- New heterocyclic mono- and bis(α-hydroxymethyl)phosphinic acids: Synthesis and CuII binding abilities
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A simple and efficient method for the synthesis of (α-hydroxymethyl) phosphinic acids in a pyridine and imidazole series from their corresponding aldehydes and aqueous hypophosphorous acid was developed. The same reaction carried out with an excess of aldehyde in the presence of a mineral acid led mainly to the corresponding bis(α-hydroxymethyl)phosphinic acids in moderate yields. The coordination properties of these compounds towards Cu II ions were determined. Additionally, it was found that [(hydroxy)-(2-pyridyl)- and (hydroxy)(4-pyridyl)methyl]phosphinic acids were easy to cleave in aqueous sulfuric acid solutions, to form phosphorus acid (H3PO3) and the corresponding pyridinemethanols. The kinetics of the cleavage reaction was studied. On the basis of the obtained results, a mechanism of the cleavage was formulated. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Olszewski, Tomasz Krzysztof,Galezowska, Joanna,Boduszek, Bogdan,Kozlowski, Henryk
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Read Online
- Homoleptic cobalt(II) phenoxyimine complexes for hydrosilylation of aldehydes and ketones without base activation of cobalt(II)
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Air-stable, easy to prepare, homoleptic cobalt(II) complexes bearing pendant-modified phenoxyimine ligands were synthesized and determined. The complexes exhibited high catalytic performance for reducing aldehydes and ketones via catalytic hydrosilylation, where a hydrosilane and a catalytic amount of the cobalt(II) complex were added under base-free conditions. The reaction proceeded even in the presence of excess water, and excellent functional-group tolerance was observed. Subsequent hydrolysis gave the alcohol in high yields. Moreover, H2O had a critical role in activation of the Co(II) catalyst with hydrosilane. Several additional results also indicated that the cobalt(II) center acts as an active catalyst in the hydrosilylation of aldehydes and ketones.
- Hori, Momoko,Ishikawa, Ryuta,Koga, Yuji,Matsubara, Kouki,Mitsuyama, Tomoaki,Shin, Sayaka
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p. 1379 - 1387
(2021/05/29)
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- Metal-Free Deoxygenation of Amine N-Oxides: Synthetic and Mechanistic Studies
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We report herein an unprecedented combination of light and P(III)/P(V) redox cycling for the efficient deoxygenation of aromatic amine N-oxides. Moreover, we discovered that a large variety of aliphatic amine N-oxides can easily be deoxygenated by using only phenylsilane. These practically simple approaches proceed well under metal-free conditions, tolerate many functionalities and are highly chemoselective. Combined experimental and computational studies enabled a deep understanding of factors controlling the reactivity of both aromatic and aliphatic amine N-oxides.
- Lecroq, William,Schleinitz, Jules,Billoue, Mallaury,Perfetto, Anna,Gaumont, Annie-Claude,Lalevée, Jacques,Ciofini, Ilaria,Grimaud, Laurence,Lakhdar, Sami
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p. 1237 - 1242
(2021/06/01)
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- Novel quinolone-based potent and selective HDAC6 inhibitors: Synthesis, molecular modeling studies and biological investigation
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In this work we describe the synthesis of potent and selective quinolone-based histone deacetylase 6 (HDAC6) inhibitors. The quinolone moiety has been exploited as an innovative bioactive cap-group for HDAC6 inhibition; its synthesis was achieved by applying a multicomponent reaction. The optimization of potency and selectivity of these products was performed by employing computational studies which led to the discovery of the diethylaminomethyl derivatives 7g and 7k as the most promising hit molecules. These compounds were investigated in cellular studies to evaluate their anticancer effect against colon (HCT-116) and histiocytic lymphoma (U9347) cancer cells, showing good to excellent potency, leading to tumor cell death by apoptosis induction. The small molecules 7a, 7g and 7k were able to strongly inhibit the cytoplasmic and slightly the nuclear HDAC enzymes, increasing the acetylation of tubulin and of the lysine 9 and 14 of histone 3, respectively. Compound 7g was also able to increase Hsp90 acetylation levels in HCT-116 cells, thus further supporting its HDAC6 inhibitory profile. Cytotoxicity and mutagenicity assays of these molecules showed a safe profile; moreover, the HPLC analysis of compound 7k revealed good solubility and stability profile.
- Relitti, Nicola,Saraswati, A. Prasanth,Chemi, Giulia,Brindisi, Margherita,Brogi, Simone,Herp, Daniel,Schmidtkunz, Karin,Saccoccia, Fulvio,Ruberti, Giovina,Ulivieri, Cristina,Vanni, Francesca,Sarno, Federica,Altucci, Lucia,Lamponi, Stefania,Jung, Manfred,Gemma, Sandra,Butini, Stefania,Campiani, Giuseppe
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- Iron-catalyzed chemoselective hydride transfer reactions
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A Diaminocyclopentadienone iron tricarbonyl complex has been applied in chemoselective hydrogen transfer reductions. This bifunctional iron complex demonstrated a broad applicability in mild conditions in various reactions, such as reduction of aldehydes over ketones, reductive alkylation of various functionalized amines with functionalized aldehydes and reduction of α,β-unsaturated ketones into the corresponding saturated ketones. A broad range of functionalized substrates has been isolated in excellent yields with this practical procedure.
