- Me3SI-promoted chemoselective deacetylation: a general and mild protocol
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A Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developedviaemploying KMnO4as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.
- Gurawa, Aakanksha,Kashyap, Sudhir,Kumar, Manoj
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p. 19310 - 19315
(2021/06/03)
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- Controlled lignosulfonate depolymerization: Via solvothermal fragmentation coupled with catalytic hydrogenolysis/hydrogenation in a continuous flow reactor
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Sodium lignosulfonate (LS) was valorized to low molecular weight (Mw) fractions by combining solvothermal (SF) and catalytic hydrogenolysis/hydrogenation fragmentation (SHF) in a continuous flow system. This was achieved in either alcohol/H2O (EtOH/H2O or MeOH/H2O) or H2O as a solvent and Ni on nitrogen-doped carbon as a catalyst. The tunability according to the temperature of both SF and catalytic SHF of LS has been separately investigated at 150 °C, 200 °C, and 250 °C. In SF, the minimal Mw was 2994 g mol-1 at 250 °C with a dispersity (?) of 5.3 using MeOH/H2O. In catalytic SHF using MeOH/H2O, extremely low Mw was found (433 mg gLS-1) with a ? of 1.2 combined with 34 mg gLS-1. The monomer yield was improved to 42 mg gLS-1 using dual catalytic beds. These results provide direct evidence that lignin is an unstable polymer at elevated temperatures and could be efficiently deconstructed under hydrothermal conditions with and without a catalyst. This journal is
- Al-Naji, Majd,Antonietti, Markus,Brandi, Francesco
-
supporting information
p. 9894 - 9905
(2021/12/24)
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- Nickel-catalyzed reductive deoxygenation of diverse C-O bond-bearing functional groups
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We report a catalytic method for the direct deoxygenation of various C-O bond-containing functional groups. Using a Ni(II) pre-catalyst and silane reducing agent, alcohols, epoxides, and ethers are reduced to the corresponding alkane. Unsaturated species including aldehydes and ketones are also deoxygenated via initial formation of an intermediate silylated alcohol. The reaction is chemoselective for C(sp3)-O bonds, leaving amines, anilines, aryl ethers, alkenes, and nitrogen-containing heterocycles untouched. Applications toward catalytic deuteration, benzyl ether deprotection, and the valorization of biomass-derived feedstocks demonstrate some of the practical aspects of this methodology.
- Cook, Adam,MacLean, Haydn,St. Onge, Piers,Newman, Stephen G.
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p. 13337 - 13347
(2021/11/20)
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- 3'-KETOGLYCOSIDE COMPOUND FOR THE SLOW RELEASE OF A VOLATILE ALCOHOL
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The present invention relates to a 3'-ketoglycoside compound defined by formula (I) and its use for controlled release of alcohols, in particular alcohols showing an insect repellent effect. It relates also to a process for preparing the 3'-ketoglycoside compound of formula (I). It further relates to a composition comprising a 3'- ketoglycoside compound of formula (I). It relates also to the use of a 3'-ketoglycoside compound of formula (I) for the controlled release of alcohols. It related also to a method of use of such composition.
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- Molybdate Stabilized Magnesium‐Iron Hydrotalcite Materials: Potential Catalysts for Isoeugenol to Vanillin and Olefin Epoxidation
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A series of molybdate-intercalated and stabilized magnesium‐iron hydrotalcite (HMFeMo) materials with different molybdate loadings were successfully prepared by an in-situ hydrothermal method. The prepared HMFeMo materials were systematically characterized using Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), Ultraviolet-visible spectroscopy, scanning electron microscopy, thermo-gravimetric analysis, nitrogen adsorption-desorption and X-ray photoelectron spectroscopy (XPS) experiments. The XRD results demonstrated the successful intercalation of molybdate ions in the interlayer space of magnesium-iron hydrotalcite and the stabilization of the layered structure. In addition, the XPS spectra of the HMFeMo materials revealed the presence of molybdenum in a higher-valent oxidation state. The calcination of HMFeMo materials led to the formation of solid solution of mixed metal oxides. Both the as-prepared and calcined HMFeMo catalysts showed promising activity for the epoxidation of cyclooctene, as a model reaction. Furthermore, the performance of the as-prepared and calcined HMFeMo catalysts for the oxidation of a biomass model compound, namely isoeugenol to vanillin, was evaluated. The isoeugenol conversion over the as-prepared HMFeMo catalysts under solvent-free conditions and using tertiary-butyl hydroperoxide in decane as the oxidant was good. Moreover, the isoeugenol conversion and selectivity toward vanillin of HMFeMo0.1, with a molybdate loading of 0.1 mol %, were the highest (86.2% and 83.1%, respectively) of all HMFeMo catalysts in this study at 80 °C for 5 hr. HMFeMo0.1 presented the best catalytic activity for both the epoxidation of cyclooctene and oxidation of isoeugenol to vanillin, and its activity remained unchanged after several runs.
- Neethu, P. P.,Sakthivel, A.,Sreenavya, A.
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- Continuous flow study of isoeugenol to vanillin: A bio-based iron oxide catalyst
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The use of a biorefinery co-product, such as humins, in combination with an iron precursor in a solvent-free method yields a catalytic material with potential use in selective oxidative cleavage reactions. In particular, this catalyst was found active in the hydrogen-peroxide assisted oxidation of a naturally extracted molecule, isoeugenol, to high added-value flavouring agent, vanillin. By carrying out the reaction in continuous flow, not only a better understanding of the reaction mechanism and of the catalyst deactivation can be achieved, but also important insights for optimised conditions can be developed. The findings of this paper could pave the way to a more sustainable process for the production of a valuable food and perfume additive, vanillin.
