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Titania-supported molybdenum oxide combined with Au nanoparticles as a hydrogen-driven deoxydehydration catalyst of diol compounds
A heterogenous catalyst for the deoxydehydration (DODH) reaction was developed using less expensive Mo than Re as the active center. The combination of Mo with anatase-rich TiO2 and Au as the support and promoter for H2 activation, respectively, can selectively convert 1,4-anhydroerythritol to 2,5-dihydrofuran, which is a typical DODH model reaction, with H2 as a reducing agent. Loading of Au on TiO2 by the deposition-precipitation method gave the more active MoOx-Au/TiO2 catalyst (MoOx-dpAu/TiO2) than that obtained by the impregnation method (MoOx-impAu/TiO2), and the activity difference is derived from the smaller size of Au particles in MoOx-dpAu/TiO2 (3-5 nm) than that in MoOx-impAu/TiO2 (>25 nm). The MoOx-dpAu/TiO2 catalyst could be applied to the DODH reaction of linear alkyl vicinal diols and cis-1,2-cyclohexanediol. The characterization with XRD, STEM, H2-TPR, XAFS and XPS revealed that the MoIV oxide cluster species on the surface of anatase TiO2 particles are responsible for the DODH reaction.
Cao, Ji,Gan, Jianxing,Hacatrjan, Schanth,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi,Yabushita, Mizuho
p. 2146 - 2161
(2022/04/28)

Highly Selective Hydrodeoxygenation of Lignin to Naphthenes over Three-Dimensional Flower-like Ni2P Derived from Hydrotalcite
A strategy for low-temperature synthesis of hydrotalcite-based nickel phosphide catalysts (Ni2P-Al2O3) with flower-like porous structures was proposed. The in situ reduction of red phosphorus at 500 °C enables Ni2P catalysts with small particle size and abundant active and acidic sites, which facilitate the activation of substrates and H2. In the hydrodeoxygenation of guaiacol, a 100% conversion and 94.5% yield of cyclohexane were obtained over the Ni2P-Al2O3 catalyst under 5 MPa H2 at 250 °C for 3 h. Other lignin-derived phenolic compounds could also afford the corresponding alkanes with yields higher than 85%. Moreover, Ni2P-Al2O3 exhibited high hydrodeoxygenation activity in the deconstruction of more complex wood structures, including lignin oil and real lignin. Among the two different types of Ni sites of Ni(1) and Ni(2) in Ni2P, density functional theory (DFT) calculations showed that the Ni(2) site, highly exposed on the Ni2P-Al2O3 surface, possesses a stronger ability to break C-OH bonds during the hydrodeoxygenation of guaiacol in comparison with the Ni(1) site.
Chen, Guanyi,Diao, Xinyong,Ji, Na,Jia, Zhichao,Li, Changzhi,Li, Xinxin,Liu, Caixia,Liu, Qingling,Lu, Xuebin,Ma, Longlong,Song, Chunfeng,Wang, Shurong,Zhao, Yujun
p. 1338 - 1356
(2022/02/07)

Me3SI-promoted chemoselective deacetylation: a general and mild protocol
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
p. 19310 - 19315
(2021/06/03)

ATF6 MODULATORS AND USES THEREOF
Compounds (1-2) as modulators of Activating Transcription Factor 6 (ATF6) are provided. The compounds may find use as therapeutic agents for the treatment of diseases or disorders mediated by ATF6 and may find particular use in the treatment of viral infections, neurodegenerative diseases, vascular diseases, or cancer. (Formula (1-2))
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Paragraph 249

(2021/04/17)

The Effect of Sulfonate Groups in the Structure of Porous Aromatic Frameworks on the Activity of Platinum Catalysts Towards Hydrodeoxygenation of Biofuel Components
Abstract: Platinum catalysts based on porous aromatic frameworks (PAF-30 and PAF-30–SO3H) have been synthesized. Properties of the obtained catalysts have been assessed via hydrogenation of guaiacol, veratrole, and pyrocatechol at 250°С and hydrogen pressure 3.0 MPa in isopropanol medium. It has been shown that the presence of acidic sites in the catalyst significantly increases the yield of deoxygenation products. The effect of the substrate structure on the rate of its hydrodeoxygenation and the mechanism of the occurring processes have been studied. [Figure not available: see fulltext.]
Kalinina,Kulikov,Cherednichenko,Maximov,Karakhanov
p. 1061 - 1070
(2021/09/06)

Metal complex catalysts and method for catalytically reducing carboxylic acids
The invention relates to a metal complex catalyst, which contains at least one of metal complexes with a chemical formula comprising a structural unit represented by a formula I. According to the invention, the center metal of the metal complex catalyst is iridium, and the metal complex catalyst is composed of pentamethylcyclopentadienyl, a bitetrahydropyrimidine ligand and proper coordination anions; the metal complex catalyst has activity on a carboxylic acid reduction reaction, and a carboxylic acid compound is reduced into an alcohol compound in the presence of hydrogen; and the method ismild in reaction condition, can be carried out at room temperature, and is good in catalytic performance and high in reduction product yield.
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Paragraph 0156; 0163; 0164; 0178-0179

(2020/06/20)