- Coufourier, Sébastien,Ndiaye, Daouda,Gaillard, Quentin Gaignard,Bettoni, Léo,Joly, Nicolas,Mbaye, Mbaye Diagne,Poater, Albert,Gaillard, Sylvain,Renaud, Jean-Luc
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supporting information
(2021/06/07)
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- Manganese-catalysed transfer hydrogenation of esters
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Manganese catalysed ester reduction using ethanol as a hydrogen transfer agent in place of dihydrogen is reported. High yields can be achieved for a range of substrates using 1 mol% of a Mn(i) catalyst, with an alkoxide promoter. The catalyst is derived from a tridentate P,N,N ligand.
- Oates, Conor L.,Widegren, Magnus B.,Clarke, Matthew L.
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p. 8635 - 8638
(2020/08/21)
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- Photochemical C-H Silylation and Hydroxymethylation of Pyridines and Related Structures: Synthetic Scope and Mechanisms
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Considering the synthetic relevance of heteroarenes in various areas ranging from organic synthesis to medicinal chemistry, developing practically simple methodologies to access functionalized heteroarenes is of a significant value. Described herein is an efficient approach for C-H silylation and hydroxymethylation of pyridines and related heterocycles by the combination of silanes or methanol with readily available N-methoxypyridinium ions with a low catalyst loading (2 mol %) under blue light irradiation. The synthetic importance of the developed reactions is demonstrated by the synthesis of biologically relevant compounds. Electron paramagnetic resonance spectroscopy, quantum yield measurements, and density-functional theory calculations allowed us to understand reaction mechanisms of both photocatalytic reactions.
- Rammal, Fatima,Gao, Di,Boujnah, Sondes,Hussein, Aqeel A.,Lalevée, Jacques,Gaumont, Annie-Claude,Morlet-Savary, Fabrice,Lakhdar, Sami
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p. 13710 - 13717
(2020/11/30)
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- Can Heteroarenes/Arenes Be Hydrogenated Over Catalytic Pd/C Under Ambient Conditions?
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Hydrogenation of over a dozen aromatic compounds, including both heteroarenes and arenes, over palladium on carbon (Pd/C, 1–100 molpercent) with H2-balloon pressure at room temperature is reported. Analyses using pyridine as a model substrate revealed that acetic acid was the best solvent, as using only 1 molpercent Pd/C provided piperidine quantitatively. Substrate scope analysis and density functional theory calculations indicated that reaction rates are highly dependent on frontier molecular orbital characteristics and the steric bulkiness of substituents. Moreover, the established method was used for the concise synthesis of the anti-Alzheimer drug donepezil (Aricept?).
- Tanaka, Nao,Usuki, Toyonobu
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p. 5514 - 5522
(2020/07/24)
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- Efficient One-Pot Reductive Aminations of Carbonyl Compounds with Aquivion-Fe as a Recyclable Catalyst and Sodium Borohydride
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A one-pot reductive amination of aldehydes and ketones with NaBH4 was developed with a view to providing efficient, economical and greener synthetic conditions. A recyclable iron-based Lewis catalyst, Aquivion-Fe, was used to promote imine formation in cyclopentyl methyl ether, followed by the addition of a small amount of methanol to the reaction mixture to enable C=N reduction by NaBH4. The protocol, applied to a wide number of amines and carbonyl compounds, resulted in ever complete conversion of these latter with excellent chemoselectivity towards the expected amination products in the most cases. Isolated yields, determined for a selection of the screened substrates, were found consistent with the previously obtained conversion and selectivity data. Cinacalcet, an important active pharmaceutical ingredient, was efficiently prepared by the title procedure.
- Airoldi, Veronica,Piccolo, Oreste,Roda, Gabriella,Appiani, Rebecca,Bavo, Francesco,Tassini, Riccardo,Paganelli, Stefano,Arnoldi, Sebastiano,Pallavicini, Marco,Bolchi, Cristiano
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supporting information
p. 162 - 168
(2019/12/11)
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- Catalyst-Free N-Deoxygenation by Photoexcitation of Hantzsch Ester
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A mild and operationally simple protocol for the deoxygenation of a variety of heteroaryl N-oxides and nitroarenes has been developed. A mixture of substrate and Hantzsch ester is proposed to result in an electron donor-acceptor complex, which upon blue-light irradiation undergoes photoinduced electron transfer between the two reactants to afford the products. N-oxide deoxygenation is demonstrated with 22 examples of functionally diverse substrates, and the chemoselective reduction of nitroarenes to the corresponding hydroxylamines is also shown.
- Cardinale, Luana,Jacobi Von Wangelin, Axel,Konev, Mikhail O.