- Filiciotto, Layla,Márquez-Medina, María Dolores,Pineda, Antonio,Balu, Alina M.,Romero, Antonio A.,Angelici, Carlo,de Jong, Ed,van der Waal, Jan C.,Luque, Rafael
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p. 281 - 290
(2019/12/25)
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- Synthesis and First-Time Assessment of o-Eugenol Derivatives against Mycobacterium tuberculosis
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In this work, we report the first-time assessment of o-eugenol, 6-allyl-2-methoxyphenol, and their selected derivatives, against Mycobacterium tuberculosis H37RV, using the MABA susceptibility test. The bromo, nitro, O-alkylated, and reduced derivatives were obtained by standard methods and were characterized by spectroscopic and mass spectral data. Structure–activity relationships were investigated, with the most active derivatives being 4,5-dibromo-2-methoxy-6-propylphenol (139 μM) and 2-methoxy-3-nitro-6-propylphenol (237 μM). This study provides important information on the rational design of new lead anti-TB drugs based on o-eugenol derivatives.
- Moraes, Adriana Marques,da Silva, Emerson Teixeira,Wardell, James L.,de Souza, Marcus V. N.
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p. 633 - 638
(2020/07/30)
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- Synthetic method of eugenol
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A synthetic method of eugenol comprises the following steps of: dropwise adding a halogenating reagent into guaiacol, adding an alkaline saturated solution for layering, washing with water, drying, filtering, and carrying out reduced pressure distillation to obtain 4-halogen-2-methoxyphenol; adding 4-halogen-2-methoxyphenol and alkali into an organic solvent, adding alkyl halide alkyl ether, adding water, layering, extracting the water layer with a solvent, drying the organic layer, filtering, and removing the solvent to obtain 4-halogen-2-methoxy-1-alkoxy alkylphenol; dropwise adding 4-halogen-2-methoxy-1-alkoxy alkylphenol into an ether solution of allyl magnesium halide; adding an ammonium chloride aqueous solution to obtain a mixture, carrying out reduced pressure distillation to remove ether, carrying out water layer extraction, combining ethyl acetate layers, drying, filtering, and carrying out reduced pressure distillation to obtain 4-allyl-2-methoxy-1-alkoxy alkylphenol; and mixing the product with p-toluenesulfonic acid monohydrate, stirring, carrying out reduced pressure distillation, and carrying out high vacuum distillation to obtain eugenol. The defects that in the prior art, guaiacol directly reacts with 3-chloropropene, so that ortho-position reaction is easier, and the para-position product yield is low and does not exceed 50% are overcome.
- -
-
-
- Method for synthesizing eugenol
-
A method for synthesizing eugenol comprises the steps that firstly, guaiacol, lithium chloride and a catalytic amount of copper chloride are dissolved in glacial acetic acid, bubbling is conducted, oxygen is introduced for a reaction, and 4-chloro-2-methoxyphenol is obtained; then, 4-chloro-2-methoxyphenol reacts with alkyl halide alkyl ether in the presence of alkali to obtain 4-chloro-2-methoxy-1-alkoxy alkylphenol; 4-chloro-2-methoxy-1-alkoxy alkylphenol reacts with allyl magnesium halide in an ether solution to obtain 4-allyl-2-methoxy-1-alkoxy alkylphenol; and finally, 4-allyl-2-methoxy-1-alkoxy alkylphenol and p-toluenesulfonic acid monohydrate react in an organic solvent, and after the organic solvent is removed, residues obtained are subjected to high vacuum distillation to obtainthe eugenol product. According to the method, the problems that in the prior art, guaiacol directly reacts with 3-chloropropene to easily generate ortho-isomers difficult to separate, and the yield ofthe para-product eugenol is low are successfully solved, the quality of the eugenol product is improved, and the yield of eugenol is increased to 70% or above.
- -
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- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
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A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
-
supporting information
p. 16702 - 16707
(2020/10/27)
-
- Structural features and antioxidant activities of Chinese quince (Chaenomeles sinensis) fruits lignin during auto-catalyzed ethanol organosolv pretreatment
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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
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p. 4348 - 4358
(2020/09/22)
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- Photoactivatable Odorants for Chemosensory Research
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The chemosensory system of any animal relies on a vast array of detectors tuned to distinct chemical cues. Odorant receptors and the ion channels of the TRP family are all uniquely expressed in olfactory tissues in a species-specific manner. Great effort has been made to characterize the molecular and pharmacological properties of these proteins. Nevertheless, most of the natural ligands are highly hydrophobic molecules that are not amenable to controlled delivery. We sought to develop photoreleasable, biologically inactive odorants that could be delivered to the target receptor or ion channel and effectively activated by a short light pulse. Chemically distinct ligands eugenol, benzaldehyde, 2-phenethylamine, ethanethiol, butane-1-thiol, and 2,2-dimethylethane-1-thiol were modified by covalently attaching the photoremovable protecting group (8-cyano-7-hydroxyquinolin-2-yl)methyl (CyHQ). The CyHQ derivatives were shown to release the active odorant upon illumination with 365 and 405 nm light. We characterized their bioactivity by measuring activation of recombinant TRPV1 and TRPA1 ion channels expressed in HEK 293 cells and the electroolfactogram (EOG) response from intact mouse olfactory epithelium (OE). Illumination with 405 nm light was sufficient to robustly activate TRP channels within milliseconds of the light pulse. Photoactivation of channels was superior to activation by conventional bath application of the ligands. Photolysis of the CyHQ-protected odorants efficiently activated an EOG response in a dose-dependent manner with kinetics similar to that evoked by the vaporized odorant amyl acetate (AAc). We conclude that CyHQ-based, photoreleasable odorants can be successfully implemented in chemosensory research.
