- Electroreduction of m-Hydroxybenzoic Acid. Preparation of m-Phenoxybenzyl Alcohol for the New Insecticide Ethofenprox
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The electroreduction of m-hydroxybenzoic acid was examined from both mechanistic and technical points of view, and a practical route to m-phenoxybenzyl alcohol has been developed.
- Oi, Ryu,Shimakawa, Chitoshi,Shimokawa, Yasushi,Takenaka, Shinji
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Read Online
- Novel chemoselective reduction of aldehydes in the presence of other carbonyl moieties with thiourea dioxide
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Reduction of a variety of aldehydes in the presence of other carbonyl moieties to the corresponding alcohols occurs chemoselectively in high yields upon treatment with inexpensive reagent thiourea dioxide (TUDO) in aqueous alkali-ethanolic system for 2 h at 90°C. Copyright Taylor & Francis Group, LLC.
- Sambher, Shikha,Baskar, Chinnappan,Dhillon, Ranjit S.
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- Synthesis of unsymmetrical 5,6-POCOP′-type pincer complexes of nickel(II): Impact of nickelacycle size on structures and spectroscopic properties
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This report describes the synthesis and characterization of a family of unsymmetrical pincer complexes of nickel(ii), featuring both 5- and 6-membered nickelacycles. The room temperature reaction of NiBr2(NCCH3)x with bis(phosphinite) ligand, 1-(i-Pr2PO),3-(i-Pr2POCH2)-C6H4 (POCHOP′), results in direct nickelation at the 2-position of the aromatic ring to give (5,6-POCOP′)NiBr (5,6-POCOP′ = κP,κC,κP′-2-(i-Pr2PO),6-(i-Pr2POCH2)-C6H3). This complex undergoes salt metathesis reactions with M′X to give the corresponding charge neutral derivatives, (5,6-POCOP′)NiX (X = OSO2CF3, OSO2(4-CH3-C6H4), CH3, and CCCH3), whereas the abstraction of bromide by AgBPh4 in acetonitrile gave the cationic derivative, [(5,6-POCOP′)Ni(NCCH3)][BPh4]. The new complexes have been characterized by multinuclear NMR spectroscopy and X-ray diffraction studies. The reactivities of the new complexes (5,6-POCOP′)NiX (X = Br, OSO2CF3) have been explored briefly to establish the nucleophilicity of the X ligand and the substitutional lability of the phosphinite moiety in the 6-membered cycle.
- Salah, Abderrahmen,Corpet, Martin,Ul-Hassan Khan, Najm,Zargarian, Davit,Spasyuk, Denis M.
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Read Online
- Preparation method of benzoxaborole compound
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The invention discloses a preparation method of a benzoxaborole compound. The preparation method comprises the following steps: (1) reacting raw materials containing halogenated hydrocarbon and boric acid ester under an alkaline condition, acidifying and hydrolyzing to obtain an intermediate VI; and (2) reacting a raw material containing the intermediate VI with halogenated cyanophenyl to obtain the benzoxaborole compound. The raw materials are low in price, the preparation cost of the benzoxaborole compound is reduced, the steps of protection and de-protection of organic groups are not needed in the preparation process, the reaction process is simplified, and yield reduction caused by group protection is avoided; and meanwhile, the method is mild in reaction condition, low in equipment requirement and easy for large-scale industrial production.
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- Synthesis, crystal and structural characterization, Hirshfeld surface analysis and DFT calculations of three symmetrical and asymmetrical phosphonium salts
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Three stable phosphonium salts of 1,4-butanediylebis(triphenylphosphonium) dibromide I, butane-4?bromo-1-(triphenylphosphonium) bromide II and 1,3-propanediylbis(triphenylphosphonium) tetrahydroborate III were synthesized and structurally characterized. Single crystal X-ray diffraction analysis, spectroscopic methods and thermal analysis methods were used for the characterization of titled compounds. Crystallographic data showed that compound I crystallized in the triclinic crystal system with Pī space group and compound II crystallized in the monoclinic crystal system with P21/c space group. The crystal packing structures of I and II were stabilized by various intermolecular interactions, especially of C–H···π contacts. The molecular Hirshfeld surface analysis and 2D fingerprint revealed that the C···H contacts have 24.3% and 18.4% contributions in the crystal packings of compounds I and II, respectively. In addition, the H···Br (28.5%) contact has a considerable contribution to the crystal architecture of compound II. Theoretical studies were performed by DFT method to investigate the structural properties of the titled compounds. The isotopic ratio of boron in tetrahydroborate anion of compound III calculated by 1H NMR spectroscopy. The isotopic ratio for 10B/11B was 19.099 / 80.900%. Reduction of some carbonyl compounds to corresponding alcohols was performed by compound III and the optimum conditions were determined.
- Delaram, Behnaz,Gholizadeh, Mostafa,Makari, Faezeh,Nokhbeh, Seyed Reza,Salimi, Alireza
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- Whole seeds of Bauhinia variegata L. (Fabaceae) as an efficient biocatalyst for benzyl alcohol preparations from benzaldehydes
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Whole seeds of Bauhinia variegata L. (Fabaceae) were utilized as a biological reducer to transform benzaldehyde into benzyl alcohol. The effects of some variables such as temperature, the load of substrate and co-solvent, were established to optimize the reductive process. Utilizing the optimal reaction conditions, a laboratory-scale reaction (final concentration of the substrate: 21.2 mM) was performed to obtain benzyl alcohol (conversion: 95%; isolated yield: 49%; productivity: 1.11 g L?1 or 0.046 g L?1h?1 of benzyl alcohol). In addition, using these optimal conditions, fourteen substituted benzaldehydes were reduced, with a conversion achieved to their corresponding benzyl alcohols ranging from 62% to >99% (isolated yields from 7% to 70%). Moreover, useful building blocks by the synthesis of the drugs and important commercial products were also obtained. The scope, limitations and advantages of this new biocatalytic synthetic method are also discussed.
