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Synthesis and Applications of (Pyridyl)imine Fe(II) Complexes as Catalysts in Transfer Hydrogenation of Ketones
Abstract: Chiral (pyridyl)imine Fe(II) complexes, [Fe(L1)3]2+[PF6?]2, (Fe1), [Fe(L2)3]2+[PF6?]2, (Fe2), [Fe(L3)3]2+[PF6?]2 (Fe3), and [Fe(L4)3]2+[PF6?]2 (Fe4) were synthesised by reactions of synthons (S-)-1-phenyl-N-(pyridine-2-yl) ethylidine)ethanamine (L1), (R-)-1-phenyl-N-(pyridine-2-yl) ethylidine) ethanamine (L2), (S)-1-phenyl-N-(pyridine-2-yl methylene) ethanamine (L3) and (S)-1-phenyl-N-(pyridine-2-yl methylene)ethanamine (L4) with the FeCl2 salt. The solid-state structure of complex Fe4 showed that the?Fe atom contains three units of bidentate bound ligand L4 to form a six-coordinate cationic compound. The Fe(II) complexes were evaluated as catalysts in asymmetric transfer hydrogenation of ketones reactions and showed moderate catalytic activities with low enantioselectivity. Catalytic activities of the respective complexes were regulated by the nature of the metal complexes, ketone substrate and reaction conditions. Mercury and sub-stoichiometric poisoning experiments implicate possible formation of both active Fe(0) nanoparticles and Fe(II) homogeneous intermediates. Graphic Abstract: [Figure not available: see fulltext.]
Kumah, Robert T.,Vijayan, Paranthaman,Ojwach, Stephen O.
p. 344 - 352
(2020/07/25)

Method for preparing beta-diol from beta-diketone
The invention relates to a method for preparing beta-diol from beta-diketone. The method is characterized in that beta-diketone contacts and reacts with hydrogen in the presence of a hydrogenation catalyst under fixed bed reaction conditions, the hydrogenation catalyst comprises an active component copper and a carrier, and the hydrogenation catalyst preferably comprises an assistant component selected from VIIIB and IB group elements, the assistant is preferably selected from one or more of Ni, Co and Ag, and the carrier is SiO2. The method adopting a fixed bed hydrogenation technology and using a copper-containing supported catalyst has the advantages of no pollution to environment, mild operating conditions, and suitableness for continuous production.
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Paragraph 0037; 0048; 0049

(2016/11/24)

Method for preparing beta-diol from beta-diketone by hydrogenation
The invention relates to a method for preparing beta-diol from beta-diketone by hydrogenation. The method comprises the following steps: in the presence of a catalyst and under the fixed-bed hydrotreating reaction condition, enabling beta-diketone to be in contact with hydrogen, so as to obtain beta-diol, wherein the catalyst contains CuO and ZnO, preferably also contains Al2O3, and more preferably also contains alkali metal oxides. According to the method for preparing beta-diol from beta-diketone by hydrogenation, provided by the invention, the technology of continuously producing beta-diol by adopting a fixed bed device is realized, the technology is simple and convenient to operate, the utilization ratio of raw materials and the production efficiency of products are improved, the reaction does not need to be carried out under high pressure, and potential safety hazards are reduced.
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Paragraph 0041-0044

(2017/02/23)

A β-diketone fixed bed hydrogenation method for preparing β-diol (by machine translation)
The invention relates to a β-diketone fixed bed hydrogenation method for preparing β-diol, including in the presence of hydrogenation catalyst under conditions and fixed bed reaction of the β-diketone reaction contact with hydrogen gas; the hydrogenation catalyst comprises active component copper and carrier, wherein in order to weight part, the content of copper is 20-35 parts, carrier is in a content of 60-80 parts. Preferably, the hydrogenation catalyst also includes selected from group IB and VIIIB additive component, more preferably the assistant is selected from Ni, Ag Co and in one or several of, the carrier is SiO 2. The method provided by the present invention which adopts a fixed bed hydrogenation process and the use of copper-containing supported catalyst, no pollution to the environment, mild operating conditions, is suitable for continuous production. (by machine translation)
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Paragraph 0038-0039

(2017/02/28)