- Gore, Sangram,Ukhanov, Kirill,Herbivo, Cyril,Asad, Naeem,Bobkov, Yuriy V.,Martens, Jeffrey R.,Dore, Timothy M.
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p. 2516 - 2528
(2020/10/02)
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- METHOD OF FORMING MONOMERS AND FURFURAL FROM LIGNOCELLULOSE
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The present disclosure relates to a method of producing monophenolicmonomers and furfural from lignocellulosic biomass beating the biomass in a solvent together with a zeolite based catalyst.
- -
-
Page/Page column 19; 21; 22
(2020/06/05)
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- CATALYTIC CONVERSION OF BIOMASS TO BIOPHENOL
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The invention relates to a demethoxylation process for demethoxylating alkylmethoxyphenols using an aromatic solvent to produce alkylphenols. The invention also relates to dealkylation process for dealkylating alkylphenols using an aromatic solvent to produce phenol. The invention further relates to a tandem demethoxylation and dealkylation process, which can be performed in a single reactor. The process is useful in the conversion of lignin derived alkylmethoxyphenols into biophenol.
- -
-
Page/Page column 19; 21-22
(2019/10/04)
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- Ferrocene derivatives of liquid chiral molecules allow assignment of absolute configuration by X-ray crystallography
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The present study investigates a synthetically simple ferrocene derivatization of natural products and active pharmaceutical ingredients. Seven new crystal structures are analyzed together with 16 structures of ferrocene derivatives reported previously. In all cases, the unambiguous determination of the absolute structure was established from anomalous dispersion using the methods of Flack and Parsons. A comparison with other derivatization approaches shows the advantage of the described ferrocene derivatization for establishing the absolute configuration of novel compounds.
- Holstein, Philipp M.,Holstein, Julian J.,Escudero-Adán, Eduardo C.,Baudoin, Olivier,Echavarren, Antonio M.
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p. 1321 - 1329
(2017/10/17)
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- Benign-by-design preparation of humin-based iron oxide catalytic nanocomposites
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The current acid-catalyzed conversion of biomass feedstocks yields substantial quantities of undesired by-products called humins, for which applications are yet to be found. This work aims to provide a starting point for valorisation of humins via preparation of humin-based iron oxide catalytic nanocomposites from humins and thermally treated humins (foams) via solvent-free methodologies including ball milling and thermal degradation. The prepared materials were found to be active in the microwave-assisted selective oxidation of isoeugenol (conversions >87%) to vanillin, proving the feasibility to use humin by-products as template/composite materials.
- Filiciotto, Layla,Balu, Alina M.,Romero, Antonio A.,Rodríguez-Castellón, Enrique,Van Der Waal, Jan C.,Luque, Rafael
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p. 4423 - 4434
(2017/09/27)
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- N,N-dimethylation of nitro-eugenol to its new 4-allyl-2-(dimethylamino)-6-methoxyphenol via Eschweiler-Clarke methylation reaction
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Eugenol is a main constituent of essential oil and can be extracted and isolated from clove (Syzygium aromaticum). Eugenol has widely biological activities such as antiseptic and anesthetic. Eugenol can be used as a fine chemical for further synthesis of new or novel compounds. The main aim of this research was to develop new or novel compounds with potential biological activity such as 4-allyl-2-(dimethylamino)-6-methoxyphenol from eugenol (1). Derivatization of eugenol to its nitro derivative (2) can be achieved by treated with ammonium nitrate and potassium bisulphate. One-pot synthesis method via the Eschweiler-Clarke methylation of nitroeugenol using formaldehyde, formic acid, Zn catalyst, gave the N,N-dimethylation of nitro moiety. The result was then analyzed by GC-MS and NMR. The GC-MS analyses showed peak with m/z of 207 (59.51 %) and consistent with the molecular formula C12H17O2N. The 1 H NMR was in accordance with the proposed structure which showed 17 protons corresponded to 4-allyl-2-(dimethylamino)-6-methoxyphenol (3).
- Sudarma,Satriani,Darmayanti
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p. 867 - 869
(2017/02/10)
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- A rapid, solvent-free deprotection of methoxymethyl (MOM) ethers by pTSA; An eco-friendly approach
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Background: Ease of preparation and alkaline stability of methoxymethyl (MOM) makes it an important hydroxyl protecting group. A number of methods are available for the deprotection of MOM. Though the methods are good in general, they use solvents, require prolonged reaction time and tedious work up. A solvent free, solid phase, fast deprotection of MOM has been developed and is the major theme of this paper. Methods: A mixture of MOM protected compounds and pTSA is triturated in a mortar (5 min) and left at room temperature for 30 min. On addition of water (4°C), pTSA, methanol and formaldehyde dissolved leaving the products as precipitates. Results: A series of different MOM ethers were deprotected by this method in good to excellent yield (85-98%). The compatibility of MOM in the presence of other protections such as methoxyl, benzyl, ester, amide, allyl and lactone was also established. Acetate protection is not stable under these conditions. Conclusion: An efficient, selective and high yielding deprotection MOM groups by pTSA under solvent free condition is described. The process is environment friendly since no solvent was used in the deprotection process. The reaction conditions are mild and should be useful for the deprotection of MOM derivatives of complex and labile molecules.