Biocatalytic reduction of α,β-unsaturated carboxylic acids to allylic alcohols
We have developed robust in vivo and in vitro biocatalytic systems that enable reduction of α,β-unsaturated carboxylic acids to allylic alcohols and their saturated analogues. These compounds are prevalent scaffolds in many industrial chemicals and pharmaceuticals. A substrate profiling study of a carboxylic acid reductase (CAR) investigating unexplored substrate space, such as benzo-fused (hetero)aromatic carboxylic acids and α,β-unsaturated carboxylic acids, revealed broad substrate tolerance and provided information on the reactivity patterns of these substrates. E. coli cells expressing a heterologous CAR were employed as a multi-step hydrogenation catalyst to convert a variety of α,β-unsaturated carboxylic acids to the corresponding saturated primary alcohols, affording up to >99percent conversion. This was supported by the broad substrate scope of E. coli endogenous alcohol dehydrogenase (ADH), as well as the unexpected CC bond reducing activity of E. coli cells. In addition, a broad range of benzofused (hetero)aromatic carboxylic acids were converted to the corresponding primary alcohols by the recombinant E. coli cells. An alternative one-pot in vitro two-enzyme system, consisting of CAR and glucose dehydrogenase (GDH), demonstrates promiscuous carbonyl reductase activity of GDH towards a wide range of unsaturated aldehydes. Hence, coupling CAR with a GDH-driven NADP(H) recycling system provides access to a variety of (hetero)aromatic primary alcohols and allylic alcohols from the parent carboxylates, in up to >99percent conversion. To demonstrate the applicability of these systems in preparative synthesis, we performed 100 mg scale biotransformations for the preparation of indole-3-aldehyde and 3-(naphthalen-1-yl)propan-1-ol using the whole-cell system, and cinnamyl alcohol using the in vitro system, affording up to 85percent isolated yield.
Aleku, Godwin A.,Leys, David,Roberts, George W.
p. 3927 - 3939
(2020/07/09)

Production of oxygen-containing alicyclic compounds (by machine translation)
[Problem] to provide, in a one-step reaction synthesizes an alicyclic compound containing oxygen, high yield production of oxygen-containing compound is a cycloaliphatic. [Solution] one or more hydroxy or carbonyl group 2, or a hydroxyl group having the carbon number of 5 or more aliphatic carbonyl group 2 in accordance with one or more oxygen-containing compound, a basic catalyst is brought into contact with an oxygen-containing alicyclic compound by cyclodehydration reaction, oxygen-containing alicyclic compound. [Drawing] no (by machine translation)
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Paragraph 0027-0032; 0034

(2020/04/24)

Iridium-promoted conversion of terminal epoxides to primary alcohols under acidic conditions using hydrogen
A strategy for the conversion of terminal epoxides to primary alcohols is presented. The reaction uses hydrogen as the only stoichiometric reagent and is promoted by an iridium precatalyst under acidic conditions. Selectivity for the formation of a terminal alcohol over an internal alcohol is observed for both alkyl- and aryl-substituted terminal epoxides in isolated yields of up to 50% and 72% respectively.
Rainsberry, Alena N.,Sage, Jarrod G.,Scheuermann, Margaret L.
p. 3020 - 3022
(2019/06/27)

Acid-Promoted Hydroformylative Synthesis of Alcohol with Carbon Dioxide by Heterobimetallic Ruthenium-Cobalt Catalytic System
The acid-aided heterobimetallic ruthenium-cobalt catalytic system for the reductive hydroformylation with carbon dioxide was established. Various alkenes, including waste from biomass and petroleum industry, could be upgraded to valuable alcohols with this protocol. Acid-promoted reverse water-gas shift (RWGS), thereby accelerating the hydroformylative synthesis of alcohol. The theoretical computations revealed that acid promoted RWGS by facilitating the dehydroxylation of ruthenium hydroxy carbonyl intermediate.
Zhang, Xuehua,Tian, Xinxin,Shen, Chaoren,Xia, Chungu,He, Lin
p. 1986 - 1992
(2019/03/17)

Bridged bicyclic 2,3-dioxabicyclo[3.3.1]nonanes as antiplasmodial agents: Synthesis, structure-activity relationships and studies on their biomimetic reaction with Fe(II)
Despite recent advancements in its control, malaria is still a deadly parasitic disease killing millions of people each year. Progresses in combating the infection have been made by using the so-called artemisinin combination therapies (ACTs). Natural and synthetic peroxides are an important class of antimalarials. Here we describe a new series of peroxides synthesized through a new elaboration of the scaffold of bicyclic-fused/bridged synthetic endoperoxides previously developed by us. These peroxides are produced by a straightforward synthetic protocol and are characterized by submicromolar potency when tested against both chloroquine-sensitive and chloroquine-resistant Plasmodium falciparum strains. To investigate their mode of action, the biomimetic reaction of the representative compound 6w with Fe(II) was studied by EPR and the reaction products were characterized by NMR. Rationalization of the observed structure-activity relationship studies was performed by molecular docking. Taken together, our data robustly support the hypothesized mode of activation of peroxides 6a-cc and led to the definition of the key structural requirements responsible for the antiplasmodial potency. These data will pave the way in future to the rational design of novel optimized antimalarials suitable for in vivo investigation.
D'Alessandro, Sarah,Alfano, Gloria,Di Cerbo, Luisa,Brogi, Simone,Chemi, Giulia,Relitti, Nicola,Brindisi, Margherita,Lamponi, Stefania,Novellino, Ettore,Campiani, Giuseppe,Gemma, Sandra,Basilico, Nicoletta,Taramelli, Donatella,Baratto, Maria Camilla,Pogni, Rebecca,Butini, Stefania
supporting information

(2019/06/13)

Selective Hydrogenation of Carboxylic Acids to Alcohols or Alkanes Employing a Heterogeneous Catalyst
The chemoselective hydrogenation of carboxylic acids to either alcohols or alkanes is reported, employing a heterogeneous bimetallic catalyst consisting of rhenium and palladium supported on graphite. α-Chiral carboxylic acids were hydrogenated without loss of optical purity. The catalyst displays a reverse order of reactivity upon hydrogenation of different carboxylic functions with esters being less reactive than amides and carboxylic acids. This allows for chemoselective hydrogenation of an acid in the presence of an ester or an amide function.
Ullrich, Johannes,Breit, Bernhard
p. 785 - 789
(2018/02/14)

Robust cobalt oxide catalysts for controllable hydrogenation of carboxylic acids to alcohols
The selective catalytic hydrogenation of carboxylic acids is an important process for alcohol production, while efficient heterogeneous catalyst systems are still being explored. Here, we report the selective hydrogenation of carboxylic acids using earth-abundant cobalt oxides through a reaction-controlled catalysis process. The further reaction of the alcohols is completely hindered by the presence of carboxylic acids in the reaction system. The partial reduction of cobalt oxides by hydrogen at designated temperatures can dramatically enhance the catalytic activity of pristine samples. A wide range of carboxylic acids with a variety of functional groups can be converted to the corresponding alcohols at a yield level applicable to large-scale production. Cobalt monoxide was established as the preferred active phase for the selective hydrogenation of carboxylic acids.
Song, Song,Wang, Dong,Di, Lu,Wang, Chuanming,Dai, Weili,Wu, Guangjun,Guan, Naijia,Li, Landong
p. 250 - 257
(2018/02/20)