Method for preparation of beta-diol
The present invention relates to a method for preparation of a beta-diol from a beta-diketone by hydrogenation, the method comprises contact reaction of the beta-diketone and hydrogen in the presence of a hydrogenation catalyst and under fixed bed reaction conditions, the hydrogenation catalyst is a non-noble metal catalyst, includes a metal component and a carrier, and can be prepared by a conventional method. The method uses a fixed bed hydrogenation process, and is free of environmental pollution, mild in operating conditions, and suitable for continuous production.
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Paragraph 0030-0031

(2017/03/17)

Rabbit 3-hydroxyhexobarbital dehydrogenase is a NADPH-preferring reductase with broad substrate specificity for ketosteroids, prostaglandin D2, and other endogenous and xenobiotic carbonyl compounds
3-Hydroxyhexobarbital dehydrogenase (3HBD) catalyzes NAD(P) +-linked oxidation of 3-hydroxyhexobarbital into 3-oxohexobarbital. The enzyme has been thought to act as a dehydrogenase for xenobiotic alcohols and some hydroxysteroids, but its physiological function remains unknown. We have purified rabbit 3HBD, isolated its cDNA, and examined its specificity for coenzymes and substrates, reaction directionality and tissue distribution. 3HBD is a member (AKR1C29) of the aldo-keto reductase (AKR) superfamily, and exhibited high preference for NADP(H) over NAD(H) at a physiological pH of 7.4. In the NADPH-linked reduction, 3HBD showed broad substrate specificity for a variety of quinones, ketones and aldehydes, including 3-, 17- and 20-ketosteroids and prostaglandin D2, which were converted to 3α-, 17β- and 20α-hydroxysteroids and 9α,11β- prostaglandin F2, respectively. Especially, α-diketones (such as isatin and diacetyl) and lipid peroxidation-derived aldehydes (such as 4-oxo- and 4-hydroxy-2-nonenals) were excellent substrates showing low Km values (0.1-5.9 μM). In 3HBD-overexpressed cells, 3-oxohexobarbital and 5β-androstan-3α-ol-17-one were metabolized into 3-hydroxyhexobarbital and 5β-androstane-3α,17β-diol, respectively, but the reverse reactions did not proceed. The overexpression of the enzyme in the cells decreased the cytotoxicity of 4-oxo-2-nonenal. The mRNA for 3HBD was ubiquitously expressed in rabbit tissues. The results suggest that 3HBD is an NADPH-preferring reductase, and plays roles in the metabolisms of steroids, prostaglandin D2, carbohydrates and xenobiotics, as well as a defense system, protecting against reactive carbonyl compounds.
Endo, Satoshi,Matsunaga, Toshiyuki,Matsumoto, Atsuko,Arai, Yuki,Ohno, Satoshi,El-Kabbani, Ossama,Tajima, Kazuo,Bunai, Yasuo,Yamano, Shigeru,Hara, Akira,Kitade, Yukio
p. 1366 - 1375
(2013/11/19)

An efficient one-step chemoselective reduction of alkyl ketones over aryl ketones in β-diketones using LiHMDS and lithium aluminium hydride
β-Hydroxy ketones were synthesized in one-pot from β-diketones by reducing alkyl ketones chemoselectively by keeping aryl ketone intact. Initially, β-diketones were enolized using LiHMDS and later alkyl ketone was chemoselectively reduced efficiently by lithium aluminium hydride. This method produces β- hydroxyl ketones from the corresponding β-diketones in high yield.
Veeraswamy,Indrasena Reddy,Venkat Ragavan,Tirumal Reddy,Yennam, Satyanarayana,Jayashree
experimental part
p. 4651 - 4653
(2012/09/05)

