13027-88-8Relevant articles and documents
Mechanistic investigations and secondary coordination sphere effects in the hydration of nitriles with [Ru(η6-arene)Cl2PR 3] complexes
Knapp, Spring Melody M.,Sherbow, Tobias J.,Yelle, Robert B.,Zakharov, Lev N.,Juliette, J. Jerrick,Tyler, David R.
, p. 824 - 834 (2013)
The mechanism of the nitrile-to-amide hydration reaction using [Ru(η6-arene)Cl2(PR3)] complexes as catalysts was investigated (η6-arene = C6H 6, p-cymene, C6Me6; R = NMe2, OMe, OEt, Et, iPr). Experiments showed that the mechanism involves the following general sequence of reactions: substitution of a chloride ligand by the nitrile substrate, intermolecular nucleophilic attack by water to form an amidate intermediate, and dissociation of the resulting amide. The effects of secondary coordination sphere interactions on the rates and yields of the hydration reaction were investigated. Ligands that are capable of acting as hydrogen bond acceptors with the entering water molecule result in faster rates and higher yields than non-hydrogen-bonding ligands. The faster rates are attributable to the H-bonding-facilitated deprotonation of the water as the oxygen of the water bonds to the coordinated nitrile. DFT calculations on the proposed H-bonding intermediates support this interpretation. Most homogeneous catalysts will not hydrate cyanohydrins because of the equilibrium amounts of cyanide that are present in solutions of cyanohydrins; the cyanide poisons the catalyst. Because of its increased catalytic reactivity due to secondary coordination sphere effects, the [Ru(η6-arene)Cl2(P(NMe2) 3)] catalyst gives significant yields of cyanohydrin hydration products with glycolonitrile, lactonitrile, acetone cyanohydrin, and mandelonitrile. A Taft plot showed that an increase in the steric bulk of the nitrile results in a decrease in the hydration rate, and a Hammett plot showed that electron-withdrawing groups facilitate nitrile hydration. The decrease in rate as the size of the cyanohydrin increases is likely due to both increased steric bulk and to the addition of electron-donating groups on the nitrile. The [Ru(η6-arene)Cl2(PR3)] catalysts are initially less susceptible to cyanide poisoning than other homogeneous nitrile hydration catalysts because [Ru(η6-p-cymene)(CN)(Cl)(P(NMe 2)3)] forms in the presence of cyanide. The electron-withdrawing cyanide ligand facilitates nucleophilic attack of water on a coordinated nitrile in this molecule.
Cyanohydrin hydration with [Ru(η6-p-cymene)Cl 2PR3] complexes
Knapp, Spring Melody M.,Sherbow, Tobias J.,Juliette, J. Jerrick,Tyler, David R.
, p. 2941 - 2944 (2012)
The catalytic hydration of cyanohydrins to their corresponding α-hydroxyamides provides a route to industrially useful α-hydroxy amides, α-hydroxy esters, α-hydroxy carboxylic acids, and their acrylic derivatives. However, until now, no homogeneous nitrile hydration catalyst has been capable of complete conversion of cyanohydrins to their corresponding amides because cyanohydrins degrade to produce cyanide, which poisons the catalyst. Because the cyanohydrin degradation is an equilibrium process, it was hypothesized that a faster nitrile hydration catalyst would be capable of hydrating the cyanohydrin before degradation occurs. Secondary coordination sphere effects were used to develop a faster catalyst based on the [Ru(η6-arene)Cl2(PR3)] scaffold. A series of [Ru(η6-p-cymene)Cl2(PR3)] complexes, where R = NMe2, OMe, Et, was synthesized, and their activity toward cyanohydrin hydration was determined. The complex [Ru(η6-p- cymene)Cl2(P(NMe2)3)] is an excellent catalyst, and the unprecedented complete conversion of a cyanohydrin to its corresponding amide using a homogeneous catalyst was achieved with glycolonitrile and lactonitrile.
Hydration of Cyanohydrins by Highly Active Cationic Pt Catalysts: Mechanism and Scope
Li, Chengcheng,Chang, Xiao-Yong,Huo, Luqiong,Tan, Haibo,Xing, Xiangyou,Xu, Chen
, p. 8716 - 8726 (2021/07/26)
Cyanohydrins (α-hydroxy nitriles) are a special type of nitriles that readily decompose into hydrogen cyanide (HCN) and the corresponding carbonyl compounds. Hydration of cyanohydrins that are readily available through cyanation of aldehydes and ketones provides the most straightforward route to valuable α-hydroxyamides. However, due to low stability of cyanohydrins and deactivation of the catalysts by the released HCN, catalytic direct hydration of cyanohydrins still remains largely unsolved. As a general trend, cyanohydrins containing bulkier substituents, such as α,α-diaryl cyanohydrins, degrade more quickly and thus are more difficult to be hydrated. Here, we report development of cationic platinum catalysts that exhibit high reactivity for hydration of various cyanohydrins. Detailed mechanistic investigations for hydration of nitriles by (PμP)Pt(PR2OH)X(OTf) reveal a catalytic cycle involving the formation of a five-membered metallacyclic intermediate and subsequent hydrolysis via attacking on the phosphorus of the secondary phosphine oxide (PR2OH) ligand by H2O. We discovered that Pt catalyst A bearing the electron-rich, appropriately small-bite-angle bisphosphine ligand provides super reactivity for hydration of cyanohydrins. The hydration reactions catalyzed by A proceed at ambient temperatures and occur with a wide variety of cyanohydrins, including the most difficult α,α-diaryl cyanohydrins, with good turnover numbers.