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supporting information
(2020/02/15)
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- Peptidomimetic Vinyl Heterocyclic Inhibitors of Cruzain Effect Antitrypanosomal Activity
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Cruzain, an essential cysteine protease of the parasitic protozoan, Trypanosoma cruzi, is an important drug target for Chagas disease. We describe here a new series of reversible but time-dependent inhibitors of cruzain, composed of a dipeptide scaffold appended to vinyl heterocycles meant to provide replacements for the irreversible reactive "warheads" of vinyl sulfone inactivators of cruzain. Peptidomimetic vinyl heterocyclic inhibitors (PVHIs) containing Cbz-Phe-Phe/homoPhe scaffolds with vinyl-2-pyrimidine, vinyl-2-pyridine, and vinyl-2-(N-methyl)-pyridine groups conferred reversible, time-dependent inhibition of cruzain (Ki? = 0.1-0.4 μM). These cruzain inhibitors exhibited moderate to excellent selectivity versus human cathepsins B, L, and S and showed no apparent toxicity to human cells but were effective in cell cultures of Trypanosoma brucei brucei (EC50 = 1-15 μM) and eliminated T. cruzi in infected murine cardiomyoblasts (EC50 = 5-8 μM). PVHIs represent a new class of cruzain inhibitors that could progress to viable candidate compounds to treat Chagas disease and human sleeping sickness.
- Chenna, Bala C.,Li, Linfeng,Mellott, Drake M.,Zhai, Xiang,Siqueira-Neto, Jair L.,Calvet Alvarez, Claudia,Bernatchez, Jean A.,Desormeaux, Emily,Alvarez Hernandez, Elizabeth,Gomez, Jana,McKerrow, James H.,Cruz-Reyes, Jorge,Meek, Thomas D.
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p. 3298 - 3316
(2020/04/08)
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- Microwave-heated γ-Alumina Applied to the Reduction of Aldehydes to Alcohols
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The development of cheap and robust heterogeneous catalysts for the Meerwein-Ponndorf-Verley (MPV) reduction is desirable due to the difficulties in product isolation and catalyst recovery associated with the traditional use of homogeneous catalysts for MPV. Herein, we show that microwave heated γ-Al2O3 can be used for the reduction of aldehydes to alcohols. The reaction is efficient and has a broad substrates scope (19 entries). The products can be isolated by simple filtration, and the catalyst can be regenerated. With the use of microwave heating, we can direct the heating to the catalyst rather than to the whole reaction medium. Furthermore, DFT was used to study the reaction mechanism, and we can conclude that a dual-site mechanism is operative where the aldehyde and 2-propoxide are situated on two adjacent Al sites during the reduction. Additionally, volcano plots were used to rationalize the reactivity of Al2O3 in comparison to other metal oxides.
- Dhokale, Bhausaheb,Susarrey-Arce, Arturo,Pekkari, Anna,Runemark, August,Moth-Poulsen, Kasper,Langhammer, Christoph,H?relind, Hanna,Busch, Michael,Vandichel, Matthias,Sundén, Henrik
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p. 6344 - 6355
(2020/10/28)
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- Cyclopentadienone iron tricarbonyl complexes-catalyzed hydrogen transfer in water
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The development of efficient and low-cost catalytic systems is important for the replacement of robust noble metal complexes. The synthesis and application of a stable, phosphine-free, water-soluble cyclopentadienone iron tricarbonyl complex in the reduction of polarized double bonds in pure water is reported. In the presence of cationic bifunctional iron complexes, a variety of alcohols and amines were prepared in good yields under mild reaction conditions.
- Coufourier, Sébastien,Gaillard, Sylvain,Mbaye, Mbaye Diagne,Ndiaye, Daouda,Renaud, Jean-Luc
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supporting information
(2020/01/28)
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- 1-D manganese(ii)-terpyridine coordination polymers as precatalysts for hydrofunctionalisation of carbonyl compounds
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Reductive catalysis with earth-abundant metals is currently of increasing importance and shows potential in replacing precious metal catalysis. In this work, we revealed catalytic hydroboration and hydrosilylation of ketones and aldehydes achieved by a structurally defined manganese(ii) coordination polymer (CP) as a precatalyst under mild conditions. The manganese-catalysed methodology can be applied to a range of functionalized aldehydes and ketones with turnover numbers (TON) of up to 990. Preliminary results on the regioselective catalytic hydrofunctionalization of styrenes by the Mn-CP catalyst are also presented.
- Johnson, Jahvon,Li, Sihan,Mo, Zixuan,Neary, Michelle C.,Zeng, Haisu,Zhang, Guoqi,Zheng, Shengping
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p. 2610 - 2615
(2020/03/05)
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- A 4 - chloromethyl pyridine hydrochloride synthetic method
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The invention belongs to the field of organic synthesis, in particular to a 4 - chloromethyl pyridine hydrochloride synthetic method, the method comprises the following steps: (1) to 4 - methyl pyridine as raw materials, takes water as a solvent, the potassium permanganate oxide it to 4 - pyridine carboxylic acid, wherein 4 - methyl pyridine with potassium permanganate in a molar ratio of 1: 2.1 - 2.3, the oxidation temperature is 75 - 80 °C, heating 35 min, the reaction is complete the reaction liquid is adjusted to be acidic, and then cooling and filtering to obtain 4 - pyridine carboxylic acid; (2) 4 - pyridine carboxylic acid with methanol under acidic conditions to produce the 4 - pyridine carboxylic acid methyl ester, wherein the 4 - pyridine carboxylic acid with methanol in a molar ratio of 1: 1.3; (3) reduction of 4 - pyridine carboxylic acid methyl ester for 4 - pyridine methanol; (4) 4 - pyridine methanol with thionyl chloride reaction to obtain the target product 4 - chloromethyl pyridine hydrochloride, 4 - pyridine methanol with thionyl chloride in a molar ratio of 1: 1.1 - 1.3.
