18181-71-0

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.

We present here detailed mechanistic studies of electrocatalytic hydrogenation (ECH) in aqueous solution over skeletal nickel cathodes to probe the various paths of reductive catalytic C-O bond cleavage among functionalized aryl ethers relevant to energy science. Heterogeneous catalytic hydrogenolysis of aryl ethers is important both in hydrodeoxygenation of fossil fuels and in upgrading of lignin from biomass. The presence or absence of simple functionalities such as carbonyl, hydroxyl, methyl, or methoxyl groups is known to cause dramatic shifts in reactivity and cleavage selectivity between sp3 C-O and sp2 C-O bonds. Specifically, reported hydrogenolysis studies with Ni and other catalysts have hinted at different cleavage mechanisms for the C-O ether bonds in α-keto and α-hydroxy β-O-4 type aryl ether linkages of lignin. Our new rate, selectivity, and isotopic labeling results from ECH reactions confirm that these aryl ethers undergo C-O cleavage via distinct paths. For the simple 2-phenoxy-1-phenylethane or its alcohol congener, 2-phenoxy-1-phenylethanol, the benzylic site is activated via Ni C-H insertion, followed by beta elimination of the phenoxide leaving group. But in the case of the ketone, 2-phenoxyacetophenone, the polarized carbonyl πsystem apparently binds directly with the electron rich Ni cathode surface without breaking the aromaticity of the neighboring phenyl ring, leading to rapid cleavage. Substituent steric and electronic perturbations across a broad range of β-O-4 type ethers create a hierarchy of cleavage rates that supports these mechanistic ideas while offering guidance to allow rational design of the catalytic method. On the basis of the new insights, the usage of cosolvent acetone is shown to enable control of product selectivity.

We report a general protocol for the light-driven isomerization of cyclic aliphatic alcohols to linear carbonyl compounds. These reactions proceed via proton-coupled electron-transfer activation of alcohol O-H bonds followed by subsequent C-C β-scission of the resulting alkoxy radical intermediates. In many cases, these redox-neutral isomerizations proceed in opposition to a significant energetic gradient, yielding products that are less thermodynamically stable than the starting materials. A mechanism is presented to rationalize this out-of-equilibrium behavior that may serve as a model for the design of other contrathermodynamic transformations driven by excited-state redox events.

The invention relates to a method, for depolymerizing lignin into an aromatic compound by photocatalysis. Belong to application chemistry technical field. The method uses lignin as a reaction substrate, and under the excitation of a light source, under the catalysis of a light source, the C-C bond is selectively cracked under the assistance of a base and a hydrogen donor, and the molar ratio of the reaction substrate, photocatalyst, base, and hydrogen donor is 100: (0.5~10) 1~20: (1~20), and the reaction temperature is room temperature, and the reaction substrate is a reaction substrate. The reaction time was 6~24 hours. The method has the advantages, such as simple reaction steps, mild reaction conditions, high bond breaking selectivity 100%, high yield, atom efficiency, environmental protection and the like, has the functions, is high in selectivity, and efficiently degrades the lignin, and is beneficial to large-scale industrial production and application of lignin degradation and the like. (by machine translation)

Described is a tetrabutylammonium fluoride-mediated hydroxyalkylation reaction of phenols with cyclic carbonates. This operationally simple method enables the synthesis of a variety of aryl β-hydroxyethyl ethers in good to excellent yields with a very small amount of catalyst loading (0.1–1 mol%). Of particular note is the efficient conversion of aromatic diols and phloroglucinol to the corresponding bis- and tris-hydroxyethylated products. To further showcase the versatility of this protocol, guaifenesin was prepared with a single step by the condensation of guaiacol and glycerol carbonate. We also developed a flow ethoxylation process permitting the continuous synthesis of multiflorol. (Figure presented.).

The invention provides a preparation method for 2-(2-methoxyphenoxy)ethylamine. The preparation method comprises the following steps: synthesizing 2-(2-methoxyphenoxy)ethanol with guaiacol as a starting material; then synthesizing 2-(2-methoxyphenoxy)chloroethane through chlorination; then reacting 2-(2-methoxyphenoxy)chloroethane with potassium phthalimide to obtain N-(o-methoxyphenoxyethyl)-phthalimide; and finally, performing basic hydrolysis to obtain 2-(2-methoxyphenoxy)ethylamine. The yields of the above four steps of reactions are that the yield of 2-(2-methoxyphenoxy)ethanol is 98.9%;the yield of 2-(2-methoxyphenoxy)chloroethane is 93.7%; the yield of N-(o-methoxyphenoxyethyl)-phthalimide is 86.4%; the yield of 2-(2-methoxyphenoxy)ethylamine is 91.2%; and the total yield of the four steps is 73.04%, which is higher than the yield of 43% in conventional production processes. The preparation method of the invention reduces the production cost of 2-(2-methoxyphenoxy)ethylamine and is safe in the production process.