Hydrogen Sulfide: A Reagent for pH-Driven Bioinspired 1,2-Diol Mono-deoxygenation and Carbonyl Reduction in Water
Hydrogen sulfide (H2S) was evaluated for its peculiar sulfur radical species generated at different pHs and was used under photolytical conditions in aqueous medium for the reduction of 1,2-diols to alcohols. The conversion steps of 1,2-cyclopentanediol to cyclopentanol via cyclopentanone were analyzed, and it was proven that the reaction proceeds via a dual catalytic/radical chain mechanism. This approach was successfully adapted to the reduction of a variety of carbonyl compounds using H2S at pH 9 in water. This work opens up the field of environmental friendly synthetic processes using the pH-driven modulation of reactivity of this simple reagent in water.
Barata-Vallejo, Sebastián,Ferreri, Carla,Golding, Bernard T.,Chatgilialoglu, Chryssostomos
supporting information
p. 4290 - 4294
(2018/07/29)

Biocatalytic synthesis of chiral cyclic γ-oxoesters by sequential C-H hydroxylation, alcohol oxidation and alkene reduction
A three-step biocatalytic procedure is described for the conversion of methyl and ethyl cyclopentene- and cyclohexenecarboxylates into both the enantiomers of the corresponding chiral 3-oxoesters, which are useful building blocks for the synthesis of active pharmaceutical ingredients. The allylic hydroxylation of the starting cycloalkenecarboxylates is carried out by using R. oryzae resting cells entrapped in alginate beads, in acetate buffer solution at 25 °C. The oxidation of the intermediate allylic alcohols to unsaturated ketones, performed by the laccase/TEMPO system, and the ene-reductase mediated hydrogenation of the alkene bond were carried out in the same reaction vessel in a sequential mode at 30 °C. Being entirely biocatalytic, our multistep procedure provides considerable advantages in terms of selectivity and environmental impact over reported chemical methods.
Brenna, Elisabetta,Crotti, Michele,Gatti, Francesco G.,Monti, Daniela,Parmeggiani, Fabio,Pugliese, Andrea,Tentori, Francesca
supporting information
p. 5122 - 5130
(2017/11/09)

Hydrodeoxygenation of guaiacol on tungstated zirconia supported Ru catalysts
Ru nanoparticles supported on tungstated zirconia (WZr) were prepared and used for the catalytic hydrodeoxygenation of guaiacol to deoxygenated hydrocarbon fuels. The tuning of tungsten, from 5 to 20?wt%, adjusted the number of acid sites on the tungstated zirconia and the size of the Ru nanoparticles. The optimum fraction of tungsten was determined for the optimum hydrodeoxygenation activity. The conversion of guaiacol reached a maximum of 96.8% for 10?wt% of tungsten. Increasing the tungsten fraction increased the number of acid sites and the dispersion of Ru, but the formation of tungsten oxide (WOx) particles with too large fraction of tungsten inhibited the formation of smaller Ru nanoparticles, thus reducing the catalytic activity.
Dwiatmoko, Adid Adep,Kim, Inho,Zhou, Lipeng,Choi, Jae-Wook,Suh, Dong Jin,Jae, Jungho,Ha, Jeong-Myeong
p. 10 - 16
(2017/06/20)

One-Pot Process for Hydrodeoxygenation of Lignin to Alkanes Using Ru-Based Bimetallic and Bifunctional Catalysts Supported on Zeolite Y
The synthesis of high-efficiency and low-cost catalysts for hydrodeoxygenation (HDO) of waste lignin to advanced biofuels is crucial for enhancing current biorefinery processes. Inexpensive transition metals, including Fe, Ni, Cu, and Zn, were severally co-loaded with Ru on HY zeolite to form bimetallic and bifunctional catalysts. These catalysts were subsequently tested for HDO conversion of softwood lignin and several lignin model compounds. Results indicated that the inexpensive earth-abundant metals could modulate the hydrogenolysis activity of Ru and decrease the yield of low-molecular-weight gaseous products. Among these catalysts, Ru-Cu/HY showed the best HDO performance, affording the highest selectivity to hydrocarbon products. The improved catalytic performance of Ru-Cu/HY was probably a result of the following three factors: (1) high total and strong acid sites, (2) good dispersion of metal species and limited segregation, and (3) high adsorption capacity for polar fractions, including hydroxyl groups and ether bonds. Moreover, all bifunctional catalysts proved to be superior over the combination catalysts of Ru/Al2O3 and HY zeolite.
Wang, Hongliang,Ruan, Hao,Feng, Maoqi,Qin, Yuling,Job, Heather,Luo, Langli,Wang, Chongmin,Engelhard, Mark H.,Kuhn, Erik,Chen, Xiaowen,Tucker, Melvin P.,Yang, Bin
p. 1846 - 1856
(2017/04/27)