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- Microwave-assisted Cannizzaro reaction—Optimisation of reaction conditions
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The microwave-assisted Cannizzaro reaction was studied in order to develop fully reproducible synthetic protocols for transformation of aldehydes to carboxylic acid and alcohols. Optimised were the following process parameters: power, temperature, and time. Aromatic, heteroaromatic and aliphatic aldehydes were used in the studies. It was found that furfural, thiophene-2-carbaldehyde, pyridinecarboxaldehyde and aromatic aldehydes react under mild conditions, while 1-methyl-pyrrole-2-carboxaldehyde derivatives and aliphatic aldehydes require more drastic reaction conditions and a longer exposure time to microwave radiation.
- Janczewski, ?ukasz,Walczak, Ma?gorzata,Fr?czyk, Justyna,Kamiński, Zbigniew J.,Kolesińska, Beata
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supporting information
p. 3290 - 3300
(2019/11/05)
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- Borinic Acid Mediated Hydrosilylations: Reductions of Carbonyl Derivatives
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4-Fluoro-2-chlorophenylborinic acid acts as a precatalyst in the presence of phenylsilane for the facile reduction of ketones, aldehydes and imines. Notably, synergistic mediation of a tertiary amine was found essential to trigger silicon to boron hydride transfer to generate a key amine–diarylhydroborane Lewis complex.
- Chardon, Aurélien,Rouden, Jacques,Blanchet, Jér?me
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supporting information
p. 995 - 998
(2018/12/13)
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- Practical and selective hydroboration of aldehydes and ketones in air catalysed by an iron(ii) coordination polymer
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The in air catalytic hydroboration of ketones and aldehydes with pinacolborane by an iron(ii) coordination polymer (CP) is carried out under mild and solvent-free conditions. The precatalyst is highly active towards a wide range of substrates including functionalized ketones and aldehydes in the presence of KOtBu as an activator, achieving a high turnover number (TON) of up to 9500. Excellent chemoselectivity to aldehydes over ketones was also revealed, which is in sharp contrast with the results obtained under inert atmosphere using the same catalyst system. This catalyst observed here is not only highly efficient but also recyclable for reuse for at least 5 times without losing its effectiveness.
- Zhang, Guoqi,Cheng, Jessica,Davis, Kezia,Bonifacio, Mary Grace,Zajaczkowski, Cynthia
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p. 1114 - 1121
(2019/03/12)
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- MUSCARINIC M1 RECEPTOR POSITIVE ALLOSTERIC MODULATORS
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The present invention relates to compounds of formula (I), or their isotopic forms, stereoisomers, tautomers or pharmaceutically acceptable salt (s) thereof as muscarinic M1 receptor positive allosteric modulators (M1 PAMs). The present invention describes the preparation, pharmaceutical composition and the use of compound formula (I).
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- Visible-Light Photocatalyzed Deoxygenation of N-Heterocyclic N-Oxides
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A scalable and operationally simple method is described that allows for the chemoselective deoxygenation of a wide range of N-heterocyclic N-oxides (a total of 36 examples). This visible-light-induced protocol features the use of only commercially available reagents, room-temperature conditions, and unprecedented chemoselective removal of the oxygen atom in a quinoline N-oxide in the presence of a pyridine N-oxide in the same molecule through the judicious selection of a photocatalyst.
- Kim, Kyu Dong,Lee, Jun Hee
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supporting information
p. 7712 - 7716
(2019/01/03)
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- Stabilization of NaBH4 in Methanol Using a Catalytic Amount of NaOMe. Reduction of Esters and Lactones at Room Temperature without Solvent-Induced Loss of Hydride
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Rapid reaction of NaBH4 with MeOH precludes its use as a solvent for large-scale ester reductions. We have now learned that a catalytic amount of NaOMe (5 mol %) stabilizes NaBH4 solutions in methanol at 25 °C and permits the use of these solutions for the reduction of esters to alcohols. The generality of this reduction method was demonstrated using 22 esters including esters of naturally occurring chiral γ-butyrolactone containing dicarboxylic acids. This method permits the chemoselective reductions of esters in the presence of cyano and nitro groups and the reductive cyclization of a pyrrolidinedione ester to a fused five-membered furo[2,3-b]pyrrole and a (-)-crispine A analogue in high optical and chemical yields. Lactones, aliphatic esters, aromatic esters containing electron-withdrawing groups, and heteroaryl esters are reduced more rapidly than aryl esters containing electron-donating groups. The 11B NMR spectrum of the NaOMe-stabilized NaBH4 solutions showed a minor quartet due to monomethoxyborohydride (NaBH3OMe) that persisted up to 18 h at 25 °C. We postulate that NaBH3OMe is probably the active reducing agent. In support of this hypothesis, the activation barrier for hydride transfer from BH3(OMe)- onto benzoic acid methyl ester was calculated as 18.3 kcal/mol.