- Aimar, Mario L.,Bordón, Daniela L.,Díaz Panero, Mariángeles,Decarlini, María F.,Demmel, Gabriel I.,Rossi, Laura I.,Vázquez, Ana M.
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- α-D-Mannoside ligands with a valency ranging from one to three: Synthesis and hemagglutination inhibitory properties
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Six mono-, di-, and trivalent α-D-mannopyranosyl conjugates built on aromatic scaffolds were synthesized in excellent yields by Cu(I) catalyzed azide-alkyne cycloaddition reaction (CuAAC). These conjugates were designed to have unique, flexible tails that combine a mid-tail triazole ring, to interact with the tyrosine gate, with a terminal phenyl group armed with benzylic hydroxyl groups to avoid solubility problems as well as to provide options to connect to other supports. Biological evaluation of the prepared conjugates in hemagglutination inhibition (HAI) assay revealed that potency increases with valency and the trivalent ligand 6d (HAI = 0.005 mM) is approximately sevenfold better than the best meta-oriented monovalent analogues 2d and 4d (HAI ≈ 0.033 mM) and so may serve as a good starting point to find new lead ligands.
- Al-Mughaid, Hussein,Khazaaleh, Maha
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- Continuous Flow Preparation of (Hetero)benzylic Lithiums via Iodine-Lithium Exchange Reaction under Barbier Conditions
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Herein we report the generation of benzylic lithiums via an iodine-lithium exchange reaction on benzylic iodides performed in continuous flow using tBuLi as the exchange reagent. The resulting benzylic lithium species are trapped in situ by carbonyl electrophiles under Barbier conditions, resulting in benzylic secondary and tertiary alcohols. This flow procedure further allows the generation of highly reactive heterobenzylic lithium compounds, which are difficult to generate under batch conditions. A general scale-up was possible without further optimization.
- Weidmann, Niels,Harenberg, Johannes H.,Knochel, Paul
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supporting information
p. 5895 - 5899
(2020/08/12)
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- Mild-temperature hydrogenation of carbonyls over Co-ZIF-9 derived Co-ZIF-x nanoparticle catalyst
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Benzimidazole and metal cobalt salts were employed in the synthesis of Co-ZIF-9 by solvothermal crystallization. Highly active catalysts for selective hydrogenation of carbonyl compounds were developed. The optimal nanocatalyst Co-ZIF-350 manifested remarkable activity and selectivity for the hydrogenation of cyclohexanone under mild conditions. Catalytic conversion of cyclohexanone reached the highest over the catalyst of Co-ZIF-9-pyrolyzed at 350 °C for 2 h, in which the conversion of cyclohexanone was 100 % and the selectivity of cyclohexanol was ＞99 % at 50 °C. A wide scope of ketones/aromatic aldehydes could be selectively reduced to the corresponding alcohols with high yields. Importantly, the nanocatalyst Co-ZIF-350 presented good tolerance of substrates with various functional groups under mild conditions.
- Hu, Ao,Lu, Xinhuan,Pan, Haijun,Wang, Chenlong,Xia, Qinghua,Xia, Yongde,Yang, Lu,Yue, Fanfan,Zhang, Haifu,Zhou, Dan
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- A is by aromatic carboxylic acid non-catalytic reaction of alcohol compound (by machine translation)
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The present invention discloses a non-catalytic reaction of the aromatic carboxylic acid preparation of alcohol compound. In an inert gas atmosphere, after dehydration and deoxidation treatment of the reaction bottle [...] borane and carboxylic acid stirring and mixing, reaction 6 - 12 hours to obtain borate, further hydrolyzed into alcohol; said carboxylic acid is benzoic acid, 4 - bromobenzoic acid, 4 - fluoro benzoic acid, 1 - naphthoic acid, 2 - methoxybenzene formic acid and the like. The invention for the first time in the absence of catalyst under the conditions of high-efficiently using carboxylic acid with borane generating borohydrite reaction, carbonyl compound with borane generating borohydrite reaction preparation borate, further hydrolysis alcohol, provides new programme. (by machine translation)
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Paragraph 0031
(2019/04/17)
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- Synthetic Versatility of Lipases: Application for Si-O Bond Formation and Cleavage
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Several commercially available lipases were examined in a study on O-Si bond formation and cleavage applying silicon-based protecting groups and alcohols or the corresponding silyl ethers. With regard to deprotection, from silyl ether to the corresponding alcohol, only the solvent and the lipase were necessary. The influence of the protecting group, the lipase source, and the substituent was investigated to optimize the results. The TMS moiety could be removed in 24 hours of reaction at room temperature in aqueous systems (conv. up to 99%, depending on the substrate and lipase). The reverse reactions, that is, with the protection of the alcohols, were carried out in hexane using different silyl chlorides. The TMS, TES, and TBS moieties were successfully inserted in the primary and secondary alcohols without the need for dry conditions or an inert atmosphere, presenting conversions of up to 99%, depending on the substrate.