Mapping reactivities of aromatic models with a lignin disassembly catalyst. Steps toward controlling product selectivity
Copper-doped porous metal oxides catalyze the one-pot disassembly of biomass-derived lignin via C-O bond hydrogenolysis and hydrodeoxygenation in supercritical methanol. This catalytic system cleanly converts lignin as well as lignocellulose composites, such as sawdust, to organic liquids with little or no formation of intractable tars or chars. However, this catalyst based on Earth-abundant components also catalyzes less desirable aromatic ring hydrogenations and various methylations that contribute to the diversity of products. In this context, we undertook a quantitative experimental and computational evaluation of model reactions relevant to the reductive disassembly of lignin by this catalyst system in order to determine quantitatively the rates of desirable and less desirable chemical steps that define the overall product selectivities. Global fitting analysis methods were used to map the temporal evolution of key intermediates and products and to elucidate networks that provide guidelines regarding the eventual fates of reactive intermediates in this catalysis system. Phenolic compounds display multiple reaction pathways, but substrates such as benzene, toluene, and alkyl- and alkoxy-substituted aromatics are considerably more stable under these conditions. These results indicate that modifying this catalytic system in a way that controls and channels the reactivity of phenolic intermediates should improve selectivity toward producing valuable aromatic chemicals from biomass-derived lignin. To this end we demonstrate that the O-methylating agent dimethyl carbonate can intercept the phenol intermediate formed from hydrogenolysis of the model compound benzyl phenyl ether. Trapping the phenol as anisole thus gave much higher selectivity towards aromatic products.
Bernt, Christopher M.,Bottari, Giovanni,Barrett, Jacob A.,Scott, Susannah L.,Barta, Katalin,Ford, Peter C.
p. 2984 - 2994
(2016/05/24)

Water-Assisted Selective Hydrodeoxygenation of Lignin-Derived Guaiacol to Monooxygenates
Water, which frequently inhibits organic reactions, improves the hydrodeoxygenation activity of lignin-derived guaiacol on a bifunctional catalyst of Rh/SiO2-Al2O3 in a biphasic mixture of n-decane and water. The unique properties of subcritical water appear to promote hydrodeoxygenation, which improves the production of monooxygenates by removing more oxygen atoms of guaiacol while suppressing the formation of fully deoxygenated hydrocarbons because of the poor solubility of hydrophobic monooxygenates.
Yoon, Ji Sun,Choi, Jae-Wook,Suh, Dong Jin,Lee, Kangtaek,Lee, Hyunjoo,Ha, Jeong-Myeong
p. 2669 - 2674
(2015/09/15)

Synergistic effects of Ni and acid sites for hydrogenation and C-O bond cleavage of substituted phenols
The cleavage of C-O bonds in phenol, catechol, and guaiacol has been explored with mono- and dual-functional catalysts containing Ni and/or HZSM-5 in the aqueous phase. The aromatic ring of phenol is hydrogenated in the first step, and the C-O bond of the resulting cyclohexanol is dehydrated in sequence. The initial turnover frequency (TOF) of phenol hydrodeoxygenation increases in parallel with the acid site concentration irrespective of the concentration of the accessible surface Ni atoms. For catechol and guaiacol conversion, Ni catalyzes the hydrogenolysis of the C-O bonds in addition to arene hydrogenation. For catechol, the hydrogenation of the aromatic ring and the hydrogenolysis of the phenolic -OH group occur in parallel with a ratio of 8 : 1. The saturated cyclohexane-1,2-diol can be further dehydrated over HZSM-5 or hydrogenolyzed on Ni to complete hydrodeoxygenation. Guaiacol undergoes primarily hydrogenolysis (75%) to phenol via demethoxylation, and the hydrogenation route accounts for only 25%. This is attributed to the steric effects arising from the adjacent sp3 hybrid O-CH3 group. 2-Methoxycyclohexanol (from guaiacol hydrogenation) reacts further either via hydrogenolysis by Ni to cyclohexanol or via acid catalyzed demethoxylation and rearrangement steps followed by the subsequent hydrogenation of the intermediately formed olefins. On Ni/HZSM-5, the hydrodeoxygenation activities are much higher for the phenolic monomers than for their respective saturated analogues, pointing to the importance of sp2 orbitals. The presence of proximal acid sites increases the activities of Ni in the presence of H2 by a synergistic action. This journal is
Song, Wenji,Liu, Yuanshuai,Barth, Eszter,Zhao, Chen,Lercher, Johannes A.
p. 1204 - 1218
(2015/03/04)

Direct Ruthenium-Catalyzed Hydrogenation of Carboxylic Acids to Alcohols
The "green" reduction of carboxylic acids to alcohols is a challenging task in organic chemistry. Herein, we describe a general protocol for generation of alcohols by catalytic hydrogenation of carboxylic acids. Key to success is the use of a combination of Ru(acac)3, triphos and Lewis acids. The novel method showed broad substrate tolerance and a variety of aliphatic carboxylic acids including biomass-derived compounds can be smoothly reduced.
Cui, Xinjiang,Li, Yuehui,Topf, Christoph,Junge, Kathrin,Beller, Matthias
supporting information
p. 10596 - 10599
(2015/09/02)

Organoborane-Catalyzed Hydrogenation of Unactivated Aldehydes with a Hantzsch Ester as a Synthetic NAD(P)H Analogue
We have developed a method for the hydrogenation of unactivated aldehydes, using a Hantzsch ester as a NAD(P)H analogue in the presence of an electron-deficient triarylborane as a Lewis acid catalyst. Thus, tris[3,5-bis(trifluoromethyl)phenyl]borane efficiently catalyzes the hydrogenation of aliphatic aldehydes with a Hantzsch ester in 1,4-dioxane at 100 °C to give the corresponding aliphatic primary alcohols in up to 97% yield. Aromatic aldehydes also undergo the hydrogenation, even at 25 °C, to furnish the corresponding aromatic primary alcohols in up to 100% yield.
Hamasaka, Go,Tsuji, Hiroaki,Uozumi, Yasuhiro
supporting information
p. 2037 - 2041
(2015/09/01)

Hydrodeoxygenation of lignin model compounds over a copper chromite catalyst
The hydrodeoxygenation of benzyl alcohol, phenol, anisole, o-cresol, catechol, guaiacol, and vanillyl alcohol were carried out from 150 to 275 °C at 50 bar H2 with a CuCr2O4·CuO catalyst in a decalin solvent. The hydroxymethyl group of benzyl alcohol was found to be highly reactive towards hydrogenolysis to form toluene. Demethoxylation of anisole to form benzene was found to be the primary reaction pathway in contrast to demethylation and transalkylation reactions, which are more prevalent for conventional hydrotreating catalysts. The hydroxyl group of phenol strongly activated the aromatic ring towards hydrogenation forming cyclohexanol which was subsequently dehydrated and hydrogenated to form cyclohexane. Reaction networks of increasing complexity were devised for the major functional groups and integrated to describe the most complex molecule studied, vanillyl alcohol.
Deutsch, Keenan L.,Shanks, Brent H.
p. 144 - 150
(2013/03/13)

