- Iron-catalyzed arene C-H hydroxylation
-
The sustainable, undirected, and selective catalytic hydroxylation of arenes remains an ongoing research challenge because of the relative inertness of aryl carbon-hydrogen bonds, the higher reactivity of the phenolic products leading to over-oxidized by-products, and the frequently insufficient regioselectivity. We report that iron coordinated by a bioinspired L-cystine-derived ligand can catalyze undirected arene carbon-hydrogen hydroxylation with hydrogen peroxide as the terminal oxidant. The reaction is distinguished by its broad substrate scope, excellent selectivity, and good yields, and it showcases compatibility with oxidation-sensitive functional groups, such as alcohols, polyphenols, aldehydes, and even a boronic acid. This method is well suited for the synthesis of polyphenols through multiple carbon-hydrogen hydroxylations, as well as the late-stage functionalization of natural products and drug molecules.
- Cheng, Lu,Wang, Huihui,Cai, Hengrui,Zhang, Jie,Gong, Xu,Han, Wei
-
-
- Method for promoting iron-catalyzed oxidation of aromatic compound carbon - hydrogen bond to synthesize phenol by ligand
-
The method comprises the following steps: iron is used as - a catalyst metal; a sulfur-containing amino acid or cystine-derived dipeptide is a ligand; and under the common action of hydrogen peroxide as an oxidizing agent, an aromatic compound is synthesized to prepare a phenol. Under the action of an acid as an accelerant and hydrogen peroxide as an oxidizing agent, the aryl carbon - hydrogen bond is directly hydroxylated to form a phenolic compound, and the method for preparing the phenol by the catalytic oxidation reaction has a plurality of advantages. The reaction raw materials, the oxidant and the promoter are wide in source, low in price, environment-friendly and good in stability. The aromatic compound carbon - hydrogen bonds directly participate in the reaction to react in one step to form phenol. The reaction condition is mild, the functional group compatibility and the application range are wide. The reaction selectivity is good; under the optimized reaction conditions, the target product separation yield can reach 85%.
- -
-
Paragraph 0102-0103; 0129
(2021/09/21)
-
- Synthesis method of drug intermediate 4-bromo-2,3-dihydroxybenzaldehyde
-
The invention provides a synthetic method of a drug intermediate 4-bromo-2,3-dihydroxybenzaldehyde. According to the method disclosed by the invention, catechol is used as a raw material, and the 4-bromo-2,3-dihydroxybenzaldehyde medical intermediate is successfully synthesized through formylation reaction and bromination reaction under the action of an inorganic base and a phase transfer catalyst. The method has the advantages of high yield, few side reactions, high purity, short synthesis steps, conventional and easily available starting materials, low cost and environmental friendliness, and has a good industrial application prospect.
- -
-
Paragraph 0024-0031
(2021/02/20)
-
- Structural features and antioxidant activities of Chinese quince (Chaenomeles sinensis) fruits lignin during auto-catalyzed ethanol organosolv pretreatment
-
Chinese quince fruits (Chaenomeles sinensis) have an abundance of lignins with antioxidant activities. To facilitate the utilization of Chinese quince fruits, lignin was isolated from it by auto-catalyzed ethanol organosolv pretreatment. The effects of three processing conditions (temperature, time, and ethanol concentration) on yield, structural features and antioxidant activities of the auto-catalyzed ethanol organosolv lignin samples were assessed individually. Results showed the pretreatment temperature was the most significant factor; it affected the molecular weight, S/G ratio, number of β-O-4′ linkages, thermal stability, and antioxidant activities of lignin samples. According to the GPC analyses, the molecular weight of lignin samples had a negative correlation with pretreatment temperature. 2D-HSQC NMR and Py-GC/MS results revealed that the S/G ratios of lignin samples increased with temperature, while total phenolic hydroxyl content of lignin samples decreased. The structural characterization clearly indicated that the various pretreatment conditions affected the structures of organosolv lignin, which further resulted in differences in the antioxidant activities of the lignin samples. These results can be helpful for controlling and optimizing delignification during auto-catalyzed ethanol organosolv pretreatment, and they provide theoretical support for the potential applications of Chinese quince fruits lignin as a natural antioxidant in the food industry.