- Brondani, Patrícia Bulegon,Mittersteiner, Mateus,Voigt, Morgana Aline,Klinkowski, Bruna Heloisa,Riva Scharf, Dilamara,De Jesus, Paulo Cesar
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supporting information
p. 477 - 485
(2019/01/10)
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- A novel hydroxy-bisphosphonic acid prodrug as a candidate for the delivery of ibuprofen to bone
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Active targeting with controlled delivery of anti-inflammatory drugs to the bone is not sufficiently explored. In this study, concise and novel synthesis of a hydroxy-bisphosphonic acid (HBPA) prodrug containing ibuprofen is described. The key step consisted of preparing the HBPA function from a carboxylic acid precursor, in mild conditions and using appropriate Arbuzov reactions with tris(trimethylsilyl)phosphite. This prodrug would be an excellent candidate for the treatment of bone inflammation diseases such as rheumatoid arthritis.
- Aoun, Sameh,Bennour, Haythem
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supporting information
p. 3412 - 3418
(2019/11/03)
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- Linear and Convergent Syntheses of Bifunctional Hydroxy-Bisphosphonic Compounds as Potential Bone-Targeting Prodrugs
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The synthesis of two bifunctional compounds bearing a terminal hydroxy-bisphosphonic function (HBP) was achieved following a linear and a convergent strategy. In the linear approach, the free hydroxy-bisphosphonic function was introduced in the last step of the synthesis, under neutral conditions using an Arbuzov reaction with tris(trimethylsilyl) phosphite and a carboxylic acid precursor activated in situ with catecholborane. In the convergent approach, Huisgen type cycloaddition was studied starting from an HBP-functionalized alkyne partner to obtain the targeted bifunctional molecule. These complementary approaches allow for the preparation of complex bone-targeting molecules as potential prodrug candidates.
- Aoun, Sameh,Lebreton, Jacques,Mathé-Allainmat, Monique,Sierocki, Pierre
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p. 3556 - 3566
(2019/09/07)
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- Identification of 5-Substituted 2-Acylaminothiazoles That Activate Tat-Mediated Transcription in HIV-1 Latency Models
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The persistent reservoir of cells latently infected with human immunodeficiency virus (HIV)-integrated proviral DNA necessitates lifelong suppressive antiretroviral therapy (ART). Epigenetic targeted compounds have shown promise as potential latency-reversing agents; however, these drugs have undesirable toxicity and lack specificity for HIV. We utilized a novel HEK293-derived FlpIn dual-reporter cell line, which quantifies specific HIV provirus reactivation (LTR promoter) relative to nonspecific host cell gene expression (CMV promoter), to identify the 5-substituted 2-acylaminothiazole hit class. Here, we describe the optimization of the hit class, defining the functionality necessary for HIV gene activation and for improving in vitro metabolism and solubility. The optimized compounds displayed enhanced HIV gene expression in HEK293 and Jurkat 10.6 latency cellular models and increased unspliced HIV RNA in resting CD4+ T cells isolated from HIV-infected individuals on ART, demonstrating the potential of the 2-acylaminothiazole class as latency-reversing agents.
- Nguyen, William,Jacobson, Jonathan,Jarman, Kate E.,Jousset Sabroux, Helene,Harty, Leigh,McMahon, James,Lewin, Sharon R.,Purcell, Damian F.,Sleebs, Brad E.
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p. 5148 - 5175
(2019/05/28)
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- Polypyridyl iridium(III) based catalysts for highly chemoselective hydrogenation of aldehydes
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Iridium-catalyzed transfer hydrogenation (TH) of carbonyl compounds using HCOOR (R = H, Na, NH4) as a hydrogen source is a pivotal process as it provides the clean process and is easy to execute. However, the existing highly efficient iridium catalysts work at a narrow pH; thus, does not apply to a wide variety of substrates. Therefore, the development of a new catalyst which works at a broad pH range is essential as it can gain a broader scope of utilization. Here we report highly efficient polypyridyl iridium(III) catalysts, [Ir(tpy)(L)Cl](PF6)2 {where tpy = 2,2′:6′,2′'-Terpyridine, L = phen (1,10-Phenanthroline), Me2phen (4,7-Dimethyl-1,10-phenanthroline), Me4phen (3,4,7,8-Tetramethyl-1,10-phenanthroline), Me2bpy (4,4′-Dimethyl-2–2′-dipyridyl)} for the chemoselective reduction of aldehydes to alcohols in aqueous ethanol and sodium formate as the hydride source. The reaction can be carried out efficiently in broad pH ranges, from pH 6 to 11. These catalysts are air stable, easy to prepare using commercially available starting materials, and are highly applicable for a wide range of substrates, such as electron-rich or deficient (hetero)arenes, halogens, phenols, alkoxy, ketones, esters, carboxylic acids, cyano, and nitro groups. Particularly, acid and hydroxy groups containing aldehydes were reduced successfully in basic and acidic reaction conditions, demonstrating the efficiency of the catalyst in a broad pH range with high conversion rates under microwave irradiation.
- Pandrala, Mallesh,Resendez, Angel,Malhotra, Sanjay V.