Albumin-directed stereoselective reduction of 1,3-diketones and β-hydroxyketones to anti diols
The reduction of 1,3-diketones and β-hydroxyketones with NaBH 4 in aqueous acetonitrile is highly stereoselective in the presence of stoichiometric amounts of bovine or human albumin, giving anti 1,3-diols with d.e. up to 96%. The same reaction, without albumin, gives syn and anti 1,3-diols in approximately 1:1 ratio. The presence of an aromatic carbonyl group is essential for diastereoselectivity in the NaBH4/albumin reduction of both 1,3-diketones and β-hydroxyketones. Thus, 3-hydroxy-1-(p-tolyl)-1- butanone is stereoselectively reduced in the presence of albumin, while reduction of its isomer 4-(p-tolyl)-4-hydroxy-2-butanone is not stereoselective. The albumin-controlled reduction is not stereospecific as both enantiomers of 1-aryl-3-hydroxy-1-butanones are reduced to diols with identical stereoselectivities. Circular dichroism of the bound substrates confirms that aromatic ketones are recognized by the protein's IIA binding site. Binding studies also suggest that 1,3-diketones are recognized in their enol form. From the effect of pH on binding of a diketone it is concluded that, in the complex with the substrate, ionizable residues His242 and Lys199 are in the neutral and protonated forms, respectively. A homology model of BSA was obtained and docking of model substrates confirms the preference of the protein for aromatic ketones. Modelling of the complexes with the substrates also allows us to propose a mechanism for the reduction of 1,3-diketones in which the chemoselective reduction of the first (aliphatic) carbonyl is followed by the diastereoselective reduction of the second (aromatic) carbonyl. The role of albumin is thus a combination of chemo- and stereocontrol.
Berti, Federico,Bincoletto, Simone,Donati, Ivan,Fontanive, Giampaolo,Fregonese, Massimo,Benedetti, Fabio
experimental part
p. 1987 - 1999
(2011/04/25)

Highly efficient and stereoselective biosynthesis of (2S,5S)-hexanediol with a dehydrogenase from Saccharomyces cerevisiae
The enantiopure (2S,5S)-hexanediol serves as a versatile building block for the production of various fine chemicals and pharmaceuticals. For industrial and commercial scale, the diol is currently obtained through bakers' yeast-mediated reduction of 2,5-hexanedione. However, this process suffers from its insufficient space-time yield of about 4 g L-1 d-1 (2S,5S)-hexanediol. Thus, a new synthesis route is required that allows for higher volumetric productivity. For this reason, the enzyme which is responsible for 2,5-hexanedione reduction in bakers' yeast was identified after purification to homogeneity and subsequent MALDI-TOF mass spectroscopy analysis. As a result, the dehydrogenase Gre2p was shown to be responsible for the majority of the diketone reduction, by comparison to a Gre2p deletion strain lacking activity towards 2,5-hexanedione. Bioreduction using the recombinant enzyme afforded the (2S,5S)-hexanediol with >99% conversion yield and in >99.9% de and ee. Moreover, the diol was obtained with an unsurpassed high volumetric productivity of 70 g L-1 d-1 (2S,5S)-hexanediol. Michaelis-Menten kinetic studies have shown that Gre2p is capable of catalysing both the reduction of 2,5-hexanedione as well as the oxidation of (2S,5S)-hexanediol, but the catalytic efficiency of the reduction is three times higher. Furthermore, the enzyme's ability to reduce other keto-compounds, including further diketones, was studied, revealing that the application can be extended to α-diketones and aldehydes.
Mueller, Marion,Katzberg, Michael,Bertau, Martin,Hummel, Werner
experimental part
p. 1540 - 1550
(2010/07/04)

Heterogenized Ru(II) phenanthroline complex for chemoselective hydrogenation of diketones under biphasic aqueous medium
The chemoselective hydrogenation of acetylacetone to 4-hydroxypentan-2-one over immobilized ruthenium phenanthroline metal complexes in amino functionalized MCM-41 in biphasic aqueous reaction medium was investigated. The catalyst was characterized by XRD, TEM, surface analysis, FT-IR and UV-vis to understand the morphology, complex geometry, and XPS such that the oxidation state of the metal complex inside the MCM-41 framework could be understood. The use of water as a solvent, not only gives high activity and selectivity for hydrogenation of acetylacetone, but also gives a path for an environmentally safer process. The optimizations of ligand, metal to ligand ratio, the choice of solvent and other reaction parameters were studied in detail. The heterogeneous catalytic system gave a higher degree of chemoselectivity (99%) towards 4-hydroxypentan-2-one as compared to homogeneous catalyst when hydrogenation was carried out using water as a solvent. The immobilized ruthenium-phenanthroline complex was easily separated and reused.
Deshmukh, Amit,Kinage, Anil,Kumar, Rajiv,Meijboom, Reinout
body text
p. 114 - 120
(2011/02/23)

PREPARATION OF DERIVATIVE OF POLYHYDRIC ALCOHOLS
A method for converting a polyhydric alcohol into propylene glycol and butanediols is disclosed. Also disclosed are methods for converting polyhydric alcohols into three-carbon products and four-carbon products. Also disclosed are methods for maximizing conversion of polyhydric alcohols and minimizing formation of reaction products that are difficult to remove from the desired product. In other embodiments, methods are described to optimize use of reactants, including hydrogen, in hydrogenolysis of polyhydric alcohols.
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Page/Page column 18-19; 25