Catalyst, preparation method thereof and preparation method of amide compound
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Paragraph 0142-0146; 0147, (2020/01/12)
The invention relates to a catalyst, a preparation method thereof, and a preparation method for hydrating nitrile groups into amides. The catalyst is used for catalyzing nitrile groups to be hydratedinto amides, and the structural general formula of the catalyst is shown in the specification. In the formula, a plurality of R are respectively and independently ones selected from aromatic groups, heteroaromatic groups and non-aromatic ring groups; a plurality of R are ones respectively and independently selected from linear alkyl groups and alkane aromatic groups; X is one selected from Cl and Br; and L is one selected from OTf, BF4, PF6 and SbF6. The catalyst can catalyze nitrile groups to be hydrated into amides, and the nitrile groups can be catalyzed to be hydrated into amides even at a low temperature (20-80 DEG C); besides, compared with existing common catalysts for catalyzing nitrile groups to be hydrated into amides, the catalyst has the advantages that the equivalent weight of the catalyst can be obviously reduced, and nitrile groups can reach a relatively high conversion rate when the equivalent weight of the catalyst is only 0.01 mol%-0.5 mol%; and meanwhile, the catalyst is wider in application range and can catalyze various nitrile compounds to be hydrated into amide compounds.
Catalytic Transfer Hydration of Cyanohydrins to α-Hydroxyamides
Kanda, Tomoya,Naraoka, Asuka,Naka, Hiroshi
supporting information, p. 825 - 830 (2019/01/14)
We report the palladium(II)-catalyzed transfer hydration of cyanohydrins to α-hydroxyamides by using carboxamides as water donors. This method enables selective hydration of various aldehyde- and ketone-derived cyanohydrins to afford α-mono- and α,α-disubstituted-α-hydroxyamides, respectively, under mild conditions (50 °C, 10 min). The direct conversion of fenofibrate, a drug bearing a benzophenone moiety, into a functionalized α,α-diaryl-α-hydroxyamide was achieved by means of a hydrocyanation-transfer hydration sequence. Preliminary kinetic studies and the synthesis of a site-specifically 18O-labeled α-hydroxyamide demonstrated the carbonyl oxygen transfer from the carboxamide reagent into the α-hydroxyamide product.
Highly Active Platinum Catalysts for Nitrile and Cyanohydrin Hydration: Catalyst Design and Ligand Screening via High-Throughput Techniques
Xing, Xiangyou,Xu, Chen,Chen, Bo,Li, Chengcheng,Virgil, Scott C.,Grubbs, Robert H.
supporting information, p. 17782 - 17789 (2019/01/04)
Nitrile hydration provides access to amides that are indispensable to researchers in chemical and pharmaceutical industries. Prohibiting the use of this venerable reaction, however, are (1) the dearth of biphasic catalysts that can effectively hydrate nitriles at ambient temperatures with high turnover numbers and (2) the unsolved challenge of hydrating cyanohydrins. Herein, we report the design of new "donor-acceptor"-type platinum catalysts by precisely arranging electron-rich and electron-deficient ligands trans to one other, thereby enhancing both the nucleophilicity of the hydroxyl group and the electrophilicity of the nitrile group. Leveraging a high-throughput, automated workflow and evaluating a library of bidentate ligands, we have discovered that commercially available, inexpensive DPPF [1,1′-ferrocenendiyl-bis(diphenylphosphine)] provides superior reactivity. The corresponding "donor-acceptor"-type catalyst 2a is readily prepared from (DPPF)PtCl2, PMe2OH, and AgOTf. The enhanced activity of 2a permits the hydration of a wide range of nitriles and cyanohydrins to proceed at 40 °C with excellent turnover numbers. Rational reevaluation of the ligand structure has led to the discovery of modified catalyst 2c, harboring the more electron-rich 1,1′-bis[bis(5-methyl-2-furanyl)phosphino] ferrocene ligand, which demonstrates the highest activity toward hydration of nitriles and cyanohydrins at room temperature. Finally, the correlation between the electron-donating ability of the phosphine ligands with catalyst efficiencies of 2a, 2c, 2d, and 2e in the hydration of nitrile 7 are examined, and the results support the "donor-acceptor" hypothesis.