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p. 283 - 288
(2019/09/30)
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- Mild palladium-catalysed highly efficient hydrogenation of CN, C-NO2, and CO bonds using H2 of 1 atm in H2O
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Here we present the first example of a mild and high-efficiency protocol enabling a process in water using 1 atm of H2 for the efficient and selective hydrogenation of nitriles, nitro compounds, ketones, and aldehydes to yield primary amines and alcohols with satisfactory yields of up to >99%. Several palladium-based nanoparticle catalysts were prepared from K2PdCl4 and ligands, and one of them was found to be the best and most suitable for the hydrogenation of CN, C-NO2, and CO bonds. In addition, the catalyst Pd-NPs can be easily recycled and reused without losing their activity and selectivity. A plausible mechanism for the hydrogenation of a CN bond was also proposed, representing the first example that possesses great potential for sustainable industrial purposes.
- Liu, Yaxu,He, Shaopo,Quan, Ziyi,Cai, Huizhuo,Zhao, Yang,Wang, Bo
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supporting information
p. 830 - 838
(2019/02/27)
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- Temperature-Directed Biocatalysis for the Sustainable Production of Aromatic Aldehydes or Alcohols
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The biosynthesis of aromatic aldehydes and alcohols from renewable resources is currently receiving considerable attention because of an increase in demand, finite fossil resources, and growing environmental concerns. Here, a temperature-directed whole-cell catalyst was developed by using two novel enzymes from a thermophilic actinomycete. Ferulic acid, a model lignin derivative, was efficiently converted into vanillyl alcohol at a reaction temperature at 30 °C. However, when the temperature was increased to 50 °C, ferulic acid was mainly converted into vanillin with a productivity of 1.1 g L?1 h?1. This is due to the fact that the redundant endogenous alcohol dehydrogenases (ADHs) are not active at this temperature while the functional enzymes from the thermophilic strain remain active. As the biocatalyst could convert many other renewable cinnamic acid derivatives into their corresponding aromatic aldehydes/alcohols, this novel strategy may be extended to generate a vast array of valuable aldehydes or alcohols.
- Ni, Jun,Gao, Yan-Yan,Tao, Fei,Liu, Hong-Yu,Xu, Ping
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supporting information
p. 1214 - 1217
(2018/01/27)
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- Efficient hydroboration of carbonyls by an iron(II) amide catalyst
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An easily prepared iron(ii) amide precatalyst enables the selective hydroboration of carbonyls with HBpin (pinacolborane) in the absence of any additive. The reactions proceed with low catalytic loading (1-3 mol%) under mild reaction conditions and display wide functional group compatibility. Aldehydes are selectively hydroborated in the presence of other reducible functional groups, such as ketones, alkenes, nitriles, esters, amides, acids and halides.
- Baishya, Ashim,Baruah, Swavalina,Geetharani
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supporting information
p. 9231 - 9236
(2018/07/29)
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- COMPOSITIONS AND METHODS FOR REDUCTION OF KETONES, ALDEHYDES AND IMINIUMS, AND PRODUCTS PRODUCED THEREBY
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A method of producing an alcohol, comprises reducing an aldehyde or a ketone with a hydridosilatrane. The reducing is carried out with an activator.
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Paragraph 0076-0077
(2018/01/20)
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- Aqueous Oxidations Started by TiO2 Photoinduced Holes Can Be a Rate-Determining Step
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In aqueous TiO2 photocatalytic hydroxylation of weakly polar aromatics, a series of inverse H/D KIEs of 0.7–0.8 were observed, which is different than the normal H/D kinetic isotope effects (KIEs) usually observed for polar aromatics. This result indicated that the oxidation started by photo-induced hvb + can be the rate-determining step.
- Gong, Yuanzheng,Yang, Chun,Ji, Hongwei,Chen, Chuncheng,Ma, Wanhong,Zhao, Jincai
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supporting information
p. 2048 - 2051
(2017/08/23)
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- Selective oxidation of aliphatic C-H bonds in alkylphenols by a chemomimetic biocatalytic system
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Selective oxidation of aliphatic C-H bonds in alkylphenols serves significant roles not only in generation of functionalized intermediates that can be used to synthesize diverse downstream chemical products, but also in biological degradation of these environmentally hazardous compounds. Chemo-, regio-, and stereoselectivity; controllability; and environmental impact represent the major challenges for chemical oxidation of alkylphenols. Here, we report the development of a unique chemomimetic biocatalytic system originated from the Gram-positive bacterium Corynebacterium glutamicum. The system consisting of CreHI (for installation of a phosphate directing/ anchoring group), CreJEF/CreG/CreC (for oxidation of alkylphenols), and CreD (for directing/anchoring group offloading) is able to selectively oxidize the aliphatic C-H bonds of p-And m-Alkylated phenols in a controllable manner. Moreover, the crystal structures of the central P450 biocatalyst CreJ in complex with two representative substrates provide significant structural insights into its substrate flexibility and reaction selectivity.
- Du, Lei,Dong, Sheng,Zhang, Xingwang,Jiang, Chengying,Chen, Jingfei,Yao, Lishan,Wang, Xiao,Wan, Xiaobo,Liu, Xi,Wangi, Xinquan,Huang, Shaohua,Cui, Qiu,Feng, Yingang,Liu, Shuang-Jiang,Li, Shengying
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p. E5129 - E5137
(2017/07/04)
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- Zinc-Mediated Efficient and Selective Reduction of Carbonyl Compounds
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We herein describe for the first time that an optimized combination of Zn and NH4Cl can be used for the selective reduction of aldehydes and ketones to the corresponding alcohols. The aldehyde and keto groups are selectively reduced in the presence of azide, cyano, epoxy, ester, and carbon–carbon double-bond functional groups. A broad functional-group compatibility, chemoselective reduction of aldehydes in the presence of ketones, and selective reduction of isatins at the C3 carbonyl group are the highlights of the present method.