Lignin is a potentially abundant renewable resource for the production of aromatic chemicals, however its selective depolymerisation is challenging. Here, we report a new catalytic system for the depolymerisation of lignin to novel, non-phenolic monoaromatic products based on the selective β-O-4 primary alcohol dehydrogenation with a Cp?Ir-bipyridonate catalyst complex under basic conditions. We show that this system is capable of promoting the depolymerisation of model compounds and isolated lignins via a sequence of selective primary alcohol dehydrogenation, retro-aldol (Cα-Cβ) bond cleavage and in situ stabilisation of the aldehyde products by transfer (de)hydrogenation to alcohols and carboxylic acids. This method was found to give good to excellent yields of cleavage products with both etherified and free-phenolic lignin model compounds and could be applied to real lignin to generate a range of novel non-phenolic monomers including diols and di-acids. We additionally show, by using the same catalyst in a convergent, one-pot procedure, that these products can be selectively channelled towards a single di-acid product, giving much simpler product mixtures as a result.

Provided herein a vanadium(V) complex of formula I, where R1 to R8 are as defined herein. Also provided herein are reactions making use of the vanadium(V) complex of formula I, such as selective sp3-sp3 carbon-carbon bond cleavage under visible light photocatalysis and photodegradation of lignin.

Aiming to discover dual-acting β2 adrenergic/dopamine D2 receptor ligands, a structure-guided approach for the evolution of GPCR agonists that address multiple targets was elaborated. Starting from GPCR crystal structures, we describ

The invention relates to the field of pharmaceutical chemistry, and relates to formononetin derivatives and preparation methods and medical application thereof, in particular to formononetin derivatives with the general formula as shown in (I), preparation methods thereof, pharmaceutical compositions containing the compounds and medical application of the derivatives and the pharmaceutical compositions, particularly, application of the derivatives and the pharmaceutical compositions serving as drugs for preventing or treating hyperlipidaemia or obesity or type-II diabetes. Please see the formula in the description.

Ruthenium-triphos complexes exhibited unprecedented catalytic activity and selectivity in the redox-neutral C-C bond cleavage of the β-O-4 lignin linkage of 1,3-dilignol model compounds. A mechanistic pathway involving a dehydrogenation-initiated retro-aldol reaction for the C-C bond cleavage was proposed in line with experimental data and DFT calculations.

A facile synthesis of Carvedilol via a key 2-(2-methoxyphenoxy) ethyl 4-methylbenzenesulfonate intermediate is described and this approach avoids the formation of bis side product (impurity-B) due to weak basic conditions and also operationally suitable for industrial application.

Previously, we identified 1-(2-(4-bromophenoxy)ethoxy)-3-(4-(2- methoxyphenyl)piperazin-1-yl)propan-2-ol (1) as a novel Hsp90 inhibitor with moderate activity through virtual screening. In this study, we report the optimization process of 1. A series of analogues containing the 1-phenylpiperazine core scaffold were synthesized and evaluated. The structure-activity relationships (SAR) for these compounds was also discussed for further molecular design. This effort afforded the most active inhibitor 13f with improved activity in not only target-based level, but also cell-based level compared with the original hit 1.

A highly efficient copper-catalyzed C-O cross-coupling reaction between aryl bromides and aliphatic diols has been developed employing a cheaper, more efficient, and easily removable copper(ii) catalyst. A broad range of aryl bromides were coupled with aliphatic diols of different lengths using 5 mol% CuCl2 and 3 equivalents of K2CO3 in the absence of any other ligands or solvents to afford the corresponding hydroxyalkyl aryl ethers in good to excellent yields. In this newly developed protocol, aliphatic diols have multilateral functions as coupling reactants, ligands, and solvents. The resulting hydroxyalkyl aryl ethers were further readily converted into the corresponding phenols, presenting a valuable alternative way to phenols from aryl bromides. Furthermore, it was demonstrated that they are useful intermediates for more advanced molecules such as benzofurans and benzo-fused cyclic ethers. This journal is