- Pandurangan, Nanjan
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p. 231 - 235
(2017/07/15)
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- CLAISEN REARRANGEMENT OF ALLYL ARYL ETHERS CATALYSED BY ALKALINE-EARTH-METAL SALT
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Disclosed is an effective catalytic process for carrying out a Claisen rearrangement reaction, comprising reacting an allyl aryl ether in the presence of a metal salt catalyst, wherein the metal salt catalyst is an alkaline-earth-metal triflate salt or an alkaline-earth-metal triflimide salt, wherein the alkaline-earth-metal is selected from a group consisting of magnesium (Mg), calcium (Ca), strontium (Sr) and barium (Ba).
- -
-
Paragraph 0041
(2016/04/26)
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- Bismuth trichloride–mediated cleavage of phenolic methoxymethyl ethers
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A simple and efficient method for removal of phenolic methoxymethyl ethers in the presence of 30?mol% of bismuth trichloride in acetonitrile/water is described. Notable features of the cleavage protocol entail use of an ecofriendly bismuth reagent, ease of handling, low cost, operational simplicity, and good functional group compatibility. A number of structurally varied phenolic methoxymethyl ethers were cleaved in good to excellent yields.
- Obaro-Best, Oghale,Reed, Jack,Norfadilah, Alya A. F. B.,Monahan, Ryan,Sunasee, Rajesh
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supporting information
p. 586 - 593
(2016/06/08)
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- Eugenol synthesis method
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The invention belongs to the field of organic synthesis and particularly relates to a eugenol synthesis method. According to the eugenol synthesis method, guaiacol and allyl chloride are used as raw materials and are subjected to a catalytic reaction through a catalyst THLD to generate eugenol; an experiment testifies that the eugenol is synthesized by using the novel composite catalyst THLD, so that the conversion rate of the guaiacol and the yield of the eugenol are greatly improved, the conversion rate of the guaiacol reaches to 98 percent and the yield of the eugenol reaches to 88 percent.
- -
-
Paragraph 0042; 0043; 0044; 0045; 0046
(2016/10/08)
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- PROCESS FOR PREPARING SYNTHETIC PARA-EUGENOL
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Processes are provided for preparing synthetic para-eugenol and polysiloxane- polycarbonate copolymers including the synthetic para-eugenol. In an embodiment, a process for synthesizing para-eugenol can comprise: a) hydrolyzing methyl 5-allyl-3- methoxysalicylate to form 5-allyl-3-methoxysalicylic acid; b) decarboxylating the 5-allyl-3- methoxysalicylic acid to form a product comprising para-eugenol. The polysiloxane- polycarbonate copolymer prepared by the process may be isolated by, for example, anti- solvent precipitation followed by vacuum drying.
- -
-
Paragraph 0135-0136
(2015/02/25)
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- Mild and selective deprotection of tert -butyl(dimethyl)silyl ethers with catalytic amounts of sodium tetrachloroaurate(III) dihydrate
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A simple and mild method for the removal of tert-butyl(dimethyl)silyl (TBS) protecting groups with catalytic amounts of sodium tetrachloroaurate(III) dihydrate is described. The procedure permits selective deprotection of aliphatic TBS ethers in good to excellent yields in the presence of aromatic TBS ethers, aliphatic triisopropylsilyl ethers, aliphatic tert-butyl(diphenyl)silyl ethers, or sterically hindered aliphatic TBS ethers. Additionally, TBS ethers can also be transformed into 4-methoxybenzyl ethers or methyl ethers in one pot by using larger quantities of the catalyst and a higher reaction temperature.
- Zhang, Qi,Kang, Xiuqin,Long, Lei,Zhu, Lijuan,Chai, Yonghai
-
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- Catalytic depolymerization of alkali lignin in subcritical water: Influence of formic acid and Pd/C catalyst on the yields of liquid monomeric aromatic products
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Alkali lignin was subjected to depolymerization in subcritical water at 265 °C, 6.5 MPa for reaction times between 1-6 h in a batch reactor and in the presence of formic acid (FA) and Pd/C catalyst. The oil products were extracted into diethyl ether and contained >90% of single-ring phenolic compounds. The reaction of lignin in subcritical water alone yielded 22.3 wt% oil containing 56% guaiacol as the main product. A maximum oil yield of 33.1 wt% was obtained when the lignin was reacted in the presence of formic acid alone. In the presence of FA, catechol became the predominant compound, with more than 80% of the ether extract after 6 h. The conversion of guaiacol to catechol in the presence of formic acid suggested the hydrolysis of O-CH3 ether bonds. In addition, the yields of alkyl guaiacols increased in the presence of FA. The use of 5 wt% Pd/C catalyst with FA slightly decreased the yields of oil products but led to compounds indicative of hydrogenolysis of aryl-O ether bonds as well as hydrogenation of CC bonds.
- Onwudili, Jude A.,Williams, Paul T.