- Cheng, Xi-Chuang,Guo, Xin-Ran,Liu, Hua-Min,Liu, Yu-Lan,Qin, Zhao,Wang, Xue-De
-
p. 4348 - 4358
(2020/09/22)
-
- Cleavage of Catechol Monoalkyl Ethers by Aluminum Triiodide-Dimethyl Sulfoxide
-
Using eugenol and vanillin as model substrates, a practical method is developed for the cleavage o -hydroxyphenyl alkyl ethers. Aluminum oxide iodide (O=AlI), generated in situ from aluminum triiodide and dimethyl sulfoxide, is the reactive ether cleaving species. The method is applicable to catechol monoalkyl ethers as well as normal phenyl alkyl ethers for the removal of methyl, ethyl, isopropyl, and benzyl groups. A variety of functional groups such as alkenyl, allyl, amide, cyano, formyl, keto, nitro, and halogen are well tolerated under the optimum conditions. Partial hydrodebromination was observed during the demethylation of 4-bromoguaiacol, and was resolved using excess DMSO as an acid scavenger. This convenient and efficient procedure would be a practical tool for the preparation of catechols.
- Sang, Dayong,Tian, Juan,Tu, Xiaodong,He, Zhoujun,Yao, Ming
-
p. 704 - 712
(2019/01/23)
-
- Method for fully synthesizing berberine
-
The invention discloses a method for fully synthesizing berberine, and relates to a drug synthesis method. The method realizes the industrial full synthesis production of the berberine and is made from a bulk organic raw material catechol, the raw material is easily available, and the price is low; 2,3-dimethoxybenzaldehyde is obtained through selective formylation and methylation of the catechol;after a piperonyl ring is obtained through a catechol methylenenation reaction, piperonyl amine is synthesized through a one-step catalytic addition reaction, so that the synthesis steps of the piperonyl amine are shortened, the use of toxic cyanide is avoided, and the process is green and sustainable; condensation hydrogenation and salification reactions adopt a 'one-pot method', and thus the time and the energy are saved, and the cost is decreased. Industrialized full synthesis production of the berberine opens up large-scale production of the berberine, meets the clinical and research needs of the berberine in current anti-tumor, anti-blood pressure, anti-heart rhythm, blood sugar reduction, treatment of Alzheimer's disease and the like, provides effective drugs for reducing pain of patients, and has remarkable economic and social benefits.
- -
-
Paragraph 0013; 0017
(2019/04/17)
-
- Method for preparing 2,3-dihydroxybenzaldehyde by removing methyl of o-vanillin
-
The invention discloses a method for preparing 2,3-dihydroxybenzaldehyde by removing methyl of o-vanillin. The method comprises the following steps: in an organic solvent, in the presence of aluminumtrichloride and an iodide, the o-vanillin is subjected to an ether bond cleavage reaction at temperature of -20 DEG C to reflux temperature to form the 2,3-dihydroxybenzaldehyde. The method disclosedby the invention has mild conditions, is simple to operate and has a high yield.
- -
-
Paragraph 0021; 0022; 0025; 0026
(2018/11/26)
-
- A new method for preparing intermediates of Fludioxonil (by machine translation)
-
The invention relates to the field of organic synthesis, in particular to a new method for preparing intermediates of Fludioxonil. Difluoro [...] formaldehyde intermediate the synthesis method of the cyclization, chlorinated, fluorine exchange, hydrolysis and the like steps to synthesize. The process is complicated, the unit step more, harsh requirements on equipment, and the yield is low, to the detriment of the industrial production. The invention relates to O-vanillin as the starting material, the preparation of 2, 3 - dihydroxy benzaldehyde, with difluorodichloromethane reaction, in the presence of a, cyclization to obtain important [...] formaldehyde intermediate, not only the process is greatly improved, and the yield is high, waste water is less, there are better application value. (by machine translation)
- -
-
Paragraph 0023-0025
(2018/07/07)
-
- Novel use of amine compounds
-
The invention provides a preparation method and novel use of amine compounds. Specifically, the invention provides compounds shown in the formula A or their optical isomers, racemes, solvates or pharmaceutically acceptable salts and a medical use thereof. The above compounds can be used for preparation of a pharmaceutical composition or a preparation. The pharmaceutical composition or preparationis used for (a) inhibiting a transient receptor potential channel protein TRPA1 and (b) treating diseases associated with the transient receptor potential channel protein, wherein each group is defined in the specification.