Preparation, characterization and use of 1,3-disulfonic acid imidazolium hydrogen sulfate as an efficient, halogen-free and reusable ionic liquid catalyst for the trimethylsilyl protection of hydroxyl groups and deprotection of the obtained trimethylsilanes
Novel 1,3-disulfonic acid imidazolium hydrogen sulfate, a halogen-free ionic liquid, is a recyclable and eco-benign catalyst for the trimethylsilyl protection of hydroxyl groups at room temperature under solvent free conditions to afford trimethylsilanes in excellent yields (92-100%) and in very short reaction times (1-5 min). Deprotection of the resulting trimethylsilanes can also be achieved using the same catalyst in methanol. The catalyst was characterized by IR, 1H NMR, 13C NMR and MS studies. All the products were extensively characterized by IR, 1H NMR, MS, and elemental and melting point analyses. This new method consistently has the advantages of excellent yields and short reaction times. Further, the catalyst can be recovered and reused for several times without loss of activity. The work-up of the reaction consists of a simple separation, followed by concentration of the crude product and purification.
Shirini, Farhad,Khaligh, Nader Ghaffari,Akbari-Dadamahaleh, Somayeh
p. 15 - 23
(2013/01/14)

Discrete iron complexes for the selective catalytic reduction of aromatic, aliphatic, and α,β-unsaturated aldehydes under water-gas shift conditions
Iron-catalyzed reductions: Selective iron-catalyzed reduction of aldehydes with hydrogen generated in situ by the water-gas shift reaction is presented (see scheme). The generality and selectivity of this mild procedure are demonstrated by the efficient reduction of various aromatic, aliphatic and α,β-unsaturated aldehydes.
Tlili, Anis,Schranck, Johannes,Neumann, Helfried,Beller, Matthias
p. 15935 - 15939
(2013/02/21)

Vapor-phase catalytic dehydration of terminal diols
Vapor-phase catalytic reactions of several terminal diols were investigated over several rare earth oxides, such as Sc2O3, Y 2O3, CeO2, Yb2O3, and Lu2O3. Sc2O3 showed selective catalytic activity in the dehydration of terminal diols with long carbon chain, such as 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol, to produce the corresponding unsaturated alcohols. In the dehydration of 1,6-hexanediol, 5-hexen-1-ol was produced with selectivity over 60 mol%, together with by-products such as ε-caprolactone and oxacycloheptane. In the dehydration of 1,10-decanediol, 9-decen-1-ol was produced with selectivity higher than 70 mol%. In addition to Sc 2O3, heavy rare earth oxides such as Lu2O 3 as well as monoclinic ZrO2 showed moderate selectivity in the dehydration of the terminal diols.
Abe, Katsutoshi,Ohishi, Yusuke,Okada, Takuto,Yamada, Yasuhiro,Sato, Satoshi
experimental part
p. 419 - 424
(2012/02/03)

Reduction of carboxylic acids using esters of benzotriazole as high-reactivity intermediates
Herein, we describe a simple and practical protocol for the reduction of carboxylic acids via the in situ formation of hydroxybenzotriazole esters followed by reaction with sodium borohydride to give the corresponding alcohols. The reaction proceeds with excellent yields in the presence of water. Georg Thieme Verlag Stuttgart - New York.
Morales-Serna, Jose Antonio,Garcia-Rios, Erendira,Bernal, Jorge,Paleo, Ehecatl,Gavino, Ruben,Cardenas, Jorge
scheme or table
p. 1375 - 1382
(2011/06/19)

Impregnated palladium on magnetite as catalyst for multicomponent reductive amination reactions and other related reducing processes
The impregnated palladium on magnetite catalyst is a versatile system for different reduction processes using inexpensive polymehtylhydrosiloxane, including multicomponent reductive amination reactions, and aldehyde, imine, sulfinimide and sulfoxide reductions. This catalyst avoids the use of any type of expensive and quite expensive organic ligand, showing excellent yields, under mild reaction conditions. The catalyst is easily removed from the reaction medium, just by using a magnet. The catalytic system is very selective permitting the discrimination between ketones and aldehydes in the reductive amination process.
Cano, Rafael,Yus, Miguel,Ramón, Diego J.
experimental part
p. 8079 - 8085
(2011/11/04)

A simple and selective method for the O-AcCl removal using sodium borohydride
A deprotection of chloroacetylated alcohols using NaBH4 is reported. The free alcohols are obtained in excellent yields. The reaction was performed on primary, secondary, alkyl, allyl, benzylic alcohols and phenols. The compatibility of the method with other sensitive or protective groups is demonstrated.
Villedieu, Emmanuelle,Lopin-Bon, Chrystel,Berteina-Raboin, Sabine
scheme or table
p. 2115 - 2118
(2010/06/14)

Investigation of cyclization reactions of dicyclohexyl-6-iodo- and -6-tosylhexenylborane. A facile radical cyclization diverted to a rearrangement-cyclization with base
(Chemical Equation Presented) Dicyclohexyl-6-iodohexenylborane efficiently undergoes radical cyclization at room temperature using tri-n-butyltin hydride as a hydrogen donor and without the aide of a radical initiator. Efforts to develop environmentally f
Hinkens, Diane M.,Midland, M. Mark
experimental part
p. 4143 - 4148
(2009/09/25)

Alkyl radical generation in water under ambient conditions - A new look at the Guareschi reaction of 1897
(Chemical Equation Presented) Chemical and biochemical significance of a long-forgotten 19th century observation: The hydrocarbon production from quaternary glutarimides on neutralization in water is the consequence of formation of alkyl radicals, which means that it is possible to generate alkyl radicals under very mild conditions. Oxygen trapping competes with hydrogen abstraction (see scheme).
Nguyen, Bao,Chernous, Katya,Endlar, Daniel,Odell, Barbara,Piacenti, Michela,Brown, John M.,Dorofeev, Alexander S.,Burasov, Alexander V.
p. 7655 - 7658
(2008/09/18)