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p. 4740 - 4748
(2014/12/11)
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- Hydrazone-palladium-catalyzed allylic arylation of cinnamyloxyphenylboronic acid pinacol esters
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Allylic arylation of cinnamyloxyphenylboronic acid pinacol esters 3, which have arylboronic acid moiety and allylic ether moiety, using a hydrazone 1d-Pd(OAc)2 system proceeded and gave the corresponding 1,3-diarylpropene derivatives 4 with a phenolic hydroxyl group via a selective coupling reaction of the π-allyl intermediate to the boron-substituted position of the leaving group.
- Watanabe, Kohei,Mino, Takashi,Abe, Taichi,Kogure, Taketo,Sakamoto, Masami
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p. 6695 - 6702
(2014/08/05)
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- Ruthenium-catalyzed one-pot synthesis of (E)-(2-arylvinyl)boronates through an isomerization/cross-metathesis sequence from allyl-substituted aromatics
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We described the efficient preparation of (E)-(2-arylvinyl)boronates from allylbenzene derivatives on the basis of an isomerization/cross-metathesis sequence catalyzed by a modified Hoveyda-Grubbs catalyst. The implementation of the experimental procedure was simple and compatible with a large variety of substrates. This methodology provides a new chemical transformation not described to date. Allyl-substituted aromatics can thus be converted into diversely functionalized compounds, such as (E)-stilbene derivatives or (E)-vinyl azides, in only two steps. Copyright
- Hemelaere, Remy,Caijo, Frederic,Mauduit, Marc,Carreaux, Francois,Carboni, Bertrand
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supporting information
p. 3328 - 3333
(2014/06/09)
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- Allyl/propenyl phenol synthases from the creosote bush and engineering production of specialty/commodity chemicals, eugenol/isoeugenol, in Escherichia coli
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The creosote bush (Larrea tridentata) harbors members of the monolignol acyltransferase, allylphenol synthase, and propenylphenol synthase gene families, whose products together are able to catalyze distinct regiospecific conversions of various monolignols into their corresponding allyl- and propenyl-phenols, respectively. In this study, co-expression of a monolignol acyltransferase with either substrate versatile allylphenol or propenylphenol synthases in Escherichia coli established that various monolignol substrates were efficiently converted into their corresponding allyl/propenyl phenols, as well as providing proof of concept for efficacious conversion in a bacterial platform. This capability thus potentially provides an alternate source to these important plant phytochemicals, whether for flavor/fragrance and fine chemicals, or ultimately as commodities, e.g.; for renewable energy or other intermediate chemical purposes. Previous reports had indicated that specific and highly conserved amino acid residues 84 (Phe or Val) and 87 (Ile or Tyr) of two highly homologous allyl/propenyl phenol synthases (circa 96% identity) from a Clarkia species mainly dictate their distinct regiospecific catalyzed conversions to afford either allyl- or propenyl-phenols, respectively. However, several other allyl/propenyl phenol synthase homologs isolated by us have established that the two corresponding amino acid 84 and 87 residues are not, in fact, conserved.
- Kim, Sung-Jin,Vassao, Daniel G.,Moinuddin, Syed G.A.,Bedgar, Diana L.,Davin, Laurence B.,Lewis, Norman G.
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- Highly practical iron-catalyzed C-O cleavage reactions
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Facile iron-catalyzed cleavage of various allyl, cinnamyl and benzyl C-O linkages has been effected in the presence of ethylmagnesium chloride. The protocol is operationally simple (xylene-THF, r.t., 1 h), requires low catalyst loading (1 mol% FeCl2) and tolerates halides, esters, amines, ethers and olefins. The allyl moiety is converted to volatile hydrocarbons which renders laborious product separation unnecessary.
- Gaertner, Dominik,Konnerth, Hannelore,Von Wangelin, Axel Jacobi
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p. 2541 - 2545
(2013/09/24)
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- Synthesis and evaluation of antioxidant-S-(+)-ibuprofen hybrids as gastro sparing NSAIDs
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Ibuprofen is one of the most popular NSAIDs for the last three decades but also known for its gastrointestinal side effects similar to other NSAIDs. To overcome this problem, we have designed and synthesized ibuprofen - antioxidant (thymol, guaiacol, eugenol, and menthol) hybrids (6-13) with and without spacer as gastro sparing agents. The hybrids have been found to be chemically stable, biolabile and exhibited retention of anti-inflammatory and analgesic activity with significant reduced ulcerogenicity as compared to the ibuprofen and ibuprofen + antioxidant physical mixture. The absence of ulcerogenicity may be attributed to antioxidants and improved physicochemical properties of these hybrid molecules.
- Chandiran, Senthil,Vyas, Sandeep,Sharma, Neetika,Sharma, Manu
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p. 1006 - 1016
(2014/01/06)
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- Hydrogenolysis of lignosulfonate into phenols over heterogeneous nickel catalysts
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We report a strategy for the catalytic conversion of lignosulfonate into phenols over heterogeneous nickel catalysts. Aryl-alkyl bonds (C-O-C) and hydroxyl groups (-OH) are hydrogenated to phenols and alkanes, respectively, without disturbing the arenes. The catalyst is based on a naturally abundant element, and is recyclable and reusable. The Royal Society of Chemistry 2012.