- Prasanth,Joseph, Ebbin,Abhijith,Nair,Ibnusaud, Ibrahim,Raskatov, Jevgenij,Singaram, Bakthan
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p. 1431 - 1440
(2018/02/09)
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- Mild and selective reduction of aldehydes utilising sodium dithionite under flow conditions
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We recently reported a novel hybrid batch-flow synthesis of the antipsychotic drug clozapine in which the reduction of a nitroaryl group is described under flow conditions using sodium dithionite. We now report the expansion of this method to include the reduction of aldehydes. The method developed affords yields which are comparable to those under batch conditions, has a reduced reaction time and improved space-time productivity. Furthermore, the approach allows the selective reduction of aldehydes in the presence of ketones and has been demonstrated as a continuous process.
- Neyt, Nicole C.,Riley, Darren L.
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supporting information
p. 1529 - 1536
(2018/07/05)
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- Photoinduced Electron Transfer (PET)-Mediated Fragmentation of Picolinium-Derived Redox Probes
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The photolysis of covalently linked N-alkyl picolinium phenylacetate—carbazole dyads was analyzed experimentally and by using density functional theory (DFT) and time dependent-DFT (TD-DFT) calculations. In contrast to earlier observations efficient one and two-photon fragmentations conditions were found for 15 c (δu=0.16 GM at 730 nm) opening the way for the design of a novel class of “caged” compounds.
- Dunkel, Petra,Barosi, Anna,Dhimane, Hamid,Maurel, Fran?ois,Dalko, Peter I.
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p. 12920 - 12931
(2018/08/11)
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- Ruthenium-Catalyzed Deaminative Hydrogenation of Aliphatic and Aromatic Nitriles to Primary Alcohols
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The deaminative hydrogenation of nitriles towards alcohols is a useful reaction to transform nitriles into alcohols with NH3 as the sole byproduct. Using the simple and robust RuHCl(CO)(PPh3)3 complex as a catalyst, at low H2 pressures a series of aliphatic and aromatic nitriles could be transformed into the corresponding alcohols. Suitable solvent systems for these reactions were 1,4-dioxane/water and EtOH/water mixtures. In most cases, the selectivity for the alcohols was excellent, and the corresponding amines were formed only in trace amounts.
- Molnár, István Gábor,Calleja, Pilar,Ernst, Martin,Hashmi, A. Stephen K.,Schaub, Thomas
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p. 4175 - 4178
(2017/10/09)
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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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- Transition metal free catalytic hydroboration of aldehydes and aldimines by amidinato silane
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The transition metal free catalytic hydroboration of aldehydes and ketones is very limited and has not been reported with a well-defined silicon(iv) compound. Therefore, we chose to evaluate the previously reported silicon(iv) hydride [PhC(NtBu)2SiHCl2], (1) as a single component catalyst and found that it catalyzes the reductive hydroboration of a range of aldehydes with pinacolborane (HBpin) under ambient conditions. In addition, compound 1 can catalyze imine hydroboration. DFT calculation was carried out to understand the mechanism.
- Bisai, Milan Kumar,Pahar, Sanjukta,Das, Tamal,Vanka, Kumar,Sen, Sakya S.
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p. 2420 - 2424
(2017/03/08)
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- Synthetic method of 4-pyridylaldehyde
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The invention relates to the field of organic chemistry, in particular to a synthetic method of 4-pyridylaldehyde. The synthetic method comprises the following steps: 1, taking 4-methyl pyridine as a raw material and obtaining 4-pyridine nitrogen oxide through oxidation reaction under an acidic condition; 2, synthesizing the 4-pyridine nitrogen oxide into acetic acid-4-pyridine methyl ester through acetic anhydride rearrangement; 3, hydrolyzing the acetic acid-4-pyridine methyl ester to obtain 4-pyridine methanol; 4, performing oxidation reaction on the 4-pyridine methanol to obtain the 4-pyridylaldehyde. After the synthetic method is adopted, the 4-methyl pyridine is used as the raw material, and the 4-pyridine methanol is obtained through N-oxidation, rearrangement and hydrolyzation and is further oxidized to obtain the 4-pyridylaldehyde. The synthetic method provided by the invention is high in total yield, low in raw material price, short in reaction time, mild in condition, and simple in process operation.
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Paragraph 0035; 0037; 0040; 0045
(2017/11/18)
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- Polyurethane nanomicelles: A novel eco-friendly and efficient polymeric ionic solvent for the Cannizzaro reaction
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Aqueous polyurethane dispersions (APUDs) are commodity synthetic polymers and have a broad range of well-known applications, nevertheless their possible use as a green catalyst or ionic solvent is yet unknown. Here, we demonstrate how a polyurethane dispersion facilitates the progress of the Cannizzaro reaction under very mild alkaline conditions. We introduce anionic polyurethane nanomicelles as an expeditious green polymer ionic solvent for the Cannizzaro reaction. The reusable and novel eco-friendly polymer solvent, excellent yields of the products, low reaction times and low reaction temperatures are the main advantages of this reaction.