- Mandal, Tirtha,Jana, Snehasish,Dash, Jyotirmayee
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p. 4972 - 4983
(2017/09/13)
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- METHOD TO PREPARE PHENOLICS FROM BIOMASS
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The present invention is directed to a method for preparing a final phenolic product from biomass comprising the steps of providing a furanic compound obtainable from biomass; reacting the furanic compound with a dienophile to obtain a phenolic compound; reacting the phenolic compound further to obtain the final phenolic product.
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Page/Page column 44; 45
(2016/08/10)
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- CSJ acting as a versatile highly efficient greener resource for organic transformations
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Simple, new, greener and efficient alternatives to the existing protocols have been developed for the reduction of aromatic aldehydes to their corresponding alcohols, decarboxylation of substituted benzoic acids (C6-C1) and substituted cinnamic acids (C6-C3) with a hydroxyl group at the para position with respect to the acid group to corresponding phenolic compounds and vinyl phenols respectively by using a natural feedstock, cucumber juice (CSJ), which acts as a greener solvent system, performing a substrate-selective reaction. Additionally, the hydrolysis of the acetyl as well as the benzoyl group of aromatic compounds has been carried out to afford excellent yield by CSJ.
- Maity, Himadri Sekhar,Misra, Kaushik,Mahata, Tanushree,Nag, Ahindra
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p. 24446 - 24450
(2016/03/15)
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- Silatrane as a Practical and Selective Reagent for the Reduction of Aryl Aldehydes to Benzylic Alcohols
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Hydrosilanes are cheap, readily available substrates, yet they do not see as extensive use for simple carbonyl reductions as borohydrides. Hydrosilane reducing agents broadly fall into one of two general categories: either a) they are easy to handle and require expensive and/or hazardous additives, or b) they are difficult and/or dangerous to handle. This work details the discovery of mild and functional group compatible conditions utilizing hydrosilatrane for the selective reduction of aryl aldehydes to benzylic alcohols without unwanted formation of ethers or deoxygenated products. This method offers significant advances in silane reductions as silatrane is an air- and moisture-stable yet relatively reactive reducing agent that can be used in benchtop open air reactions.
- Skrypai, Vladislav,Hurley, Joseph J. M.,Adler, Marc J.
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supporting information
p. 2207 - 2211
(2016/05/09)
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- Hydrogenation of carboxylic acids with a homogeneous cobalt catalyst
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The reduction of esters and carboxylic acids to alcohols is a highly relevant conversion for the pharmaceutical and fine-chemical industries and for biomass conversion. It is commonly performed using stoichiometric reagents, and the catalytic hydrogenation of the acids previously required precious metals. Here we report the homogeneously catalyzed hydrogenation of carboxylic acids to alcohols using earth-abundant cobalt. This system, which pairs Co(BF4)2·6H2O with a tridentate phosphine ligand, can reduce a wide range of esters and carboxylic acids under relatively mild conditions (100°C, 80 bar H2) and reaches turnover numbers of up to 8000.
- Korstanje, Ties J.,Van Der Vlugt, Jarl Ivar,Elsevier, Cornelis J.,De Bruin, Bas
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p. 298 - 302
(2015/10/29)
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- Highly chemoselective hydrogenation of active benzaldehydes to benzyl alcohols catalyzed by bimetallic nanoparticles
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By using novel Pd/Ni bimetallic nanoparticles as a catalyst, the active benzaldehydes were hydrogenated to the corresponding benzyl alcohols as unique products in practical quantitative yields. The undesired catalytic hydrogenolysis of the benzyl alcohol was inhibited completely. By using this hydrogenation as a key step, the total synthesis of the natural product gastrodin was achieved with less total steps and a higher total yield.
- Liu, Chulong,Bao, Hailin,Wang, Dingsheng,Wang, Xinyan,Li, Yadong,Hu, Yuefei
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p. 6460 - 6462
(2015/11/16)
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- A General, Practical Triethylborane-Catalyzed Reduction of Carbonyl Functions to Alcohols
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A combination of the abundant and low-cost triethylborane and sodium alkoxide generates a highly efficient catalyst for reduction of esters, as well as ketones and aldehydes, to alcohols using an inexpensive hydrosilane under mild conditions. The catalyst system exhibits excellent chemoselectivity and a high level of functional group tolerance. Mechanistic studies revealed a resting state of sodium triethylalkoxylborate that is the product of the reaction of BEt3 with sodium alkoxide. This borate species reacts with hydrosilane to form NaBEt3H, which rapidly reduces esters.
- Peng, Dongjie,Zhang, Mintao,Huang, Zheng
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supporting information
p. 14737 - 14741
(2015/10/19)
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- Synthesis and catalytic activity of water-soluble ruthenium(II) complexes bearing a naphthyridine-carboxylate ligand
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The synthesis of water-soluble (η6-arene)ruthenium(II) complexes based on pyrazolyl-naphthyridine ligands modified with a carboxylate group is reported. The complexes are easily accessible in good yields via complexation of [(arene)RuCl2]2 with 7-pyrazolyl-1,8- naphthyridine-2-carboxylic acid (1). All complexes have been characterized by spectroscopic and elemental analyses. The complexes {[Ru(η6- arene)(N,N′-1)Cl]Cl} (arene = benzene (5), p-cymene (6)) were further confirmed by X-ray diffraction studies. These complexes are soluble in water (ca. 10 mg/mL) and are catalytically active in hydrogen-transfer reduction of carbonyl compounds in aqueous medium with the use of HCOOH/HCOONa as the hydrogen source.