Rhodococcus jostii RHA1, a polychlorinated biphenyl-degrading soil bacterium whose genome has been sequenced, shows lignin degrading activity in two recently developed spectrophotometric assays. Bioinformatic analysis reveals two unannotated peroxidase genes present in the genome of R. jostii RHA1 with sequence similarity to open reading frames in other lignin-degrading microbes. They are members of the Dyp peroxidase family and were annotated as DypA and DypB, on the basis of bioinformatic analysis. Assay of gene deletion mutants using a colorimetric lignin degradation assay reveals that a dypB mutant shows greatly reduced lignin degradation activity, consistent with a role in lignin breakdown. Recombinant DypB protein shows activity in the colorimetric assay and shows Michaelis-Menten kinetic behavior using Kraft lignin as a substrate. DypB is activated by Mn2+ by 5-23-fold using a range of assay substrates, and breakdown of wheat straw lignocellulose by recombinant DypB is observed over 24-48 h in the presence of 1 mM MnCl2. Incubation of recombinant DypB with a β-aryl ether lignin model compound shows time-dependent turnover, giving vanillin as a product, indicating that Cα- Cβ bond cleavage has taken place. This reaction is inhibited by addition of diaphorase, consistent with a radical mechanism for C-C bond cleavage. Stopped-flow kinetic analysis of the DypB-catalyzed reaction shows reaction between the intermediate compound I (397 nm) and either MnII (kobs = 2.35 s-1) or the β-aryl ether (k obs = 3.10 s-1), in the latter case also showing a transient at 417 nm, consistent with a compound II intermediate. These results indicate that DypB has a significant role in lignin degradation in R. jostii RHA1, is able to oxidize both polymeric lignin and a lignin model compound, and appears to have both MnII and lignin oxidation sites. This is the first detailed characterization of a recombinant bacterial lignin peroxidase.

The potential of cyclotriveratrylene (ctv) (2,3,7,8,12,13-hexamethoxy-10,15-dihydro-5H-tribenzocyclo-nonene) trithiols as ligands that can easily be functionalised and show subsite differentiation in their complexes with clusters has been explored.The cluster complexes of tris(2-sulfanylethoxy)- and tris(3-sulfanyl-methylbenzyloxy)-functionalised ctvs have been studied by core-extrusion experiments, spectroscopy and electrochemical techniques.With 2- as starting material a cluster complex was obtained in which the unique Fe and its co-ordinating Cl was turned into the cavity and show no reactivity.Starting with the more bulky t)4>2- the unique iron points outwards and is susceptible to substitution reactions.The effects of hydrogen bonding and electron density on the redox potential of the cluster complex have been investigated.The redox potential becomes more negative when the length of the spacer between the ctv and cluster core is increased, which is explained by the longer distance between the cluster and the electron-withdrawing phenoxy moiety of the ctv.The synthesis of ctv derivatives with one thiol and one alcohol functionality per phenyl unit, and comparison with corresponding derivatives where hydrogen bonding is not possible, showed that no significant differences were found.The effects of a substituent in an aromatic amide group that could hydrogen bond to the co-ordinated thiol were investigated.A weak effect, in the direction expected, was found upon substitution of methyl for H.

Sulfamate esters of the formula where A is aryloxyalkyl, p is the number of unreacted hydroxy groups present on the alkyl moiety and may be zero, z is the number of --OS(O)2 NR1 R2 groups attached to carbons of the alkyl moiety and is always at least one; R1 and R2 are selected from hydrogen, loweralkyl, carboxy, and the like are useful in treating glaucoma.

Methods of treating chronic arthritis and osteoporosis which utilize both known and novel compounds which would fall under the general formula:(HO)p--A--[--OS(O) 2 NR 1 R 2 ] zwherein A encompasses a wide range of values including but not limited to aryl, loweralkyl, cycloalkyl, and carbohydrates including sucrose and fructose; p is equal to the number of unreacted hydroxy groups contained on the molecule and may be zero; z is the number of --OS(O) 2 NR 1 R 2 groups and is always at least one; R 1 and R 2 are selected from hydrogen, loweralkyl, carboxy and the like; a novel process for preparing the compounds is provided wherein an appropriate sulfamic acid aryl ester is reacted with a hydroxy substituted A radical which may or may not contain thereon protected carboxyl, amino or hydroxy substituents, in an aprotic solvent containing a tertiary amine base. Pharmaceutical compositions for the treatment of chronic arthritis and osteoporosis are also provided.

The gas-phase Smiles reaction of RC6H4O(CH2)nO(1-) (n = 2 or 3) is an ipso rearrangement which is strongly influenced by the nature of the substituent R.Electron-withdrawing groups enhance the rearrangement.When the substituent R is halogen or Me, and occupies the ortho position, ortho cyclization competes with the Smiles rearrangement.