- Ru/g-C3N4as an efficient catalyst for selective hydrogenation of aromatic diamines to alicyclic diamines
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A series of Ru/g-C3N4materials with highly dispersed Ru were firstly prepared by an ultrasonic impregnation method using carbon nitride as a support. The catalysts were characterized by various techniques including BET and elemental analysis, ICP-AES, XPS, XRD, CO2-TPD and TEM. The results demonstrated that Ru/g-C3N4materials with a mesoporous structure and highly dispersed Ru were successfully prepared. The chemo-selective hydrogenation ofp-phenylenediamine (PPDA) to 1,4-cyclohexanediamine (CHDA) over Ru/g-C3N4as a model reaction was investigated in detail. PPDA conversion of 100% with a CHDA selectivity of more than 86% could be achieved under mild conditions. It can be inferred that the carbon nitride support possessed abundant basic sites and the Ru/g-C3N4-Tcatalysts provided suitable basicity for the aromatic ring hydrogenation. Compared to the N-free Ru/C catalyst, the involvement of nitrogen species in Ru/g-C3N4remarkably improved the catalytic performance. In addition, the recyclability of the catalyst demonstrated that the aggregation of Ru nanoparticles was responsible for the decrease of the catalytic activity. Furthermore, this strategy also could be expanded to the selective hydrogenation of other aromatic diamines to alicyclic diamines.
- Cao, Junya,Cao, Yan,Chen, Jiaqiang,Han, Fenggang,He, Peng,Huang, Xiaoyu,Li, Huiquan,Wang, Liguo,Yang, Huanhuan
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p. 16515 - 16525
(2020/05/13)
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- Modulating: Trans -imination and hydrogenation towards the highly selective production of primary diamines from dialdehydes
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Bio-based primary diamines are important building blocks for sustainable bio-polymers, but their synthesis remains challenging due to the high susceptibility to polymerization. Herein, we have developed a new strategy to suppress the polymerization by employing a more nucleophilic alkylamine to scavenge the dialdehyde and a Co/ZrO2 catalyst to regulate the trans-imination and hydrogenation activity. With this strategy, 2,5-bis(aminomethyl)furan (BAMF), a promising monomer for the production of new polyamides and polyureas, is successfully synthesized via the reductive amination of biomass-derived 2,5-diformylfuran (DFF) under a H2 and NH3 atmosphere with an unprecedentedly high selectivity up to 95%. This strategy is applicable to the reductive amination of other biomass-derived dialdehydes, thus paving a new way to bio-based diamine monomers. This journal is
- Hao, Rui,Li, Lin,Liu, Fei,Qi, Haifeng,Su, Yang,Wang, Aiqin,Yang, Jingyi,Zhang, Leilei,Zhang, Tao
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p. 6897 - 6901
(2020/11/09)
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- One-pot Synthesis of 4-Aminocyclohexanol Isomers by Combining a Keto Reductase and an Amine Transaminase
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The efficient multifunctionalization by one-pot or cascade catalytic systems has developed as an important research field, but is often challenging due to incompatibilities or cross-reactivities of the catalysts leading to side product formation. Herein we report the stereoselective preparation of cis- and trans-4-aminocyclohexanol from the potentially bio-based precursor 1,4-cyclohexanedione. We identified regio- and stereoselective enzymes catalyzing reduction and transamination of the diketone, which can be performed in a one-pot sequential or cascade mode. For this, we identified regioselective keto reductases for the selective mono reduction of the diketone to give 4-hydroxycyclohexanone. The system is modular and by choosing stereocomplementary amine transaminases, both cis- and trans-4-aminocyclohexanol were synthesized with good to excellent diastereomeric ratios. Furthermore, we identified an amine transaminase that produces cis-1,4-cyclohexanediamine with diastereomeric ratios >98 : 2. These examples highlight that the high selectivity of enzymes enable short and stereoselective cascade multifunctionalizations to generate high-value building blocks from renewable starting materials. Introduction.