- Huang, Chang-Yao,Kuan, Kai-Yuan,Liu, Yi-Hong,Peng, Shie-Ming,Liu, Shiuh-Tzung
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p. 2831 - 2836
(2014/06/24)
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- Electrophilicity and nucleophilicity of commonly used aldehydes
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The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
- Pratihar, Sanjay
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p. 5781 - 5788
(2014/07/22)
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- N-ARYLYLMETHYLINDAZOLE MODULATORS OF PPARG
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The invention provides molecular entities that bind with high affinity to PPARG (PPARy), inhibit cdJk5-mediated phosphorylation of PP ARG, but do not exert an agonistic effect on PPARG. Compounds of the invention can be used for treatment of conditions in patients wherein PPARG plays a role, such as diabetes or obesity. Methods of preparation of the compounds, bioassay methods for evaluating compounds of the invention as non-agonistic PPARG binding compounds, and pharmaceutical compositions are also provided.
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Page/Page column 109; 110
(2013/06/06)
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- Base-catalyzed direct transformation of benzylamines into benzyl alcohols
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Benzylamines were directly transformed into benzyl alcohols in superheated aqueous methanol in the presence of a base catalyst. This process is simple and will provide an alternative industrial route to benzyl alcohols such as xylene glycols. Georg Thieme Verlag Stuttgart · New York.
- Kanbara, Yutaka,Abe, Takafumi,Fushimi, Norio,Ikeno, Taketo
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supporting information; experimental part
p. 706 - 710
(2012/07/01)
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- Palladium-catalyzed direct hydroxymethylation of aryl halides and triflates with potassium acetoxymethyltrifluoroborate
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Suzuki-Miyaura cross-coupling reactions of aryl halides and triflates with potassium acetoxymethyltrifluoroborate afforded the corresponding aryl and heteroaryl methanol products in moderate to excellent yields.
- Murai, Norio,Yonaga, Masahiro,Tanaka, Keigo
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supporting information; experimental part
p. 1278 - 1281
(2012/04/23)
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- New greener alternatives for bioreduction of aromatic aldehydes and decarboxylation of aromatic acids using juice of fruits
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Cocos nucifera L. and Borassus flabellifer L. juices act as bio catalytic system for the reduction of aromatic aldehydes to alcohols and selective decarboxylation of substituted cinnamic acid to styrene and substituted benzoic acid to polyphenolic compound. Both juices exhibit good activity when aromatic aldehydes and aromatic acids contain electron-donating groups at specific positions. Moreover, C. nucifera juice exhibits good result for the reduction and decarboxylation properties than B. flabellifer juice under the same reaction condition.
- Misra, Kaushik,Maity, Himadri Sekhar,Chanda, Subhankar,Nag, Ahindra
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experimental part
p. 92 - 95
(2012/09/22)
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- Nickel phthalocyanine assisted highly efficient and selective carbonyl reduction in polyethylene glycol-400
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Nickel phthalocyanine with polyethylene glycol- 400 is described as a reusable green catalytic system for highly chemo- and regioselective reduction of carbonyl compounds to corresponding alcohols at room temperature. The catalytic system showed wide substrate scope covering aromatic, hetero aromatic and aliphatic carbonyl compounds with high turnover number and frequency. In the present study, 1,3- and 1,4-benzenedicarbaldehydes have been regioselectively reduced to corresponding alcohols for the first time. The catalyst was reused up to seven times without any significance loss in activity. Springer Science+Business Media, LLC 2012.
- Verma, Praveen Kumar,Sharma, Upendra,Kumar, Neeraj,Bala, Manju,Kumar, Vishal,Singh, Bikram
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experimental part
p. 907 - 913
(2012/10/07)
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- CuI-catalyzed hydroxylation of aryl bromides under the assistance of 5-bromo-2-(1H-imidazol-2-yl)pyridine and related ligands
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A number of substituted 2-pyridin-2-yl-1H-benzoimidazoles and 2-(1H-imidazol-2-yl)pyridines were screened for promoting CuI-catalyzed hydroxylation of aryl bromides, which led to the discovery of the combination of CuI and 5-bromo-2-(1H-imidazol-2-yl)pyridine as an effective catalytic system for this transformation. Both electron-rich and electronic-deficient aryl bromides could be converted into the corresponding substituted phenols in good to excellent yields.