- -
-
Paragraph 0179; 0180; 0181; 0182
(2018/06/28)
-
- Ether bond cracking method of phenylalkyl ether
-
The invention discloses an ether bond cracking method of phenylalkyl ether. The method comprises the following steps: performing ether bond breaking reaction on phenylalkyl ether at -20 to reflux temperature in the presence of aluminium triiodide and dimethyl sulfoxide, thereby generating phenol and derivatives thereof. The method disclosed by the invention is mild in condition, simple and convenient for operation, high in yield, and extensive in applicable phenylalkyl ether range.
- -
-
Paragraph 0150-0152
(2018/11/26)
-
- Formation of Phenolic Compounds from d -Galacturonic Acid
-
Aqueous d-galacturonic acid (d-GalA) model systems treated at 130 °C at different pH values show an intense color formation, whereas other reducing sugars, such as d-galactose (d-Gal), scarcely react. GC-MS measurements revealed the presence of several ph
- Urbisch, Alexandra,Einhorn-Stoll, Ulrike,Kastner, Hanna,Drusch, Stephan,Kroh, Lothar W.
-
-
- Efficient microwave-assisted regioselective one pot direct: Ortho -formylation of phenol derivatives in the presence of nanocrystalline MgO as a solid base catalyst under solvent-free conditions
-
In this research, at first nanocrystalline MgO was prepared and then the solvent-free reactions of phenol derivatives with paraformaldehyde in the presence of the obtained nanocrystalline MgO as a new catalyst under microwave irradiation were investigated. In this reaction, ortho-hydroxyaromatic aldehydes were yielded as products. This method seems to be comparable with other reported methods due to its high yield and regioselectivity. The significant features of this method are short reaction times, high yields, and easy and quick isolation of the products.
- Naeimi, Hossein,Zakerzadeh, Elham
-
p. 4590 - 4595
(2018/03/21)
-
- Synthetic method of 2,2-dichloro-1,3-benzodioxole-4-formaldehyde
-
The invention provides a synthetic method of 2,2-dichloro-1,3-benzodioxole-4-formaldehyde. The synthetic method comprises the following steps of: adding 3-methoxyl-2-hydroxybenzaldehyde and alkali into a protonic solvent, then dropwise adding hydrogen peroxide, and performing hydrolysis reaction; after the complete reaction, performing the after-treatment to obtain 2,3-dihydroxy benzaldehyde; adding an aqueous solution of the 2,3-dihydroxy benzaldehyde and alkali into the protonic solvent, and then adding dichlorodifluoromethane to perform the reaction; and after the complete reaction, performing the after-treatment to obtain the 2,2-dichloro-1,3-benzodioxole-4-formaldehyde. According to the synthetic method, the target product can be obtained from an initial raw material 3-methoxyl-2-hydroxybenzaldehyde by virtue of two-step chemical reaction. The reaction method is moderate in reaction conditions, simple in steps, low in cost, environment-friendly, high in yield, capable of facilitating the industrialized mass production, and capable of setting a foundation for the subsequent successful synthesis of fludioxonil, so that the synthetic method has good application prospect and market potential.
