1835-04-7Relevant academic research and scientific papers
Friedel-Crafts propionylation of veratrole to 3,4-dimethoxypropiophenone over superacidic UDCaT-5 catalyst
Yadav, Ganapati D.,More, Santosh R.
, p. 123 - 130 (2012)
3,4-Dimethoxypropiophenone (3,4-DMPP) is of considerable commercial importance due to its use in fine chemical and drug industries. 3,4-DMPP is traditionally produced by the Friedel-Crafts propionylation of veratrole using homogeneous catalysts which are
Preparation method and application of apocynin and derivatives of apocynin
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Paragraph 0067-0070, (2020/01/12)
The invention belongs to the technical field of chemical biology, and particularly relates to a preparation method of apocynin and derivatives of the apocynin and an application of the apocynin and the derivatives of the apocynin in skin care products. The apocynin and the derivatives of the apocynin provided by the invention can promote collagen synthesis, help skin damage repair, and can be usedin the skin care products.
Cleavage of CC and Co bonds in β-O-4 linkage of lignin model compound by cyclopentadienone group 8 and 9 metal complexes
Kishino, Masamichi,Kusumoto, Shuhei,Nozaki, Kyoko
supporting information, p. 477 - 480 (2020/05/19)
Degradation of 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphe-noxy)propane-1,3-diol (1), a model compound for lignin β-O-4 linkage was examined with iron, ruthenium, rhodium and iridium complexes bearing cyclopentadienone ligand. Cyclopentadienone iron complex gave only a small amount of degraded product with reduced molecular weight. Cyclopentadienone ruthenium complex, so called Shvo's catalyst, afforded 3,4-dimethoxybenzaldehyde (a3) in 14.3% yield after CαCβ bond cleavage. On the other hand, cyclopentadienone group-9 metal complexes catalyzed CβO bond cleavage to afford guaiacol (b1) as a main product in up to 74.9% yield.
Rhodium-terpyridine catalyzed redox-neutral depolymerization of lignin in water
Liu, Yuxuan,Li, Changzhi,Miao, Wang,Tang, Weijun,Xue, Dong,Xiao, Jianliang,Zhang, Tao,Wang, Chao
supporting information, p. 33 - 38 (2020/01/13)
Simple rhodium terpyridine complexes were found to be suitable catalysts for the redox neutral cleavage of lignin in water. Apart from cleaving lignin model compounds into ketones and phenols, the catalytic system could also be applied to depolymerize dioxasolv lignin and lignocellulose, affording aromatic ketones as the major monomer products. The (hemi)cellulose components in the lignocellulose sample remain almost intact during lignin depolymerization, providing an example of a "lignin-first" process under mild conditions. Mechanistic studies suggest that the reaction proceeds via a rhodium catalyzed hydrogen autotransfer process.
Cobalt-Catalyzed Migrational Isomerization of Styrenes
Zhao, Jiajin,Cheng, Biao,Chen, Chenhui,Lu, Zhan
supporting information, p. 837 - 841 (2020/01/31)
An efficient cobalt-catalyzed migrational isomerization of styrenes was developed using the thiazoline iminopyridine (TIP) ligand. This reaction is operationally simple and atom-economical using readily available starting materials to access trisubstituted alkenes. Even when using a 0.1 mol % catalyst loading, the reaction could be conducted in neat and completed in 1 h with excellent conversion and high E stereoselectivity.