- Jia, Jianhuan,Jiang, Chenglin,Zhang, Xiaojing,Jiang, Yongwen,Ma, Dawei
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supporting information; experimental part
p. 5593 - 5595
(2011/11/06)
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- Selective photocatalytic oxidation of alcohols to aldehydes in water by TiO2 partially coated with WO3
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Semiconductor TiO2 particles loaded with WO3 (WO 3/TiO2), synthesized by impregnation of tungstic acid followed by calcination, were used for photocatalytic oxidation of alcohols in water with molecular oxygen under irradiation at I>350 nm. The WO 3/TiO2 catalysts promote selective oxidation of alcohols to aldehydes and show higher catalytic activity than pure TiO2. In particular, a catalyst loading 7.6 wt% WO3 led to higher aldehyde selectivity than previously reported photocatalytic systems. The high aldehyde selectivity arises because subsequent photocatalytic decomposition of the formed aldehyde is suppressed on the catalyst. The TiO2 surface of the catalyst, which is active for oxidation, is partially coated by the WO 3 layer, which leads to a decrease in the amount of formed aldehyde adsorbed on the TiO2 surface. This suppresses subsequent decomposition of the aldehyde on the TiO2 surface and results in high aldehyde selectivity. The WO3/TiO2 catalyst can selectively oxidize various aromatic alcohols and is reusable without loss of catalytic activity or selectivity.
- Tsukamoto, Daijiro,Ikeda, Makoto,Shiraishi, Yasuhiro,Hara, Takayoshi,Ichikuni, Nobuyuki,Tanaka, Shunsuke,Hirai, Takayuki
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experimental part
p. 9816 - 9824
(2011/10/08)
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- Furoxan nitric oxide donor coupled chrysin derivatives: Synthesis and vasculoprotection
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A series of furoxan-based nitric oxide-releasing chrysin derivatives were synthesized. Pharmacological assays indicated that all chrysin derivatives exhibited in vitro inhibitory activities against aldose reductase and advanced glycation end-product formation. Some chrysin derivatives were also found to increase the glucose consumption of HepG2 cells. Furthermore, the compounds released a low amount of NO in the presence of l-cysteine (range from 0.20% to 1.89%). These hybrid furoxan-based NO donor chrysin derivatives offer a mutual prodrug design concept for the development of therapeutic or preventive agents for vascular complications due to diabetes.
- Zou, Xiao-Qing,Peng, Sheng-Ming,Hu, Chang-Ping,Tan, Li-Feng,Deng, Han-Wu,Li, Yuan-Jian
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scheme or table
p. 1222 - 1226
(2011/04/18)
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- An efficient synthesis of phenol via CuI/8-hydroxyquinoline-catalyzed hydroxylation of aryl halides and potassium hydroxide
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The CuI/8-hydroxyquinoline-catalyzed direct hydroxylation of aryl iodides with KOH takes place at 100 C in a mixed solvent system (t-BuOH-DMSO-H 2O), providing the corresponding phenols in great diversity. Aryl bromides are found to be rather less reactive under these reaction conditions. Georg Thieme Verlag Stuttgart - New York.
- Maurer, Stefan,Liu, Wei,Zhang, Xiaojing,Jiang, Yongwen,Ma, Dawei
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supporting information; experimental part
p. 976 - 978
(2010/07/10)
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- HYDROXY-BISPHOSPHONIC ACID DERIVATIVES AS VECTOR TARGETING BONE TISSUE
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The present invention relates to hydroxy-bisphosphonic acid derivatives corresponding to general formula (I): in which: -n and m denote, independently of one another, an integer ranging from 1 to 4, —X denotes an oxygen atom or an N—R3 group, —R1 and R3 denote, independently of one another, a linear or branched C1 to C6 alkyl group, and —R2 denotes a residue of a molecule of therapeutic or diagnostic interest, or pharmaceutically acceptable salts of said derivatives, and also the method for the preparation thereof and the therapeutic or diagnostic use thereof.
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Page/Page column 6-7
(2010/12/29)
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- Synthesis of phenol, aromatic ether, and benzofuran derivatives by copper-catalyzed hydroxylation of aryl halides
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A smooth operator: The copper-catalyzed synthesis of phenols from aryl halides was carried out under relatively mild reaction conditions. Alkyl aryl ethers and benzofurans could also be prepared smoothly by one-pot domino protocols based on hydroxylation of aryl iodides (see scheme).
- Zhao, Dongbing,Wu, Ningjie,Zhang, Shuai,Xi, Peihua,Su, Xiaoyu,Lan, Jingbo,You, Jingsong
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supporting information; experimental part
p. 8729 - 8732
(2010/01/16)
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- A convenient method to reduce hydroxyl-substituted aromatic carboxylic acid with NaBH4/Me2SO4/B(OMe)3
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The reduction of hydroxyl-substituted aromatic carboxylic acid with NaBH4/Me2SO4/B(OMe)3 is described. Borane is generated by the reaction of NaBH4 with Me2SO4 in THF, which is as efficient as the commercial one. B(OMe)3 has been successfully applied to increase the reactivity and selectivity of this reaction. The optimum ratio of borane/B(OMe)3/acid is studied, and a variety of hydroxyl-substituted aromatic acids are reduced in good yields.
- Zhou, Yuhan,Gao, Guchao,Li, Hui,Qu, Jingping
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p. 3260 - 3263
(2008/09/20)
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- Efficient method for the reduction of carbonyl compounds by triethylsilane catalyzed by PdCl2
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The versatility of the palladium(II) chloride and triethylsilane system has been tested in the reduction of aromatic carbonyl compounds. The reaction takes place under mild conditions. This facile and efficient method affords high yields for the reduction of aldehydes and ketones to the corresponding alkanes.