SIGMA RECEPTOR BINDER CONTAINING INDANONE DERIVATIVE
The present invention provides an indanone derivative and an excellent sigma receptor binding agent comprising an indanone derivative. More specifically, it provides a sigma receptor binding agent comprising an indanone derivative represented by the following formula, a pharmacologically acceptable salt thereof or a hydrate of them. In the formula (I), R1, R2, R3 and R4 are the same as or different from each other and each represents hydrogen atom, a halogen atom, hydroxyl group, nitrile group, a C1-6 alkyl group which may be substituted, a cycloalkyl group having three to eight carbon atoms which may be substituted, a C1-6 alkoxy group which may be substituted, a cycloalkoxy group having three to eight carbon atoms which may be substituted, an acyl group having one to six carbon atoms which may be substituted, a C1-6 alkoxycarbonyl group which may be substituted, a C1-6 alkylaminocarbonyloxy group which may be substituted, a di(C1-6 alkyl)aminocarbonyloxy group which may be substituted, nitro group, an amino group which may be substituted, an amido group which may be substituted, mercapto group or a thio-C1-6 alkoxy group which may be substituted, and further R1 with R2, R2 with R3, or R3 with R4 may together form an aliphatic ring, an aromatic ring, a heterocyclic ring or an alkylenedioxy ring; the partial structure: represents a group represented by >CH-CH2-, >C=CH- or >C(-R7)-CH2-; m represents an integer of 0 or 1 to 5; and R5 represents hydrogen atom, a C1-6 alkyl group which may be substituted, a C2-6 alkenyl group which may be substituted, a C2-6 alkynyl group which may be substituted, a cycloalkyl group having three to eight carbon atoms which may be substituted, a 2,2-(alkylenedioxy)ethyl group or a group represented by the formula: (wherein the ring C represents benzene ring, an aliphatic ring or a heterocyclic ring; R6s are the same as or different from each other and each represents hydrogen atom, a halogen atom, hydroxyl group, nitrile group, a C1-6 alkyl group which may be substituted, a C2-6 alkenyl group which may be substituted, a C2-6 alkynyl group which may be substituted, a cycloalkyl group having three to eight carbon atoms which may be substituted, a C1-6 alkoxy group which may be substituted, a C1-6 alkoxyalkoxy group which may be substituted, an aryloxy group which may be substituted or an aralkyloxy group which may be substituted, and further two of R6s may together form an aliphatic ring, an aromatic ring, a heterocyclic ring or an alkylenedioxy ring; R7 represents a halogen atom, hydroxyl group, a C1-6 alkyl group which may be substituted, a C1-6 alkoxy group, nitrile group, a halogeno-C1-6 alkyl group, a hydroxyl-C1-6 alkyl group, a cyano-C1-6 alkyl group, an amino-C1-6 alkyl group, nitro group, azide group, an amino group which may be substituted, a carbamoyl group which may be substituted, a carboxyl group which may be substituted, mercapto group or a thio-C1-6 alkoxy group; and n represents an integer of 1 to 5), provided that 1-benzyl-4-[(5,6-dimethoxy-1-indanon)-2-yl]methylpiperidine, a pharmacologically acceptable salt thereof or a hydrate of them are excluded.
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Page 18

(2008/06/13)

Method for producing 1,6-hexanediol
A process for producing 1,6-hexanediol by hydrogenation of adipic esters and/or 6-hydroxycaproic esters in the gas phase at elevated temperature and elevated pressure in the presence of chromium-free catalysts comprises hydrogenating a) over a catalyst comprising copper, manganese and aluminum as essential constituents or over Raney copper, b) at a temperature of from 150 to 230° C. and a pressure of from 10 to 70 bar, c) at a molar ratio of hydrogen to ester to be hydrogenated within the range from 150:1 to 300:1, and d) at a catalyst space velocity of from 0.01 to 0.3 kg of C6ester per liter of catalyst per hour.
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Page column 6

(2008/06/13)

Organolanthanide-Catalyzed Cyclization/Boration of 1,5- and 1,6-Dienes
(Matrix Presented) 1,5- and 1,6-Dienes undergo a cyclization/boration reaction in the presence of a catalytic amount of Cp*2Sm·THF. The resulting organoboranes can be oxidized to the corresponding primary cyclic alcohols using standard conditions.
Molander, Gary A.,Pfeiffer, Dirk
p. 361 - 363
(2007/10/03)

A novel hydrogen transfer hydroalumination of alkenes with triisobutylaluminum catalyzed by Pd and other late transition metal complexes
Hydrogen transfer hydroalumination of terminal alkenes and dienes can be achieved with 1.1 equiv. of (i-Bu)3Al and catalytic amounts of Cl2Pd(PPh3)2 and other late transition metal complexes containing Co, Rh, Ni, and Pt at ambient temperature in high yields.
Gagneur, Sebastien,Makabe, Hidefumi,Negishi, Ei-Ichi
p. 785 - 787
(2007/10/03)

Tetraphenyldistibine: A Most Useful Reagent for Discriminating Radical Reactions
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Barrett, Anthony G.M.,Melcher, Laura M.
p. 8177 - 8178
(2007/10/02)

Catalytic procedure for the synthesis of cycloalkanemethanols from cycloalkenes and aqueous methyl formate
Cycloalkanemethanols are synthesized via hydrocarbonylation (hydroformylation) of the corresponding cycloalkenes in the presence of aqueous methyl formate. Methyl formate is the source of carbon monoxide and hydrogen is generated by the water gas shift reaction. The selectivity is affected by the concomitant hydrogenation process.
Jenner
p. 505 - 508
(2007/10/02)

