-BuLi/TMEDA reacts with p-anisic acid (3) exclusively in the vicinity of the carboxylate. According to these methodologies, routes to very simple methoxybenzoic acids with a variety of functionalities that are not easily accessible by other means have been developed (Table 1).
Environmentally benign oxidation reaction of aldehydes to their corresponding carboxylic acids using Pd/C with NaBH4 and KOH
Lim, Minkyung,Yoon, Cheol Min,An, Gwangil,Rhee, Hakjune
, p. 3835 - 3839 (2008/02/07)
Pd/C catalyst in aqueous methanol with sodium borohydride and potassium hydroxide under the air efficiently oxidized aldehydes to their corresponding carboxylic acids at room temperature. The utilization of room temperature reaction, aqueous methanol solvent, and the open-air conditions make this manipulation very interesting for economic and environmental perspectives.
Method for oxidising an aromatic aldehyde into the corresponding carboxylic acid
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Page 7, (2008/06/13)
The present invention concerns a process for oxidising an aromatic aldehyde to the corresponding carboxylic acid. The process of the invention for preparing an aromatic acid by oxidising an aromatic aldehyde consists of carrying out the oxidation of the aromatic aldehyde in a basic medium using molecular oxygen or a gas containing molecular oxygen in the presence of a catalyst, and is characterized in that oxidation is carried out in the presence of an effective quantity of a palladium and/or platinum based catalyst under conditions such that oxidation is carried out in a diffusion regime.
Demethoxylation and hydroxylation of methoxy- and hydroxybenzoic acids by OH-radicals. Processes of potential importance for food irradiation
Gaisberger,Solar
, p. 394 - 404 (2007/10/03)
The hydroxylation process for methoxy- and hydroxy-benzoic acids (MBA, HBA) induced by γ-radiation is compared. 2-, 3-, and 4-methoxybenzoic acid as well as 3-hydroxybenzoic acid have been irradiated in N2O and aerated solutions up to 1.5 kGy. The products were analyzed by HPLC. The results for 2- and 4-HBA have been taken from literature data. The OH·-adduct distribution is generally the same for the hydroxy- as well as for the methoxy-benzoic acid isomers. With both 4-HBA and 4-MBA more than 65% C3-adducts and about 15% C4-adducts are formed, which could be proved by their reactions with K3 Fe(CN)6. Oxidation of the nonipso-adducts of 3-HBA and 3-MBA results in 84 and 87% of the corresponding phenols. Whereas in N2O-saturated solutions only part of the OH·-radicals leads to substrate decomposition, in the presence of air, the degradation of both kinds of compounds is equivalent to [OH·]. The nonipso OH·-adducts of the HBAs are converted into 68-77% hydroxylation products. With the MBAs, the hydroxylation process is ≤10%. This is attributed to different decay pathways of the peroxyl radicals, intermediates formed by O2 addition to the OH·-adducts. The hydroxyperoxycyclohexadienyl radicals of the HBAs decay mainly by HO2· elimination to the corresponding phenols, those of the MBAs decay predominantly by fragmentation of the benzene ring, yielding to nonidentified aliphatic products. The replacement of -OCH3 by -OH is practically not influenced by the presence of oxygen, it increases in the sequence 3-MBA 4-MBA 2-MBA. For 2-MBA, yields of more than 15% are obtained. Both processes, hydroxylation as well as demethoxylation, might be of importance for the recognition of radiolytical changes in foodstuff.
Regioselective dealkylation of 2-alkoxybenzoic acid and its amide derivatives with aliphatic amines
Nishioka, Hiroyasu,Nagasawa, Masaaki,Yoshida, Kiyoshi
, p. 243 - 246 (2007/10/03)
The methoxy group of o-anisic acid was cleaved with aliphatic amines in aprotic dipolar solvents. This cleavage reaction was especially smooth when piperazine in dimethylacetamide was used. This method was applicable to a variety of dealkylations of o-alkoxybenzoic acid and ist amide derivatives with high regio-selectivity.
External preparation for skin
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, (2008/06/13)
An external preparing for skin comprising one or more than two types of 2-hydroxy benzoic acid derivative and/or salt thereof represented by the following formula: STR1 wherein R is an alkoxy group or alkyl group in the formula. The external preparation for the skin according to the present invention has a suppression effect on melanine generation by inhibition of tyrosinase activity. Accordingly, an excellent bleaching effect based upon the suppression of chromatosis and a high degree of safety can be obtained.