- -
-
Paragraph 0050-0052
(2017/07/14)
-
- Carbodiimides as Acid Scavengers in Aluminum Triiodide Induced Cleavage of Alkyl Aryl Ethers
-
A practical procedure for the cleavage of alkyl aryl ethers containing labile functional groups has been developed using aluminum triiodide as the ether cleaving reagent. Carbodiimides, typically used as dehydration reagents for the coupling of amines and carboxylic acids to yield amide bonds, are found to be effective hydrogen iodide scavengers that prevent acid-labile groups from deterioration. The method is applicable to variant alkyl aryl ethers such as eugenol, vanillin, ortho -vanillin and methyl eugenol. Suitable substrates are not limited to alkyl o -hydroxyphenyl ethers.
- Sang, Dayong,Wang, Jiahui,Zheng, Yun,He, Jianyuan,Yuan, Caili,An, Qing,Tian, Juan
-
p. 2721 - 2726
(2017/06/13)
-
- Ether bond breakage method for phenylalkyl ethers
-
The invention discloses an ether bond breakage method for phenylalkyl ethers. The method comprises the step: subjecting the phenylalkyl ethers to an ether bond breakage reaction at the temperature of -20 DEG C to reflux temperature in an organic solvent in the presence of aluminum triiodide and carbodiimide, so as to produce phenols and derivatives thereof. The method is moderate in conditions, simple and convenient in operation, high in yield and wide in applicable phenylalkyl ether range.
- -
-
Paragraph 0172; 0173
(2017/07/19)
-
- A phenyl alkyl ether ether linkage breaking method (by machine translation)
-
The invention discloses a phenyl alkyl ether ether linkage breaking method, the method is: in the organic solvent, in the presence of a mineral acid and the aluminium triiodide scavenging agent under the conditions of, phenyl ether in the - 20 °C to reflux temperature lower ether linkage breaking reaction, generating phenol and its derivatives. The mild conditions, the operation is simple, and the yield is high, the applicable phenyl ether range is wide. (by machine translation)
- -
-
Paragraph 0100-0102
(2018/04/01)
-
- Efficient symmetrical bidentate dioxime ligand-accelerated homogeneous palladium-catalyzed Suzuki-Miyaura coupling reactions of aryl chlorides
-
A series of N,O-bidentate ligands were synthesized using the Vilsmeier-Haack reaction and oximation. 2,5-Dihydroxyterephthalaldehyde dioxime (L8) as an efficient N,O-symmetrical bidentate ligand was prepared from hydroquinone. It was studied as a high activity ligand for palladium-catalyzed Suzuki-Miyaura cross-coupling reactions of aryl chlorides with arylboronic acids under mild conditions. The coupling reactions were performed in the presence of PdCl2 as the catalyst, L8 as the ligand, Na2CO3 as the base, PEG-400 as the PTC and in ethanol/water (1?:?1) as an environmentally benign solvent at 85 °C. Plentiful biaryls were obtained by the optimized reaction with good yields at a low palladium loading of 0.20 mol%.
- Song, Jinyi,Zhao, Hongyan,Liu, Yang,Han, Huatao,Li, Zhuofei,Chu, Wenyi,Sun, Zhizhong
-
supporting information
p. 372 - 376
(2016/12/30)
-
- Microwave-assisted Vilsmeier-Haack formylation of aromatic substrates
-
A microwave-assisted Vilsmeier-Haack formylation reaction has been studied on various amines, phenols and polynuclear hydrocarbons under solvent free condition that rapidly affords higher yield of products compared to traditional thermal condition.