A kinetic study of the alkaline hydrolysis of four-coordinated phosphorus (PIV) compounds. Impact of conformational transmission in the transiently formed five-coordinated (PV-TBP) intermediates on reaction rate and product distribution
It can be shown that alkaline hydrolysis of four-coordinated phosphorus (PIV) compounds is substantially accelerated if the trigonal-bipyrimidal (TBP) five-coordinated phosphorus (PV) intermediate in the reaction can exhibit conformational transmission.With the compounds 5a-c, it was shown that this acceleration is an entropy effect.Pseudorotation in the PV-TBP intermediate is facilitated if conformational transmission occurs, and therefore the entropy loss during build-up of the PV-TBP is reduced.This evidently results in a lower free energy of activation for the reaction.For the phosphate triester systems 6a and 6b , it was also found that the occurence of conformational transmission speeds up the hydrolysis reaction, although the effect is less pronounced than for the compounds 5a-c.The cyclopentylmethoxy group (6a) and the tetrahydrofurfuryloxy group (6b) show slight preferences for equatorial and axial positioning in the transient PV-TBP, respectively.This study shows for the first time that reaction rate and product selectivity of hydrolyses of phosphate esters can be determined in part by the conformational transmission effect.
Koole, Leo H.,Olders, Edith A. T. A.,Opresnik, Marko,Buck, Henk M.
p. 55 - 58
(2007/10/02)

NEW ORGANOCOPPER REAGENTS PREPARED UTILIZING HIGHLY REACTIVE COPPER
Highly reactive copper solutions have been prepared by the lithium naphthalide reduction of copper(I) iodide/trialkylphosphine complexes.These activated copper solutions will react with organic halides under very mild conditions to form stable organocopper reagents.Significantly, the organocopper reagents can contain considerable functionalities such as ester, nitrile, chloride, epoxide, and ketone groups.These functionalized organocopper species undergo many reactions typical of other organocopper species.Intermolecular 1,4-additions, epoxide-opening reactions, and ketone formation with acid chlorides have been successfully achieved.In addition, this methodology has been applied to an intramolecular epoxide-cleavage reaction.The influence of the connecting chain length, substitution pattern, reaction solvent, and CuI/phosphine complex upon the regioselectivity of the intramolecular cyclization is described.
Rieke, Reuben D.,Wehmeyer, Richard M.,Wu, Tse-Chong,Ebert, Greg W.
p. 443 - 454
(2007/10/02)

Rate Enhancement of Nucleophilic Substitution Reactions in Phosphate Esters. Influence of Conformational Transmission on the Rate of Solvolysis of Alkyl Diphenylphosphinates
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Keijzer, A. E. H. de,Koole, L. H.,Hofstad, W. J. M. van der,Buck, H. M.
p. 1453 - 1456
(2007/10/02)

DIRECT FORMATION OF EPOXYALKYLCOPPER REAGENTS FROM ACTIVATED COPPER AND EPOXYALKYL BROMIDES AND THEIR INTRAMOLECULAR CYCLIZATIONS
Epoxyalkylcopper compounds have readily been prepared by the direct oxidative addition of active copper to epoxyalkyl halides.The intramolecular cyclization of the epoxyalkylcopper reagents via an epoxide cleavage process is described.Significantly, many functional groups can be present in the bromoepoxides yielding highly functionalized carbocycles.The regioselectivity of this cyclizations is affected by the connecting chain length, substitution pattern, reaction solvent, and the CuI-phosphine complex used to generate the copper.
Wu, Tse-Chong,Rieke, Reuben D.
p. 6753 - 6756
(2007/10/02)

FUNCTIONALISATION OF SATURATED HYDROCARBONS. Part X. A COMPARATIVE STUDY OF CHEMICAL AND ELECTROCHEMICAL PROCESSES (GIF AND GIF-ORSAY SYSTEMS) IN PYRIDINE, IN ACETONE AND IN PYRIDINE-CO-SOLVENT MIXTURES
Six saturated hydrocarbons (cyclohexane, 3-ethylpentane, methylcyclopentane, cis- and trans-decalin and adamantane) were oxidised by the Gif system (iron catalyst, oxygen, zinc, carboxylic acid) and its electrochemical equivalent (Gif-Orsay system).Results obtained using various solvents (pyridine, acetone, pyridine-acetone mixtures) were similar for both systems.Total or partial replacement of pyridine with acetone affects the selectivity for secondary positions and lowers the ketone/secondary alcohol ratio.The formation of the same ratio of cis- and trans-decal-9-ol from both cis- and trans-decalin clearly demonstrates that tertiary alcohols result from a mechanism essentially radical in nature.
Belavoine, Gilbert,Barton, Derek H. R.,Boivin, Jean,Gref, Aurore,Coupanec, Pascale Le,et al.
p. 1091 - 1106
(2007/10/02)

Rate constant for chlorine abstraction from CCl4 by the 5-hexenyl radical
Cyclization of the 5-hexenyl free radical to the cyclopentylmethyl free radical was used to clock chlorine atom abstraction by 5-hexenyl from carbon tetrachloride in solution.The source of 5-hexenyl radicals was 5-hexenyldiazene((CH3)2C(OH)N=N(CH2)4CH=CH2), which decomposes thermally in CCl4 by a radical chain mechanism to afford chloroform, acetone, nitrogen, 6-chloro-1-hexene, cyclopentylchloromethane, 1-hexene, and methylcyclopentane as primary products. 6-Chloro-1-hexene is converted, in part, to a secondary product, 1,1,1,3,7-pentachloroheptane, by radical chain addition of CCl4 to the double bond.The rate constant for chlorine atom abstraction, kCl, was calculated from the product composition and the known rate constant for cyclization of the 5-hexenyl radical.For the temperature range 274-353 K, kCl is given by log(kCl/M-1s-1) = (8.4 +/- 0.3) - (6.2 +/- 0.4)/Τ where Τ = 2.3 RT kcal mol-1, which leads to kCl25 deg C = 7.2E3 M-1s-1.This value is significantly smaller than recently reported estimates for other primary alkyl radicals.
Jewell, Deborah Rae,Mathew, Lukose,Warkentin, John
p. 311 - 315
(2007/10/02)