Mild Redox-Neutral Depolymerization of Lignin with a Binuclear Rh Complex in Water
Liu, Yuxuan,Li, Changzhi,Miao, Wang,Tang, Weijun,Xue, Dong,Li, Chaoqun,Zhang, Bo,Xiao, Jianliang,Wang, Aiqin,Zhang, Tao,Wang, Chao
, p. 4441 - 4447 (2019/05/14)
A mild redox-neutral lignin depolymerization system featuring a water-soluble binuclear Rh complex has been developed. The catalytic system could be successfully applied to the depolymerization of a lignin-like polymer, alkaline lignin, as well as raw lignocellulose samples to produce aromatic ketones, providing a homogeneous catalytic system for "lignin-first" biorefinery in water. Mechanistic studies on the model substrate suggest that the reaction proceeds via a metal-catalyzed dehydrogenation step to afford a carbonyl intermediate, followed by C-O bond cleavage to afford ketone and phenol products. Deuterium labeling study shows that the hydrogen used for cleavage of the C-O bond originates from the alcohol moiety in the substrate.
A convenient synthetic approach to dioncoquinone B and related compounds
Khmelevskaya, Ekaterina A.,Pelageev, Dmitry N.
supporting information, p. 1022 - 1024 (2019/03/13)
A total synthesis of dioncoquinone B and related compounds, including ancistroquinones B, C and malvon A, is presented. The strategy is based on available reagents and can be used as a preparative synthesis of a number of natural and synthetic biologically active (3-alkyl)-2,7,8-di(tri)methoxy(hydroxy)-1,4-naphthoquinones.
METHOD FOR THE DEACYLATION AND/OR DEALKYLATION OF COMPOUNDS
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, (2019/02/15)
The present invention in general relates to a method for the deacylation and/or dealkylation (both O-dealkylation as well as C-dealkylation) of compounds, more specifically of aromatic compounds. The method is characterized by contacting the compound with an acid-containing aqueous reaction mixture using high temperature and high pressure conditions. The invention also provides a method for preparing a compound suitable for further deacylation using the method of the invention.
Visible-Light-Driven Self-Hydrogen Transfer Hydrogenolysis of Lignin Models and Extracts into Phenolic Products
Luo, Nengchao,Wang, Min,Li, Hongji,Zhang, Jian,Hou, Tingting,Chen, Haijun,Zhang, Xiaochen,Lu, Jianmin,Wang, Feng
, p. 4571 - 4580 (2017/07/24)
Obtaining high selectivity of aromatic monomers from renewable lignin has been extensively pursued but is still unsuccessful, hampered by the need to efficiently cleave C-O/C-C bonds and inhibit lignin proliferation reactions. Herein, we report a transfer hydrogenolysis protocol using a heterogeneous ZnIn2S4 catalyst driven by visible light. In this process, alcoholic groups (CαH-OH) of lignin act as hydrogen donors. Proliferation of phenolic products to dark substances is suppressed under visible light illumination at low temperature (below 50 °C); formation of a light and transparent reaction solution allows visible light to be absorbed by the catalyst. With this strategy, 71-91% yields of phenols in the conversion of lignin β-O-4 models and a 10% yield of p-hydroxyl acetophenone derivatives from organosolv lignin are achieved. Mechanistic studies reveal that CαH-OH groups of lignin β-O-4 linkage are initially dehydrogenated on ZnIn2S4 to form a "hydrogen pool", and the adjacent Cβ-O bond is subsequently hydrogenolytically cleaved to two monomers by the "hydrogen pool". Thus, the dehydrogenation and hydrogenolysis reaction are integrated in one-pot with lignin itself as a hydrogen donor. This study shows a promising way of supplying phenolic compounds by taking advantages of both renewable biomass feedstocks and photoenergy.
Method for degrading lignin
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Paragraph 0048; 0049; 0050, (2017/10/28)
The invention discloses a method for degrading lignin. Water is used as a solvent. The method includes carrying out reaction on the lignin under the effects of double-rhodium catalysts or terpyridine rhodium trichloride catalysts and alkali under the protection of inert gas at the temperatures of 100-120 DEG C for 10-16 hours to degrade the lignin. Compared with existing methods, the method has the advantages that extra hydrogen sources can be omitted, the water is used as the solvent, reaction conditions are mild, the method is easy to implement, high in reaction yield and low in industrial production cost and is green and environmentally friendly, and environmental pollution can be abated.