- Sviatenko, Olha,Ríos-Lombardía, Nicolás,Morís, Francisco,González-Sabín, Javier,Venkata Manideep, Kollipara,Merdivan, Simon,Günther, Sebastian,Süss, Philipp,H?hne, Matthias
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p. 5794 - 5799
(2019/08/30)
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- A metagenomics approach for new biocatalyst discovery: Application to transaminases and the synthesis of allylic amines
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Transaminase enzymes have significant potential for the sustainable synthesis of amines using mild aqueous reaction conditions. Here a metagenomics mining strategy has been used for new transaminase enzyme discovery. Starting from oral cavity microbiome samples, DNA sequencing and bioinformatics analyses were performed. Subsequent in silico mining of a library of contiguous reads built from the sequencing data identified 11 putative Class III transaminases which were cloned and overexpressed. Several screening protocols were used and three enzymes selected of interest due to activities towards substrates covering a wide structural diversity. Transamination of functionalized cinnamaldehydes was then investigated for the production of valuable amine building blocks.
- Baud, Damien,Jeffries, Jack W. E.,Moody, Thomas S.,Ward, John M.,Hailes, Helen C.
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p. 1134 - 1143
(2017/08/14)
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- Ruthenium-Na2CO3-catalyzed one-pot synthesis of ring-hydrogenated carbamates from aromatic amines and organic carbonates under H2
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A facile and efficient one-pot procedure for the synthesis of ring hydrogenated carbamates from aromatic amine and alkylene carbonate under H2 gas pressure has been developed using a heterogeneous catalyst system comprising ruthenium and alkali metal carbonates. The effects of temperature, H2 pressure, catalyst (types of loaded metal and their supports), molar ratio of substrate/catalyst, and solvent were also investigated. Among the alkali metal carbonates, the sodium carbonate was found as best promoter for nucleophilic attack and ring-opening (NARO) reaction and thus increased the yield of ring hydrogenated carbamate up to 88% when using Ru/C as ring hydrogenation (RH) catalyst. This catalyst system could be reused at least five times without signi?cant loss of activity, which makes this process cost-effective and eco-friendly.
- Cho, Jin Ku,Kim, Hoon Sik,Kim, Yong Jin,Mishra, Vivek,Shin, Seung-Han,Suh, Young-Woong
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- PROCESS FOR THE DIRECT AMINATION OF ALCOHOLS USING AMMONIA TO FORM PRIMARY AMINES BY MEANS OF A XANTPHOS CATALYST SYSTEM
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The present invention relates to a chemocatalytic liquid-phase process for the direct one-stage amination of alcohols to primary amines by means of ammonia in high yields using a catalyst system containing at least one transition metal compound and a xantphos ligand.
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Paragraph 0063
(2014/01/08)
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- Improved ruthenium-catalyzed amination of alcohols with ammonia: Synthesis of diamines and amino esters
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Diamination of diols: The first homogeneously catalyzed diaminations of primary and secondary diols with ammonia give the corresponding diamines. Other primary as well as secondary alcohols including hydroxy-substituted esters can also be efficiently converted to primary amines. This atom-efficient and selective amination method proceeds in an ammonia atmosphere without additional hydrogen sources. Copyright
- Imm, Sebastian,Baehn, Sebastian,Zhang, Min,Neubert, Lorenz,Neumann, Helfried,Klasovsky, Florian,Pfeffer, Jan,Haas, Thomas,Beller, Matthias
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supporting information; experimental part
p. 7599 - 7603
(2011/10/01)
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- QUINOLINE, TETRAHYDROQUINOLINE AND PYRIMIDINE DERIVATIVES AS MCH ANTAGONIST
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The present invention relates to compounds of the Formula (I) wherein Q is: which act as MCH receptor antagonists. These compositions are useful in pharmaceutical compositions whose use includes prophylaxis or treatment of improving memory function, sleeping and arousal, anxiety, depression, mood disorders, seizure, obesity, diabetes, appetite and eating disorders, cardiovascular disease, hypertension, dyslipidemia, myocardial infarction, binge eating disorders including bulimia, anorexia, mental disorders including manic depression, schizophrenia, delirium, dementia, stress, cognitive disorders, attention deficit disorder, substance abuse disorders and dyskinesias including Parkinson's disease, epilepsy, and addiction.