- Song, Qi,Wang, Feng,Xu, Jie
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supporting information; scheme or table
p. 7019 - 7021
(2012/08/14)
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- Biotransformation of isoeugenol catalyzed by growing cells of Pseudomonas putida
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Growing cells of Pseudomonas putida transformed isoeugenol after 5 days of incubation to give mainly vanillin, eugenol, 4-(E)-(3-hydroxyprop-1-enyl)-2- methoxyphenol and the dimeric molecule (+)-4-[2,3-dihydro-7-methoxy-3-methyl-5- (E)-(1-propenyl)-2-benzofuranyl]-2-methoxyphenol (licarin A). The formation of the latter compound from isoeugenol by biotransformation with P. putida is reported here for the first time.
- Vasudevan, Sangeetha,Bhat, Sujata V.
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experimental part
p. 147 - 150
(2011/12/15)
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- Bifunctional Aryloxylate Esters as potential oxidatively cleavable linkers
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Selectively cleavable linkers are essential parts in environmentally responsive materials. Here, we introduce aryl oxalate esters (AOE) as one of the first examples for oxidatively cleavable linkers. To this end a series of novel AOEs was synthesized and explored regarding the H2O 2-dependent degradation. All AOEs were cleaved selectively at the oxalate group. The degradation rate was clearly dependent on the substituents. Further, it was found that the H2O2 based degradation undergoes an autocatalysis mechanism.
- Czarnecki,Kampert,Barbe,Tiller
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scheme or table
p. 3551 - 3554
(2011/07/29)
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- Selective O-deallylation of o-allyloxyanisoles
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o-Allyloxyanisoles are selectively and easily deallylated by treatment with sec- or tert-butyllithium at low temperature. The reaction is proposed to proceed through a tandem intermolecular carbolithiation-β;-elimination process, which can also be considered an SN2′ attack of the organolithium on the allyl ether.
- Sanz, Roberto,Martínez, Alberto,Marcos, César,Fa?ańas, Francisco J.
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experimental part
p. 1957 - 1960
(2009/05/26)
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- High-yielding cleavage of (aryloxy)acetates
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A reliable and high-yielding one-pot sequence for the removal of O-carboxymethyl moieties from phenols is presented. When diethylphosphoryl azide is employed as the azide transfer reagent in the Curtius rearrangement and glycerol in the subsequent hydrolytic workup, the protocol can be reliably applied to a very broad scope of substrates. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Spurg, Anke,Waldvogel, Siegfried R.
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p. 337 - 342
(2008/09/18)
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- Microwave-accelerated Claisen rearrangement in bicyclic imidazolium [b-3C-im][NTf2] ionic liquid
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With microwaves, a chemically stable ionic liquid [b-3C-im][NTf2] recently developed in our laboratory was used as solvent and successfully applied to accelerate Claisen rearrangement reactions at high temperatures. In the presence of Lewis acid MgCl2, these thermal rearrangements could be achieved in similar reaction times but at lower temperature. For the microwaved reactions studied in this work, without scarifying isolated yields, the reaction times were significantly reduced from hours (by conventional heating) to ≤3 min. Our result also demonstrated that [b-3C-im][NTf2] ionic liquid was a useful solvent substitute and could be recycled multiple times for the studied rearrangement reaction at elevated temperatures.
- Lin, Yung-Lun,Cheng, Jen-Yen,Chu, Yen-Ho
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p. 10949 - 10957
(2008/02/13)
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- Sodium dithionite initiated addition of 1-bromo-1-chloro-2,2,2-trifluoroethane to allylaromatics. Facile synthesis of conjugated dienes substituted with terminal CF3 group
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Sodium dithionite effectively promotes the addition of 1-bromo-1-chloro-2,2,2-trifluoroethane to the terminal double bond of allylbenzenes 1. The reactions proceeded in MeCN/H2O to give a 3:1 mole ratio of diastereoisomers of 1-(2-bromo-4-chloro-5,5,5-trifluoropentyl)benzenes 2 as the main products together with small amounts of its reductive debromination products 3. Total yields of 2 and 3 were dependent on the nature of the aromatic ring substituents in 1. Treatment of adducts 2 with DBU in refluxing hexanes resulted in double dehydrohalogenation affording, in good yields, conjugated dienes 4 (1,1,1-trifluoro-5-phenyl-2,4-pentadienes) terminated with the CF3 group at the one end and the phenyl group at the opposite end. These dienes were found to be sufficiently reactive to undergo Diels-Alder condensation with active dienophiles to give trifluoromethylated carbocycles. The reactions of CF3CHClBr with allylheterocycles were less successful and lead to low yields of mixtures of hardly separable compounds or to polymeric resins.
- Ignatowska, Jolanta,Dmowski, Wojciech
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p. 720 - 729
(2008/03/28)
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- Isolation and characterization of a β-primeverosidase-like enzyme from Penicillium multicolor
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p-Nitrophenyl and eugenyl β-primeveroside (6-O-β-D-xylopyranosyl- β-D-glucopyranoside) hydrolytic activity was found in culture filtrate from Penicillium multicolor IAM7153, and the enzyme was isolated. The enzyme was purified as a β-primeverosidase-like enzyme by precipitation with ammonium sulfate followed by successive chromatographies on Phenyl Sepharose, Mono Q, and β-galactosylamidine affinity columns. The molecular mass was estimated to be 50 kDa by SDS-PAGE and gel filtration. The purified enzyme was highly specific toward the substrate p-nitrophenyl β-primeveroside, which was cleaved in an endo-manner into primeverose and p-nitrophenol, but a series of β-primeveroside as aroma precursors were hydrolyzed only slightly as substrates for the enzyme. In analyses of its hydrolytic action and kinetics, the enzyme showed narrow substrate specificity with respect to the aglycon and glycon moieties of the diglycoside. We conclude that the present enzyme is a kind of β-diglycosidase rather than β-primeverosidase.