RATE CONSTANT FOR HYDROXYLATION OF A PRIMARY ALKYL RADICAL BY INDUCED DECOMPOSITION OF AN ALPHA HYDROPEROXYALKYL DIAZENE
Rate constants for induced decomposition of 5-hexenyl(1-hydroperoxy-1-methylethyl)diazene ((CH3)2C(OOH)N=N(CH2)4CH=CH2, 2) have been estimated.Thermolysis of 2 at 50 deg C affords 5-hexenyl radicals which abstract the hydroxyl group from 2 in competition with cyclization of 5-hexenyl to cyclopentylmethyl radicals.The known rate constant (kc) for that cyclization was used to clock the bimolecular hydroxyl abstraction process.For reaction in hexafluorobenzene at 50 deg C, the rate constant for abstraction of hydroxyl from 2 (kOH) was found to be dependent on the concentration of 2.For example, at = 0.4M, kOH = 3.2*106 M-1s-1 whereas, at = 0.10 M, kOH = 1.8*107 M-1s-1.The concentration dependence of kOH is attributed to the effects of intermolecular hydrogen bonding and the large absolute values of kOH are ascribed to concerted induced decomposition, the O - O bond being broken in concert with scission of the nearest C - N bond of the azo function.The relevance of the results, to synthetic application of α-hydroperoxyalkyl diazenes in hydroxyalkylation reactions, is discussed.
Lakhani, Chandra,Mathew, Lukose,Warkentin, John
p. 1748 - 1752
(2007/10/02)

REGIOSELECTIVE HYDROALUMINATION OF UNSATURATED HYDROCARBONS BY ALKYLALANES CATALYZED BY ZIRCONIUM COMPLEXES
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Dzhemilev, U. M.,Ibragimov, A. G.,Vostrikova, O. S.,Vasil'eva, E. V.,Tolstikov, G. A.
p. 1004 - 1009
(2007/10/02)

Proton, Carbon, and Phosphorus Nuclear Magnetic Resonance and Conformational Studies on Phosphate Esters
The conformational free energies of phosphate and phosphoryloxymethyl groups on a cyclohexane ring were 0.94 and 0.88 kcal mol-1 in deuterium oxide at pD 5 and 0.20 and 1.09 kcal mol-1 in dimethyl sulphoxide, respectively.For the rotational isomerism of the C-O axis of phosphate esters, 3JPH coupling constants indicate that the conformers with a planar trans arrangement of P-O and C(1)-CH2 bonds on primary phosphates or of P-O and C(1)-C(2 or 6) bonds on secondary phosphates predominated.The carbon magnetic shieldings in the vicinity of the phosphate ester function are interpreted in terms of an electronic exchange process.
Sugiyama, Hiroshi,Senda, Yasuhisa,Ishiyama, Jun-ichi
p. 391 - 396
(2007/10/02)

Radical Chain Mechanism for Alkyl Rearrangement in Organocobalt Complexes
The molecular rearrangement of a series of 5-hexenylcobalt(III) complexes of various Schiff bases is demonstrated to proceed via an unusual radical chain process.Thus the facility with the 5-hexenyl --> cyclopentylmethyl rearrangement occurs is highly dependent on the presence of trace impurities which can vary from the age of a highly purified sample to the presence of air.We find that the rearrangement of (5-hexenyl)CoIII(salen) I can be deliberately controlled by inhibiting it completely or by promoting it rapidly.For example, the addition of cobalt(II), nitroxide (TEMPO), dioxygen, or dihydroanthracene as well as an electrochemical preduction procedure can effectively squelch the 5-hexenyl rearrangement.Conversely, chemical and electrochemical oxidations with a ferrocenium salt and a platinium anode at 0.4 V, respectively, trigger the rearrangement.In each case, the limited molar amounts of additives (or faradays of charge) are sufficiently small to ensure high kinetic chain lenghts.Inhibition and initiation of the chain process by these techniques relate directly to the destruction and generation, respectively, of alkyl radicals as the prime reactive intermediates.Accordingly, a homolytic displacement (SH2) of the alkylcobalt(III) complex is proposed, in conjuction with the well-known rearrangement of the hexenyl radical, to constitute the two-step propagation cycle in Scheme III.Such a mechanism accounts for the intermolecular character of the hexenyl rearrangement as established by crossover experiments and the observation of a concurrent alkyl exchange which would otherwise be difficult to explain.The spontaneous rearrangement of a freshly prepared sample of (hexenyl)CoIII(salen) and the dichotomous effect of pyridine as a donor ligand are both readily accommodated within the content of the mechanism in Scheme III.
Samsel, E. G.,Kochi, J. K.
p. 4790 - 4804
(2007/10/02)

Steroids
Novel 9α,11β-dichloro-16α-methyl-Δ1,4 -pregnadiene 3,20-diones of the formula STR1 wherein R is selected from the group consisting of trimethylsilylphenyl, cyclododecyloxy, dicyclopentylmethoxy and cyclohexylmethoxy having a suprising "in loco" anti-inflammatory activity limited to place of inflammation without systemic effects and a process for their preparation.
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(2008/06/13)

REGIOCHEMISTRY OF THE METAL-HALOGEN EXCHANGE INDUCED CYCLIZATION OF ω-IODOEPOXIDES
The regiochemistry of the cyclization reactions of some ω-lithioepoxides as a function of chain length and substitution pattern has been examined.Striking changes in regiochemistry have been observed in the presence of certain Lewis acids and metal halides.
Cooke, Manning P.,Houpis, Ioannis N.
p. 3643 - 3646
(2007/10/02)

CYCLIZATION OF 6-BROMO-1,2-EPOXYHEXANE PROMOTED BY METAL-HALOGEN EXCHANGE: UNEXPECTED REGIOSELECTIVITY
Treatment of 6-bromo-l,2-epoxyhexane (1) with one equivalent of sec-butyllithium afforded a 95:5 mixture of cyclopentylmethanol (4): cyclohexanol in approximately 40percent yield.An analogous tandem metal-halogen exchange/cycloalkylation process using the oxirane derivative (2) of 6-iodo-1-hexene gave virtually the same mixture of alcohols in >60percent yield.
Babler, James H.,Bauta, William E.
p. 4323 - 4324
(2007/10/02)