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Page/Page column 163
(2010/02/08)
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- Method for producing cyclohexanediamines
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1,n-cyclohexanediamines (n=2, 3, 4) of general formula (I), wherein one of the radicals R1to R3is an amino group and the two others mean hydrogen, are produced from the corresponding cyclohexanediols and ammonia in the presence of a catalyst containing cobalt, at 100° to 350° C. and 50 to 300 bar. The compounds that can be produced according to the invention are structural elements for polymers, especially polyamides, polyimides, polyurea or polyurethanes, and ligands for cytostatically effective transition metal complexes.
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Page column 3
(2008/06/13)
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- Synthesis of 1,4-diaminocyclohexane in supercritical ammonia
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The amination of 1,4-cyclohexanediol in supercritical ammonia has been studied in a continuous fixed-bed reactor at 135 bar. An unsupported cobalt catalyst stabilized by 5 wt% Fe afforded the main reaction products 4-aminocyclohexanol and 1,4-diaminocyclohexane with a cumulative selectivity of 97% at 76% conversion. Excess of ammonia and short contact time favored the desired reactions. At low and high conversions the amination selectivity decreased due to the formation of dimers and oligomers and degradation products. Recycling of the unreacted diol and amino alcohol intermediate can provide an alternative economic process for the synthesis of 1,4-diaminocyclohexane.
- Fischer,Mallat,Baiker
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p. 289 - 291
(2007/10/03)
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- Linear oligomeric polychelant compounds
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Linear oligomer polychelant compounds and chelates formed therewith have alternating chelant and linker moieties bound together by amide or ester moieties. The compounds have between 3 and 100 chelant moieties, at least one of which complexes a paramagnetic metal ion. The polychelants and especially their paramagnetic metal polychelates are particularly suitable for diagnostic imaging.
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- Cosmetic composition containing an amide-amine type condensate, and a cosmetic treating process using said condensate
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A cosmetic composition for improving the suppleness of the skin or hair and for protecting the keratin of the skin or hair from degradation by atmospheric agents or light comprises in a cosmetic or dermatologic acceptable vehicle a saturated condensate resulting from the polyaddition of a bis-acrylamide and a sterically hindered primary diamine, the condensate being saturated by hydrogenation or by addition of a thiol or an amine on the double bonds of the acrylamide residue.
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- Silicone containing bis-thioether aromatic amines
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A silicone containing bis-thioether aromatic amine has a chemical structure wherein an aromatic nucleus at each end of the chemical radical is chemically bonded to the remainder of the chemical radical by either sulfur, sulfoxide or sulfone.
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- Novel polytriazine compounds
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Novel tetraalkyl piperidine radical containing polytriazine compounds are produced by reacting a dihalogen-triazine with a bifunctional compound containing amine, alcohol, mercaptan or phenol groups at least one of the bifunctional compounds containing a tetraalkyl piperidine radical. The compounds are valuable light stabilizers for synthetic polymers, particularly polyolefin in the form of fibers or films.
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- Preparation of esters of phosphorus acids
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Esters of phosphorus acids are prepared by an improved process whereby aromatic alcohols and phosphorus halides are reacted at specified temperatures in the presence of amine catalysts thereby providing high yields of substantially pure esters and allowing preparation of selected halogen-containing mono- and di-esters of phosphorus acids wherein halogen is directly bonded to phosphorus having substantially no side reactant contamination. The phosphorus esters are useful as intermediates in the preparation of plasticizers, oil additives and functional fluids.
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