(2008/12/08)

Hydrogenolysis of Glycerol and Products Produced Therefrom
Processes for the hydrogenolysis of glycerol, as well as products produced therefrom are disclosed.
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Page/Page column 6

(2008/06/13)

Chemoselective hydrolysis of terminal isopropylidene acetals in acetonitrile using molecular iodine as a mild and efficient catalyst
A simple, mild and efficient method for deprotection of acetonides in the presence of molecular iodine is described. Acid labile protecting groups such as PMB, OMe, OBn, allyl and propargyl are compatible with the reaction conditions, while TBS, TBDPS, TMS and THP ethers were unstable under the same conditions.
Yadav,Satyanarayana,Raghavendra,Balanarsaiah
p. 8745 - 8748
(2007/10/03)

Facile deoxygenation of dicarbonyl compounds using a samarium diiodide-additive system
The reduction of α- and β-dicarbonyl compounds was investigated with samarium diiodide in the presence of additive. Diketones and ketocarboxylic acids were easily reduced at room temperature to give the mono-alcohols in good to excellent yield, and ketoester afforded the saturated ester as the major product in moderate yield. These reductions containing the reductive deoxygenation can be rapidly performed under the facile and mild conditions by this method.
Kamochi, Yasuko,Kudo, Tadahiro,Masuda, Toshinobu,Takadate, Akira
p. 1017 - 1020
(2007/10/03)

DERMATOLOGICAL COMPOSITIONS AND METHODS
Disclosed are methods and compositions for regulating the melanin content of mammalian melanocytes; regulating pigmentation in mammalian skin, hair, wool or fur; treating or preventing various skin and proliferative disorders; by administration of various compounds, including alcohols, diols and/or triols and their analogues.
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(2008/06/13)

Treatment of neurodegenerative diseases
Disclosed are methods for increasing the differentiation of mammalian neuronal cells for purposes of treating neurodegenerative diseases or nerve damage by administration of various compounds including alcohols, diols and/or triols and their analogues.
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(2008/06/13)

Asymmetric hydrosilylation of ketones using trans-chelating chiral peralkylbisphosphine ligands bearing primary alkyl substituents on phosphorus atoms
Asymmetric hydrosilylation of simple ketones with diphenylsilane proceeded at -40 °C in the presence of a rhodium complex (0.001 - 0.01 molar amount) coordinated with a trans-chelating chiral bisphosphine ligand bearing linear alkyl substituents on the phosphorus atoms, (R,R)-(S,S)-Et-, Pr-, or BuTRAP, giving the corresponding optically active (S)- secondary alcohols with up to 97% ee. The asymmetric hydrosilylation using TRAP ligands with bulkier P-substituents resulted in much lower enantioselectivities. The EtTRAP-rhodium catalyst was also effective for asymmetric hydrosilylation of keto esters with a coordination site for a rhodium atom (up to 98% ee). Optically active symmetrical diols were obtained with up to 99% ee from the corresponding diketones via the asymmetric reduction using 2.5 molar amounts of diphenylsilane.
Kuwano, Ryoichi,Sawamura, Masaya,Shirai, Junya,Takahashi, Masatoshi,Ito, Yoshihiko
p. 485 - 496
(2007/10/03)

Treatment of diseases mediated by the nitric oxide/cGMP/protein kinase G pathway
Disclosed are methods and compositions for stimulating cellular nitric oxide (NO) synthesis, cyclic guanosine monophosphate levels (cGMP), and protein kinase G (PKG) activity for purposes of treating diseases mediated by deficiencies in the NO/cGMP/PKG signal transduction pathway, by administration of various compounds including alcohols, diols and/or triols and their analogues.
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(2008/06/13)