- Daemi, Hamed,Barikani, Mehdi,Jahani, Mehdi
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supporting information
p. 2121 - 2125
(2016/03/19)
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- Organoborane-Catalyzed Hydrogenation of Unactivated Aldehydes with a Hantzsch Ester as a Synthetic NAD(P)H Analogue
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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
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supporting information
p. 2037 - 2041
(2015/09/01)
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- Laccase-Mediator System for Alcohol Oxidation to Carbonyls or Carboxylic Acids: Toward a Sustainable Synthesis of Profens
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By combining two green and efficient catalysts, such as the commercially available enzyme laccase from Trametes versicolor and the stable free radical 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), the oxidation in water of some primary alcohols to the corresponding carboxylic acids or aldehydes and of selected secondary alcohols to ketones can be accomplished. The range of applicability of bio-oxidation is widened by applying the optimized protocol to the oxidation of enantiomerically pure 2-arylpropanols (profenols) into the corresponding 2-arylpropionic acids (profens), in high yields and with complete retention of configuration.
- Galletti, Paola,Pori, Matteo,Funiciello, Federica,Soldati, Roberto,Ballardini, Alberto,Giacomini, Daria
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p. 2684 - 2689
(2016/12/23)
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- PROCESS FOR PRODUCTION OF AROMATIC ALCOHOL OR HETEROCYCLIC AROMATIC ALCOHOL
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A process of production of an aromatic alcohol or a heterocyclic aromatic alcohol, containing a step of reacting an aromatic amine or a heterocyclic aromatic amine having an aromatic ring or a heterocyclic aromatic ring having thereon at least one substituent -CHR1NR2R3 (wherein R1, R2 and R3 each independently represent hydrogen, an alkyl group having from 1 to 4 carbon atoms, or a benzyl group), with an alcohol, in the presence of a basic catalyst.
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Paragraph 0033-0034
(2013/11/19)
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- Antimalarial and structural studies of pyridine-containing inhibitors of 1-deoxyxylulose-5-phosphate reductoisomerase
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1-Deoxy-d-xylulose-5-phosphate reductoisomerase (DXR) in the nonmevalonate isoprene biosynthesis pathway is a target for developing antimalarial drugs. Fosmidomycin, a potent DXR inhibitor, showed safety as well as efficacy against Plasmodium falciparum malaria in clinical trials. On the basis of our previous quantitative structure-activity relationship (QSAR) and crystallographic studies, several novel pyridine-containing fosmidomycin derivatives were designed, synthesized, and found to be highly potent inhibitors of P. falciparum DXR (PfDXR) having Ki values of 1.9-13 nM, with the best one being ~11× more active than fosmidomycin. These compounds also potently block the proliferation of multidrug resistant P. falciparum with EC 50 values as low as 170 nM. A 2.3 A? crystal structure of PfDXR in complex with one of the inhibitors is reported, showing that the flexible loop of the protein undergoes conformational changes upon ligand binding and a hydrogen bond and favorable hydrophobic interactions between the pyridine group and the PfDXR account for the enhanced activity.
- Xue, Jian,Diao, Jiasheng,Cai, Guobin,Deng, Lisheng,Zheng, Baisong,Yao, Yuan,Song, Yongcheng
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supporting information
p. 278 - 282
(2013/03/29)
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- Rational design and synthesis of 4-substituted 2-pyridin-2-ylamides with inhibitory effects on SH2 domain-containing inositol 5′-phosphatase 2 (SHIP2)
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Novel 4-substituted 2-pyridin-2-ylamides were developed using in-silico ligand-based drug design (LBDD) in an attempt to identify inhibitors of SH2-containing 5′-inositol phosphatase 2 (SHIP2), which is implicated in insulin-resistant type 2 diabetes. Among the compounds synthesized, N-[4-(4-chlorobenzyloxy)pyridin-2-yl]-2-(2,6-difluorophenyl)- acetamide (CPDA, 4a) was identified as a potent SHIP2 inhibitor. CPDA was found to enhance in vitro insulin signaling through the Akt pathway more efficiently than the previously reported SHIP2 inhibitor AS1949490, and ameliorated abnormal glucose metabolism in diabetic (db/db) mice.
- Ichihara, Yoshinori,Fujimura, Ryohei,Tsuneki, Hiroshi,Wada, Tsutomu,Okamoto, Kentaro,Gouda, Hiroaki,Hirono, Shuichi,Sugimoto, Kenji,Matsuya, Yuji,Sasaoka, Toshiyasu,Toyooka, Naoki
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p. 649 - 660
(2013/05/09)
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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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- Selective reduction of aldehydes and ketones to alcohols with ammonia borane in neat water
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Chemoselective reduction of various carbonyl compounds to alcohols with ammonia borane (AB), a nontoxic, environmentally benign, and easily handled reagent, in neat water was achieved in quantitative conversions and high isolated yields. Interestingly, α- and β-keto esters were selectively reduced to corresponding hydroxyl esters by AB, while diols were obtained when sodium borohydride was used as a reducing agent. The procedure is also compatible with the presence of a variety of base-labile protecting groups, such as tosyl, acetyl, benzoyl, ester groups, and acid-labile protecting groups such as trityl and TBDMS groups, and others, such as the unsaturated double bond, nitro and cyano groups. Finally, a kilo scale reaction of methyl benzoylformate with AB was conducted in water and gave methyl mandelate in 94% yield.