- Tsuruhami, Kazutaka,Mori, Shigeharu,Amarume, Satoshi,Saruwatari, Shigetaka,Murata, Takeomi,Hirakake, Jun,Sakata, Kanzo,Usui, Taichi
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p. 691 - 698
(2008/02/08)
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- AlCl3·6H2O/KI/CH3CN/H 2O: An efficient and versatile system for chemoselective C-O bond cleavage and formation of halides and carbonyl compounds from alcohols in hydrated media
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AlCl3·6H2O/KI/CH3CN/H 2O, an efficient and versatile system, cleaves the C-O bonds of esters, acetals, ethers, and oxathiolanes to the corresponding acids, alcohols, and carbonyl compounds chemoselectively at 80°C in hydrated media with good yields. This system also converts the alcohols (primary/secondary) to halides and oxidizes the alcohols (primary/secondary) to the corresponding carbonyl compounds in the presence of DMSO. Copyright Taylor & Francis Group, LLC.
- Gogoi, Pranjal,Konwar, Dilip,Sharma, Saikat Das,Gogoi, Prodip Kumar
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p. 1259 - 1264
(2007/10/03)
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- Synthesis, properties and microemulsion formulation of ibuprofen eugenol ester
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Ibuprofen-eugenol ester (IEE), a highly lipophilic compound, was synthesized from ibuprofen in order to reduce the common side effects induced by this classic anti-inflammatory drug. IEE was isolated as an amorphous whitish solid with a melting point at 40.2 ± 0.1 °C, whose structure was confirmed by IR, 1H. NMR and MS spectra. The hydrolysis results showed that the ester was stable over a wide pH range from 1.1 - 9.96. However, it could be hydrolyzed easily by enzymes from rat plasma and rat liver homogenate. A pharmaceutically acceptable microemulsion system was presented and characterized in terms of stability, droplet size distribution (DSD) and their solubilization capacity for IEE. The solubility of IEE in the optimized microemulsion formulation was about 21,000 times higher than that in water. The AUC of ibuprofen from the prodrug showed a remarkable increase compared to oral ibuprofen suspension. These results suggest that synthesizing the ibuprofen prodrug was justified and the presented microemulsion system might be a promising oral dosage form for poorly water-soluble drugs.
- Zhao,Chen,Gao,Luo,Li
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p. 883 - 887
(2007/10/03)
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- Expeditious synthesis of bioactive allylphenol constituents of the genus Piper through a metal-free photoallylation procedure
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Nine bioactive allylphenol (anisole) derivatives (e.g. eugenol, safrole and asaricin) present in several plants of the genus Piper have been synthesized in medium to high yield via aryl cation intermediates. This expeditious metal-free procedure involves the irradiation of the corresponding chlorophenols or chloroanisoles in a polar solvent (MeCN or, better, TFE or aqueous acetonitrile) in the presence of allyltrimethylsilane. Estragole has also been synthesized starting from the corresponding fluoroderivative and diazonium salt, though in a lower yield. The Royal Society of Chemistry 2005.
- Protti, Stefano,Fagnoni, Maurizio,Albini, Angelo
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p. 2868 - 2871
(2007/10/03)
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- Bismuth(III) triflate: Novel and efficient catalyst for Claisen and Fries rearrangements of allyl ethers and phenyl esters
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Bismuth(III) triflate catalyzed Claisen and Fries rearrangements of allyl phenyl ethers and phenyl acetates have been presented. The reaction proceeds smoothly and yields corresponding rearranged products in good yields. The bismuth triflate displays higher activity over the corresponding La, Yb, and Sc triflates.
- Sreedhar,Swapna,Sridhar
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p. 1433 - 1440
(2007/10/03)
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- Rhodium- and iridium-catalyzed allylation of electron-rich arenes with allyl tosylate
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The allylation of electron-rich arenes with allyl tosylate proceeded at 0°C in the presence of [Rh(nbd)(CH3CN)2]PF 6. Various oxygenated arenes were allylated with high para-selectivity in almost all cases. Especially in t
- Tsukada, Naofumi,Yagura, Yasushige,Sato, Tetsuo,Inoue, Yoshio
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p. 1431 - 1434
(2007/10/03)
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- Water-Accelerated Claisen Rearrangements
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Allyl aryl ethers undergo accelerated Claisen and [1,3] rearrangements in the presence of a mixture of trialkylalanes and water or aluminoxanes. The ratio of ortho-, meta-, and pora-Claisen products depends to a large extent on the presence of water and to a much lesser extent on the nature of the alane.
- Wipf, Peter,Rodriguez, Sonia
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p. 434 - 440
(2007/10/03)
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- Silicone functionalized eugenol esters
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This invention relates to composition of matter of certain euganol functionalized silicone polymers useful to make substantive antimicrobial agents. These compounds allow for the topical delivery of euganol to the skin surface, where it has a variety of desirable effects.
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- Alternative Lewis acids to effect Claisen rearrangement
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Yb(OTf)3 and DIBAL-H are developed as alternative Lewis acids for effecting Claisen rearrangement of allyl, crotyl and prenyl aryl ethers.