METHOD FOR PRODUCING A-HYDROXYISOBUTYRIC ACID AMIDE AND REACTOR
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Paragraph 0151; 0152, (2016/06/13)
The present invention provides a method for producing α-hydroxyisobutyric acid amide by hydration of acetone cyanohydrin under the presence of a catalyst composed mainly of manganese oxide using a reactor in which at least two reaction regions are connected in series, the method being characterized by comprising: a step (B) of cyclically supplying at least a portion of a reaction liquid withdrawn from at least one reaction region to a first reaction region (I) in the reactor; and a step (b1) of further cyclically supplying at least a portion of the reaction liquid withdrawn from at least one reaction region to at least one reaction region other than the first reaction region. The method is also characterized in that an oxidizing agent is supplied to at least one reaction region in the reactor.
Investigation of 1,3,5-triaza-7-phosphaadamantane-stabilized silver nanoparticles as catalysts for the hydration of benzonitriles and acetone cyanohydrin
Sherbow, Tobias J.,Downs, Emma L.,Sayler, Richard I.,Razink, Joshua J.,Juliette, J. Jerrick,Tyler, David R.
, p. 3096 - 3104 (2015/02/19)
A straightforward synthesis of water-soluble silver nanoparticles stabilized by PTA (1,3,5-triaza-7-phosphaadamantane, a water-soluble phosphine ligand) ligands was developed. The nanoparticles were thoroughly characterized by ultraviolet-visible spectroscopy, 31P nuclear magnetic resonance spectroscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The effectiveness of the Ag-PTA nanoparticles as catalysts for the hydration of nitriles to amides in water under mild conditions was explored using a series of substituted benzonitriles and cyanohydrins. In comparison to all previously investigated homogeneous catalysts, the Ag-PTA system excels at cyanohydrin hydration, including acetone cyanohydrin hydration. Cyanohydrins are in equilibrium with small amounts of cyanide, and experiments revealed that the Ag-PTA nanoparticles disassemble in the presence of cyanide. The catalyst solution, which is proposed to contain a soluble Ag(CN)n1-ncomplex (with n likely equal to 2), remained unpoisoned even in the presence of 10 equiv of cyanide. It is suggested that no cyanide poisoning occurs because the Ag(I) complex is labile. Overall, the Ag-PTA catalyst system (a) is not poisoned by cyanide, (b) catalyzes hydration reactions under mild conditions (in air and at relatively low temperatures), (c) is easily synthesized from cheap starting materials, and (d) can hydrate heteroaromatics in good yields. The recognition of the importance of labile metal cyanide bonding represents an important step forward in catalyst design for improving the catalytic hydration of acetone cyanohydrin. (Chemical Equation Presented).
Catalytic nitrile hydration with [Ru(η6- p -cymene)Cl 2(PR2R′)] complexes: Secondary coordination sphere effects with phosphine oxide and phosphinite ligands
Knapp, Spring Melody M.,Sherbow, Tobias J.,Yelle, Robert B.,Juliette, J. Jerrick,Tyler, David R.
supporting information, p. 3744 - 3752 (2013/07/26)
The rates of nitrile hydration reactions were investigated using [Ru(η6-p-cymene)Cl2(PR2R′)] complexes as homogeneous catalysts, where PR2R′ = PMe 2(CH2P(O)Me2), PMe2(CH 2CH2P(O)Me2), PPh2(CH 2P(O)Ph2), PPh2(CH2CH 2P(O)Ph2), PMe2OH, P(OEt)2OH. These catalysts were studied because the rate of the nitrile-to-amide hydration reaction was hypothesized to be affected by the position of the hydrogen bond accepting group in the secondary coordination sphere of the catalyst. Experiments showed that the rate of nitrile hydration was fastest when using [Ru(η6-p-cymene)Cl2PMe2OH]: i.e., the catalyst with the hydrogen bond accepting group capable of forming the most stable ring in the transition state of the rate-limiting step. This catalyst is also active at pH 3.5 and at low temperatures - conditions where α-hydroxynitriles (cyanohydrins) produce less cyanide, a known poison for organometallic nitrile hydration catalysts. The [Ru(η6-p-cymene) Cl2PMe2OH] catalyst completely converts the cyanohydrins glycolonitrile and lactonitrile to their corresponding α-hydroxyamides faster than previously investigated catalysts. [Ru(η6-p-cymene) Cl2PMe2OH] is not, however, a good catalyst for acetone cyanohydrin hydration, because it is susceptible to cyanide poisoning. Protecting the -OH group of acetone cyanohydrin was shown to be an effective way to prevent cyanide poisoning, resulting in quantitative hydration of acetone cyanohydrin acetate.
PROCESS FOR PRODUCING ORGANIC CARBOXYLIC ACID AMIDES
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Page/Page column 2-3, (2011/01/12)
The present invention relates to a process for producing organic carboxylic acid amides by nitrile hydrolysis of a nitrile compound at certain temperature and pressure in the presence of a catalyst to produce an organic carboxylic acid amide.