- Shi, Lei,Liu, Yingying,Liu, Qingfeng,Wei, Bin,Zhang, Guisheng
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experimental part
p. 1372 - 1375
(2012/06/04)
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- Convenient and improved protocols for the hydrogenation of esters using Ru catalysts derived from (P,P), (P,N,N) and (P,N,O) ligands
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An improved protocol where a pre-cursor, [Ru(Cl)2(NBD)(Py) 2], is treated with ligands to form [RuCl2(bidentate ligand)(diamine)] pre-catalysts for ester hydrogenation is reported. This family of catalysts, as well as a range of ruthenium complexes of tridentate P^N^X (X = NR2, OH) ligands have been investigated in the hydrogenation of aromatic esters. A range of aromatic esters can be hydrogenated in high yields at temperatures between 30 °C and 100 °C.
- Carpenter, Ian,Fuentes, Jose A.,Clarke, Matthew L.,Eckelmann, Susan C.,Kuntz, Michael T.,France, Marcia B.
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p. 10136 - 10140,5
(2012/12/11)
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- Convenient and improved protocols for the hydrogenation of esters using Ru catalysts derived from (P,P), (P,N,N) and (P,N,O) ligands
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An improved protocol where a pre-cursor, [Ru(Cl)2(NBD)(Py) 2], is treated with ligands to form [RuCl2(bidentate ligand)(diamine)] pre-catalysts for ester hydrogenation is reported. This family of catalysts, as well as a range of ruthenium complexes of tridentate P^N^X (X = NR2, OH) ligands have been investigated in the hydrogenation of aromatic esters. A range of aromatic esters can be hydrogenated in high yields at temperatures between 30 °C and 100 °C.
- Carpenter, Ian,Eckelmann, Susan C.,Kuntz, Michael T.,Fuentes, Jose A.,France, Marcia B.,Clarke, Matthew L.
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p. 10136 - 10140
(2013/01/14)
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- Highly efficient gold nanoparticle catalyzed deoxygenation of amides, sulfoxides, and pyridine N-oxides
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Selective deoxygenation is one of the most important reactions in the areas of total synthesis, biological chemistry, and transformation of renewable biomass resources.To date, many useful methods for the selective deoxygenation of oxygen-containing organic molecules, such as amides, nitro compounds, epoxides, sulfoxides, and those with Noxide groups, have been developed. However, these methods often include stoichiometric reactions. Some successful catalysts have been reported,but most of them are homogeneous systems and still suffer from low activities and selectivities, harsh reaction conditions, and tedious workup procedures. Therefore, further development of highly efficient heterogeneous catalysts for selective deoxygenations is highly desired.
- Mikami, Yusuke,Noujima, Akifumi,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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experimental part
p. 1768 - 1772
(2011/03/21)
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- Selective photocatalytic reductions of nitrobenzene derivatives using PbBiO2X and blue light
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Blue light irradiation of heterogeneous photocatalysts PbBiO2X (X = Cl, Br) in the presence of triethanolamine as an electron donor leads to hydrogen evolution, and the selective, clean and complete reduction of nitrobenzene derivatives to their corresponding anilines. The Royal Society of Chemistry.
- Fueldner, Stefan,Pohla, Patrick,Bartling, Hanna,Dankesreiter, Stephan,Stadler, Roland,Gruber, Michael,Pfitzner, Arno,Koenig, Burkhard
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supporting information; experimental part
p. 640 - 643
(2011/05/04)
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- Purification and characterization of an NADH-dependent alcohol dehydrogenase from Candida maris for the synthesis of optically active 1-(pyridyl)ethanol derivatives
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A novel (R)-specific alcohol dehydrogenase (AFPDH) produced by Candida maris IFO10003 was purified to homogeneity by ammonium sulfate fractionation, DEAE-Toyopearl, and Phenyl-Toyopearl, and characterized. The relative molecular mass of the native enzyme was found to be 59,900 by gel filtration, and that of the subunit was estimated to be 28,900 on SDS-polyacrylamide gel electrophoresis. These results suggest that the enzyme is a homodimer. It required NADH as a cofactor and reduced various kinds of carbonyl compounds, including ketones and aldehydes. AFPDH reduced acetylpyridine derivatives, β-keto esters, and some ketone compounds with high enantioselectivity. This is the first report of an NADH-dependent, highly enantioselective (R)-specific alcohol dehydrogenase isolated from a yeast. AFPDH is a very useful enzyme for the preparation of various kinds of chiral alcohols.
- Kawano, Shigeru,Yano, Miho,Hasegawa, Junzo,Yasohara, Yoshihiko
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experimental part
p. 1055 - 1060
(2012/02/03)
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- NOVEL BENZODIOXANE AND BENZOXAZINE DERIVATIVES USEFUL AS CC CHEMOKINE RECEPTOR LIGANDS
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The present invention relates to benzodioxane and benzoxazine derivatives that act as ligands for CC chemokine receptors, such as CCR1. The invention also relates to methods of preparing the compounds, compositions containing the compounds, and to methods of treatment using the compounds.