- Sharma,Ilangovan,Sreenivas, Punna,Mahalingam
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p. 615 - 618
(2007/10/03)
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- Fine particle and gaseous emission rates from residential wood combustion
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Residential wood combustion emissions were analyzed to determine emission rates and to develop chemical emissions profiles that represent the appliances and woods typically used in wood-burning-communities. Over 350 elements, inorganic compounds, and organic compounds were quantified. A range of 4-9 g/kg dry fuel of particulate matter(a dilution stack sampler equipped with a 2.5-μm particle selective cyclone. Emissions were diluted 20-70 times, cooled to ambient temperature, and allowed 80 s for condensation prior to collection. Wood type, wood moisture, burn rate, and fuel load were varied for different experiments. Fine particle and se mivolatile organic compounds were collected on filter/PUF/XAD/PUF cartridges. Inorganic samples and mass were collected on Teflon and quartz filters. Volatile organic carbon compounds were trapped with Tenax (C8- C20), canister (C2-C12), and 2,4-dinitrophenylhydrazine impregnated cartridges (carbonyl compounds). Analysis of particle and semivolatile organic species was conducted by gas chromatography/mass spectrometry. Teflon filters were analyzed for mass by gravimetry, trace elements were analyzed by X-ray fluorescence and ammonium was analyzed by automated colorimetry. Quartz filters were analyzed for organic and elemental carbon by thermal/optical reflectance, and forts were analyzed by ion chromatography. Select quartz filters were analyzed by accelerator mass spectrometry for carbon-12 and carbon-14 abundance. Canister and Tenax samples were analyzed by gas chromatography with a flame ionization detector, and carbonyl compounds were analyzed by high-performance liquid chromatography. Residential wood combustion emissions were analyzed to determine emission rates and to develop chemical emissions profiles that represent the appliances and woods typically used in wood-burning communities. Over 350 elements, inorganic compounds, and organic compounds were quantified. A range of 4-9 g/kg dry fuel of particulate matter (a dilution stack sampler equipped with a 2.5-μm particle selective cyclone. Emissions were diluted 20-70 times, cooled to ambient temperature, and allowed 80 s for condensation prior to collection. Wood type, wood moisture, burn rate, and fuel load were varied for different experiments. Fine particle and semivolatile organic compounds were collected on filter/PUF/XAD/PUF cartridges. Inorganic samples and mass were collected on Teflon and quartz filters. Volatile organic carbon compounds were trapped with Tenax (C8-C20), canister (C2-C12), and 2,4-dinitrophenylhydrazine impregnated cartridges (carbonyl compounds). Analysis of particle and semivolatile organic species was conducted by gas chromatography/mass spectrometry. Teflon filters were analyzed for mass by gravimetry, trace elements were analyzed by X-ray fluorescence, and ammonium was analyzed by automated colorimetry. Quartz filters were analyzed for organic and elemental carbon by thermal/optical reflectance, and ions were analyzed by ion chromatography. Select quartz filters were analyzed by accelerator mass spectrometry for carbon-12 and carbon-14 abundance. Canister and Tenax samples were analyzed by gas chromatography with a flame ionization detector, and carbonyl compounds were analyzed by high-performance liquid chromatography.
- Mcdonald, Jacob D.,Zielinska, Barbara,Fujita, Eric M.,Sagebiel, John C.,Chow, Judith C.,Watson, John G.
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p. 2080 - 2091
(2007/10/03)
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- Methoxyphenols from burning of Scandinavian forest plant materials
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Semivolatile compounds in smoke from gram-scale incomplete burning of plant materials were assessed by gas chromatography and mass spectrometry. Gas syringe sampling was shown to be adequate by comparison with adsorbent sampling. Methoxyphenols as well as 1,6-anhydroglucose were released in amounts as large as 10 mg kg-1 of dry biomass at 90% combustion efficiency. Wood, twigs, bark and needles from the conifers Norway spruce and Scots pine emitted 12 reported 2-methoxyphenols in similar proportions. Grass, heather and birchwood released the same 2-methoxyphenols but also the corresponding 2,6-dimethoxyphenols which are characteristic of angiosperms. The methoxyphenols are formed from lignin and differ in structure by the group in para position relative to the phenolic OH group. Prominent phenols were those with trans-l-propenyl and ethenyl groups in that position. Vanillin, 4- hydroxy-3-methoxybenzaldehyde, was a prominent carbonyl compound from the conifer materials. (C) 2000 Elsevier Science Ltd.
- Kjaellstrand, Jennica,Ramnaes, Olle,Petersson, Goeran
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p. 735 - 741
(2007/10/03)
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- Expedient and simple method for regeneration of alcohols from toluenesulfonates using Mg-MeOH
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Efficient conversion of toluenesulfonates to corresponding alcohols with Mg-MeOH is described.
- Sridhar, Madabhushi,Kumar, B. Ashok,Narender
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p. 2847 - 2850
(2007/10/03)
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- A general approach for the synthesis of phenolic natural products. Facile syntheses of grifolin and colletochlorins B and D
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A general approach is established for the synthesis of phenolic compounds having terpenoid side chains: (1) protection of the phenolic hydroxyls in the aromatic precursor by ether formation, (2) coupling the aromatic part with a terpenoid bromide, and (3) deprotection to regenerate the hydroxyl groups. This strategy was successfully applied to the synthesis of colletochlorins B and D and grifolin. Some of the colletochlorin derivatives were found to inhibit the cell growth of P388.
- Saimoto,Ueda,Sashiwa,Shigemasa,Hiyama
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p. 1178 - 1185
(2007/10/02)
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