- Mirza-Aghayan, Maryam,Boukherroub, Rabah,Rahimifard, Mahshid
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scheme or table
p. 3567 - 3570
(2009/02/07)
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- The oxa-Pictet-Spengler reaction: A highlight on the different efficiency between isochroman and phthalan or homoisochroman derivative syntheses
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Recently we reported that 6-hydroxy- and 6,7-dihydroxy-isochromans can be obtained under very mild conditions and with very good yield by a one-pot synthesis based on a modified oxa-Pictet-Spengler reaction. In this paper, we demonstrate that the above reaction is also useful for the synthesis of hydroxyphthalans, and we discuss the effects of the substituents on the alcoholic aromatic ring on the course of the reaction, as well as those on the aldehydic structure. We also report a synthesis of hydroxyhomoisochromans performed by the same method. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Guiso, Marcella,Betrow, Abduelhakem,Marra, Carolina
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experimental part
p. 1967 - 1976
(2009/04/04)
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- Synthesis and immunosuppressive activity of new artemisinin derivatives. Part 2: 2-[12(β or α)-Dihydroartemisinoxymethyl(or 1′-ethyl)]phenoxyl propionic acids and esters
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Another series of novel dihydroartemisinin derivatives were synthesized and assessed for their cytotoxicity of lymphocyte, inhibitory activity on mitogen-induced spleen lymphocyte proliferation in vitro. Some of the compounds exhibited inhibitory effects on ConA-induced T cell and LPS-induced B cell proliferation comparable to or more potent than parent artemisinin.
- Yang, Zhong-Shun,Wang, Jun-Xia,Zhou, Yu,Zuo, Jian-Ping,Li, Ying
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p. 8043 - 8049
(2007/10/03)
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- Sodium borohydride - Ammonium carbonate: An effective reducing system for aldehydes and ketones
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Reduction of aldehydes and ketones to the corresponding alcohols was achieved in a simple procedure using the system sodium borohydride and ammonium carbonate. This system needs lower excesses of reducing agent and leads to significantly shortened reaction times. Springer-Verlag 2005.
- Mohanazadeh, Farajollah,Hosini, Mostafa,Tajbakhsh, Mahmoud
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p. 2041 - 2043
(2007/10/03)
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- A mild deprotection strategy for allyl-protecting groups and its implications in sequence specific dendrimer synthesis
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A mild deprotection strategy for allyl ethers under basic conditions in the presence of a palladium catalyst is described. Under these conditions, aryl allyl ethers can be cleaved selectively in the presence of alkyl allyl ethers. These conditions are also effective in the deprotection of allyloxycarbonyl groups. The utility of the current methodology in sequence specific dendrimer synthesis is demonstrated.
- Vutukuri, Dharma Rao,Bharathi, Pandi,Yu, Zhouying,Rajasekaran, Karthik,Tran, My-Huyen,Thayumanavan
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p. 1146 - 1149
(2007/10/03)
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- N-methylpyrrolidine-zinc borohydride: As a new stable and efficient reducing agent in organic synthesis
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N-Methylpyrrolidine-zinc borohydride is readily prepared and used for reduction of a variety of organic compounds such as aldehydes, ketones, acid chlorides, and esters. Reactions are performed in THF at room temperature or under reflux condition and the yields are good to excellent. Complete regio-selectivity are observed in reduction of α,β-unsaturated carbonyl compounds.
- Tajbakhsh,Lakouraj,Mohanazadeh,Ahmadi-Nejhad
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p. 229 - 236
(2007/10/03)
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- Process for the preparation of 3-hydroxybenzyl alcohol
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3-Hydroxybenzylalkohol kann auf einfache und kostengünstige Weise hergestellt werden, wenn man (3-Chlormethylphenyl)-chlorformiat mit einer Carbons?ure und/oder einem Carbons?uresalz einer Acidolyse unterwirft und anschlie?end mit dem Reaktionsprodukt dieser ersten Stufe eine Alkoholyse durchführt.
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-
- Comparison of reactions of radical cations of 1-phenylalkanols produced by photoionization and by one-electron oxidation in aqueous solution
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Benzyl alcohols in aqueous solution react with photo- and radiation-chemically produced .OH and SO4.- radicals with diffusion-controlled rates to yield OH-adducts and benzyl alcohol radical cations, respectively. The former can be converted to the radical cations by H+-induced (heterolytic) dehydroxylation, whereas the latter decay by a) electrophilic reaction with water (= reverse of the dehydroxylation reaction) giving rise to Cnucleus-OH-adducts and by b) side chain C-H deprotonation yielding α-hydroxybenzyl-type radicals. If, however, the radical cation is produced by biphotonic ionization of the benzyl alcohol, the pattern of Cnucleus-OH bond formation and side chain C-H bond breakage is different from that in the reaction with SO4.-. It is concluded that, at least in this reaction, it is not the free, solvated radical cation that reacts with water but the ion pair [radical cation-SO42-].
- Steenken, Steen,Ramaraj, Ramasamy
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p. 1613 - 1619
(2007/10/03)
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- Magnesium-tin(II) chloride dihydrate: A new system for chemoselective reduction of aldehydes into alcohols in the presence of ketones, ketalization of ketones and dehalogenation of benzyl halides
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Magnesium-tin (II) chloride dihydrate in THF efficiently reduced aldehydes into their corresponding alcohols chemoselectively in the presence of ketones, formed ketals with ketones and glycol and dehalogenated benzyl halides.
- Bordoloi, Manobjyoti,Sharma, Ram P.,Chakraborty, Vaishali
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p. 2501 - 2506
(2007/10/03)
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