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Page/Page column 81
(2010/06/22)
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- Green-light photocatalytic reduction using dye-sensitized TiO2 and transition metal nanoparticles
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Nitrobenzenes are cleanly reduced to anilines using Ru-sensitized TiO 2 photocatalysts and green light irradiation, if very small amounts of transitions metal salts are added, which form metal nanoparticles of narrow size distribution under the experimental conditions. The catalyst system is prepared by simple mixing of the components and is therefore easy to apply in organic synthesis. As light sources, commercial high power LEDs or sunlight are used. We report the optimization of the reaction conditions, the effect of trace amounts of added metal salts and demonstrate the use of green light photoreduction in the conversion of several nitrobenzene derivatives.
- Fueldner, Stefan,Mild, Ralph,Siegmund, Heiko Ingo,Schroeder, Josef A.,Gruber, Michael,Koenig, Burkhard
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experimental part
p. 400 - 406
(2010/08/06)
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- An environmentally benign electrochemical process for the reduction of carboxylic acid hydrazides to amides
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The transformation of acid hydrazides to primary amides is of certain relevance for the organic synthesis of complex molecules. While existing methods require harsh reaction conditions, we present an electrochemical approach in which monoacylhydrazines are reduced to primary amides in 40-90% yield in a divided electrochemical cell with a tin cathode. This method proved superior to reduction by sodium/mercury or lithium/biphenyl in terms of yield and practicability. Most importantly, the new method is distinguished by its tolerance of aryl halogen and olefinic groups. Georg Thieme Verlag Stuttgart.
- Mentel, Matthias,Beier, Matthias J.,Breinbauer, Rolf
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experimental part
p. 1463 - 1468
(2009/12/06)
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- METHOD FOR PRODUCING HETEROAROMATIC ALCOHOLS
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A process for preparing heteroaromatic alcohols by catalytically hydrogenating heteroaromatic carboxylic acids or esters thereof by hydrogenating with hydrogen in the presence of a ruthenium-phosphine complex in an organic solvent.
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Page/Page column 1-2
(2009/03/07)
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- Tetrahydropyrimidine derivatives as efficient organic reductants for transfer hydrogenation
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Two six-membered heterocyclic organic reductants, 1-acetyl-2,3-dimethyltetrahydropyrimidine (ADMP) and 1-tosyl-2,3-dimethyltetrahydro-pyrimidine (TDMP), were designed and synthesized for transfer hydrogenation. It was shown that both the two reductants could directly reduce a variety of aldehydes and imines to the corresponding saturated products in good yields.
- Zhang, Yongbin,Zhou, Guofu,Guo, Wei
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experimental part
p. 1541 - 1548
(2009/12/24)
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- Revisiting the Meerwein-Ponndorf-Verley reduction: A sustainable protocol for transfer hydrogenation of aldehydes and ketones
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An economical and sustainable transfer hydrogenation for aldehydes and ketones is described. The general protocol is mild, chemo-selective and, importantly, uses neither precious nor non-precious metals and even no ligands. The Royal Society of Chemistry 2009.
- Polshettiwar, Vivek,Varma, Rajender S.
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experimental part
p. 1313 - 1316
(2010/05/02)
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- Catalytic deoxygenation of pyridine N-oxides with N-fused porphyrin rhenium complexes
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Deoxygenation reactions of pyridine N-oxide derivatives catalyzed by N-fused porphyrin rhenium(VII) trioxo complexes are developed, affording the corresponding pyridine derivatives in quantitative yields with excellent turnover numbers up to 340,000.
- Toganoh, Motoki,Fujino, Keitaro,Ikeda, Shinya,Furuta, Hiroyuki
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p. 1488 - 1491
(2008/09/18)
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- 1-Acetyl-2,3-dimethylimidazolidine: A novel organic reductant for transfer hydrogenation
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1-Acetyl-2,3-dimethylimidazolidine was synthesized and was shown to be able to directly reduce a series of aromatic, aliphatic and α,β- unsaturated aldehydes as well as imines in high yields. Georg Thieme Verlag Stuttgart.
- Li, Donghong,Zhang, Yongbin,Zhou, Guofu,Guo, Wei
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p. 225 - 228
(2008/12/20)
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- A convenient and general iron-catalyzed hydrosilylation of aldehydes
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A general and highly chemoselective hydrosilylation of aldehydes using iron catalysts is reported. Fe(OAc)2 in the presence of tricyclohexylphosphine as ligand and polymethylhydrosiloxane (PMHS) as an economical hydride source forms an efficient catalyst system for the hydrosilylation of a variety of aldehydes. Aryl, heteroaryl, alkyl and α,β-unsaturated aldehydes are successfully reduced to the corresponding primary alcohols. Broad substrate scope and high tolerance against several functional groups make the process synthetically useful.
- Shaikh, Nadim S.,Junge, Kathrin,Beller, Matthias
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p. 5429 - 5432
(2008/09/19)
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- Organo-base mediated Cannizzaro reaction
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The organo-base, 1,1,3,3-tetramethylguanidine, mediates the Cannizzaro reaction of reactive aromatic aldehydes in water thus providing the corresponding alcohols and acids. Application of formaldehyde as a sacrificial aldehyde for the cross-Cannizzaro reaction is also presented.
- Basavaiah, Deevi,Sharada, Duddu S.,Veerendhar, Ainelly
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p. 5771 - 5774
(2007/10/03)
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