- Ghosh, Kumaresh,Adhikari, Suman
-
experimental part
p. 959 - 961
(2009/12/24)
-
- Mechanophore-linked addition polymers
-
The use of mechanical energy to increase reaction rates and alter the distribution of products has gained considerable interest of late. However, the discovery of new mechanophores (i.e., mechanochemically reactive units) is currently time-consuming, expensive, low-yielding, and a process that is not easily scaled to large quantities. Here we show that mechanophore-linked addition polymers are easily prepared using bifunctional initiators with a living radical polymerization method. The mechanophore is positioned close to the center of the polymer, where ultrasound-generated forces are the largest. Since these forces are strongly dependent on molecular weight, the use of controlled polymerization enables fine-tuning of the mechanical activity so that mechanophore reactions are initiated while minimizing chain scission. The approach is illustrated first with the synthesis and investigation of a 1,2-disubstituted benzocyclobutene mechanophore that is incorporated into the center of a polymethacrylate (PMA) chain. Selected molecular weights are probed using ultrasound to illustrate that the 4π electrocyclic ring opening of the benzocyclobutene link is stress-induced. To demonstrate the broad applicability of this method for mechanophore screening, we also report a new spiropyran-linked PMA that undergoes an ultrasound-induced 6π-electron electrocyclic ring opening. The straightforward synthesis of mechanophore-linked addition polymers presented here shows considerable promise for the investigation of new mechanophores and will lead to a greater understanding of mechanochemical reactivity within polymer systems. Copyright
- Potisek, Stephanie L.,Davis, Douglas A.,Sottos, Nancy R.,White, Scott R.,Moore, Jeffrey S.
-
p. 13808 - 13809
(2008/04/04)
-
- Bocdene and mocdene derivatives of catechols and catecholamines.
-
[reaction in text] Catechols react chemoselectively, in the presence of either alcohols, 1,2-diols, or simple phenols, with tert-butyl propynoate and with methyl propynoate to give 2-Boc-ethylidene (Bocdene) and 2-Moc-ethylidene (Mocdene) acetals, respectively, in 96-100% yields within 30 min at room temperature, provided that 150 mol % of DMAP is added. Cleavage of these acetals with pyrrolidine readily takes place (at room temperature!) in 95-100% yields. By taking advantage of the features of Bocdene acetals, novel catecholamine-related phosphate mimetics have been prepared.
- Ariza,Pineda,Vilarrasa,Shipps Jr.,Ma,Dai
-
p. 1399 - 1401
(2007/10/03)
-
- Flash vacuum pyrolysis of methoxy-substituted lignin model compounds
-
The flash vacuum pyrolysis (FVP) of methoxy-substituted fi-O-4 lignin model compounds has been studied at 500 °C to provide mechanistic insight into the primary reaction pathways that occur under conditions of fast pyrolysis. FVP of PhCH2CH2OPh (PPE), a model of the dominant β-O-4 linkage in lignin, proceeds by C-O and C-C cleavage, in a 37:1 ratio, to produce styrene plus phenol as the dominant products and minor amounts of toluene, bibenzyl, and benzaldehyde. From the deuterium isotope effect in the FVP of PhCD2CH2OPh, it was shown that C-O cleavage occurs by homolysis and by 1,2- elimination in a ratio of 1.4:1, respectively. Methoxy substituents enhance the homolysis of the β-O-4 linkage, relative to PPE, in o-CH3O- C6H4OCH2CH2Ph (o-CH3O-PPE) and (o-CH3O)2-C6H3OCH2CH2Ph ((o- CH3O)2-PPE) by a factor of 7.4 and 21, respectively. The methoxy- substituted phenoxy radicals undergo a complex series of reactions, which are dominated by 1,5-, 1,6-, and 1,4-intramolecular hydrogen abstraction, rearrangement, and α-scission reactions. In the FVP of o-CH3O-PPE, the dominant product, salicylaldehyde, forms from the methoxyphenoxy radical by a 1,5-hydrogen shift to form 2-hydroxyphenoxymethyl radical, 1,2-phenyl shift, and β-scission of a hydrogen atom. The 2-hydroxyphenoxymethyl radical can also cleave to form formaldehyde and phenol in which the ratio of 1,2-phenyl shift to β-scission is ca. 4:1. In the FVP of o-CH3O-PPE and (o-CH3O)2- PPE, products (ca. 20 mol %) are also formed by C-O homolysis of the methoxy group. The resulting phenoxy radicals undergo 1,5- and 1,6-hydrogen shifts in a ratio of ca. 2:1 to the aliphatic or benzylic carbon, respectively, of the phenethyl chain. In the FVP of (o-CH3O)2-PPE, o-cresol was the dominant product. It was formed by decomposition of 2-hydroxy-3- hydroxymethylbenzaldehyde and 2-hydroxybenzyl alcohol, which are formed from a complex series of reactions from the 2,6-dimethoxyphenoxy radical. The key step in this reaction sequence was the rapid 1,5-hydrogen shift from 2- hydroxy-3-methoxybenzyloxy radical to 2-hydroxymethyl-6-methoxyphenoxy radical before β-scission of a hydrogen atom to give the substituted benzaldehyde. The 2-hydroxybenzyl alcohols rapidly decompose under the reaction conditions to o-benzoquinone methide and pick up hydrogen from the reactor walls to form o-cresol.