The S(H)i reaction at silicon - A new entry into cyclic alkoxysilanes
A new mild radical method for the preparation of cyclic five-membered alkoxysilanes is reported. This method comprises an intramolecular homolytic substitution reaction at silicon (S(H)i). Various leaving groups (SiMe3, GeMe3, SnMe3) were tested in the homolytic substitution reaction. We found that high yields were only obtained for silanes bearing a trimethyl-stannyl functionality as leaving group in the S(H)i reaction. Rate constants for the cyclization reaction were estimated by conducting standard competition experiments. Based on the kinetic data, more elaborate reaction sequences such as radical addition reactions with a subsequent S(H)i step were carried out. Stereoselective cyclization reactions were also investigated. Excellent 1,2 diastereoselectivities were observed. The products of the S(H)i reaction, cyclic alkoxysilanes, can easily be converted to the corresponding diol derivatives by Tamao-Fleming oxidation as demonstrated for several examples.
Studer, Armido,Steen, Hanno
p. 759 - 773
(2007/10/03)

Synthesis and Conformational Analysis of Six-Membered Cyclic Phenyl Phosphites
A procedure for synthesizing potentially anancomeric equatorial phenyl phosphites (cis-1 and eq-cis-2) is reported.Spectral characteristics and low-temperature NMR studies on the phenyl phosphites suggest that eq-cis-2 is a system with a predominant chair conformation in solution.On the contrary, cis-1 is conformationally heterogeneous.
Gordillo, Barbara,Garduno, Catalina,Guadarrama, Gerardo,Hernandez, Javier
p. 5180 - 5185
(2007/10/02)

Diols obtained via chemo and regioselective ring opening of epoxy alcohols: A straightforward synthesis of 2S,3S-octandiol
Epoxy alcohols are regio and chemoselectively opened to the corresponding iodohydrins and then reduced in situ to diols; the application of the described procedure leads to a short asymmetric of a well known pheromone. Also homoallylic (E and Z) epoxy alcohols and its benzylated derivatives shows high preference for regioselective opening affording the corresponding 1,3 diol.
Bonini, Carlo,Righi, Giuliana
p. 1531 - 1538
(2007/10/02)

Synthesis of 1,2-Dimethylpyrene, 1,3-Dimethylpyrene and 1,2,3-Trimethylpyrene
The title compounds have been prepared, starting from 1H-phenalene 1.The method described in this paper is an efficient procedure for introducing methyl groups into the A-ring of pyrene.
Hempenius, Mark A.,Lugtenburg, Johan,Cornelisse, Jan
p. 635 - 638
(2007/10/02)

ASYMMETRISCHE KATALYSEN, 68. ENANTIOSELEKTIVE HYDRIERUNG VON ACETYLACETON MIT NaBr/L-(+)-WEINSAEURE MODIFIZIERTEN UEBERGANGSMETALLEN
Enantioselective hydrogenation of acetylacetone AcacH to 4-hydroxy-2-pentanone HP and 2,4-pentanediol PD on various types of transition metal complexes modified with NaBr/L-(+)-tartaric acid was carried out.Finely divided catalysts prepared by cocondensation of the transition metals Cr, Mn, Fe, Co, Ni, the alloys Ni/Al, Ni/Zn, Ni/Cu, which were activated by NaOH treatment, and nickel powders with different surface areas were used.Transition metals and alloys obtained by condensation showed satisfactory enantioselectivity but had low hydrogenation activity.Modified nickel powders achieved high enantioselectivities and activities.The enantioselectivity could be correlated to the surface area of the nickel catalysts with a maximum between 5-7.5 m2/g.
Brunner, H.,Amberger, K.,Wiehl, J.
p. 571 - 584
(2007/10/02)

Stereochemical Studies of the Hydrogenation with an Asymmetrically Modified Raney Nickel Catalyst. The Hydrogenation of Acetylacetone
The hydrogenation of acetylacetone (I) over asymmetrically modified Raney nickel (MRNi) proceeded, step by step, as follows: Step 1 Step 2 acetylacetone (I) ------> 4-hydroxy-2-pentanone (III) ------> 2,4-pentanediol (II).It was demonstrated that the optical yield of Step 1 and the diastereomer excess of Step 2 are governed by the ratio of the stereo-differentiating reaction site to the non-stereo-differentiating reaction site on the catalyst.The stereochemistry of each step was also discussed based on the mode of the intermolecular hydrogen bondings between the substrate and tartaric acid adsorbed on the catalyst.RNi modified with a mixture of tartaric acid and NaBr (TA-NaBr-MRNi) gave the best result with respect to both Step 1 and Step 2.
Tai, Akira,Ito, Kazuhisa,Harada, Tadao
p. 223 - 227
(2007/10/02)