- Britt, Phillip F.,Buchanan III,Cooney, Mark J.,Martineau, Dan R.
-
p. 1376 - 1389
(2007/10/03)
-
- Reimer-Tiemann reactions of guaiacol and catechol in the presence of β-cyclodextrin
-
Fairly high selectivities with respect to para-product are achieved when guaiacol and catechol are subjected to Reimer-Tiemann reaction in the presence of β-cyclodextrin (BCD).Although the presence of BCD does not enhance the total aldehyde production, it reduces the proportion of other isomeric aldehydes formed in favour of the para-product.Thus the reaction in the presence of BCD yields 32percent more vanillin in the case of guaiacol and 25percent more protocatechuic aldehyde in the case of catechol in comparison to the one in the absence of BCD.
- Divakar, S.,Maheswaran, M. M.,Narayan, M. S.
-
p. 543 - 546
(2007/10/02)
-
- Derivatives of 1,3-Benzdioxoles, 48. Preparation and Reactions of 1,3-Benzdioxole-4,7-quinones
-
We describe the preparation of a substituted 1,3-benzdioxole-4,7-quinone complex (2) by reaction of 4-hydroxy-1,3-benzdioxole (1) with potassiumnitrosodisulfonate.The quinones 4a-d can be obtained by treatment of the 4-hydroxy-7-methoxy-1,3-benzdioxoles 3a-d with ammoniumcerium(IV)nitrate.Reaction of 2 with several cyclophiles gives the addition compounds resp. the dehydrogenation-products 6b-d in partly high yields. - Keywords: 1,3-Benzdioxol-4,7-chinon, 6,7-Dimethyl-naphtho-1,3-dioxol-4,9-chinon, 6-Hydroxy-naphtho-1,3-dioxol-4,9-chinon
- Dallacker, Franz,Holtmann, Bodo,Coerver, Wim
-
p. 392 - 397
(2007/10/02)
-
- 3-ETHOXY-2-HYDROXYBENZALDEHYDE AS A STARTING COMPOUND FOR SYNTHESIS OF ISOQUINOLINE ALKALOIDS
-
3-Ethoxy-2-hydroxybenzaldehyde (I) was used to prepare 6-bromo-2,3-dihydroxybenzaldehyde (V), 6-bromo-2,3-methylenedioxybenzaldehyde (VIa), 6-bromo-2,3-methylenedioxybenzoic acid (VIIa), and for new synthesis of compounds II, IIIa, IIIb, IV, VIb, VIIb, VIIIa, VIIIb, IXa and IXb.
- Smidrkal, Jan
-
p. 2140 - 2144
(2007/10/02)
-
- ORTHO-HYDROXYLATION SELECTIVE DES PHENOLS : II - UN NOUVEAU SYSTEME CATALYTIQUE A CARACTERE PREPARATIF.
-
A direct synthetic transformation of phenols into copper(II) catecholates (i.e. catechols) is described, which involves a copper-catalyzed activation of molecular oxygen.The mechanism and scope of this new reaction are discussed.
- Capdevielle, Patrice,Maumy, Michel
-
p. 1577 - 1580
(2007/10/02)
-
