103-49-1Relevant articles and documents
Reductive amination of aldehydes and ketones with 2-(Tributylamino)- ethoxyborohydride
Mohanazadeh, Farajollah,Forozani, Mehdi,Taheri, Azam
, p. 1187 - 1189 (2007)
A new ionic liquid is presented as a medium and reducing agent for the reductive amination of aldehydes and ketones.
A general approach to mono- and bimetallic organometallic nanoparticles
Mavila, Sudheendran,Rozenberg, Illya,Lemcoff, N. Gabriel
, p. 4196 - 4203 (2014)
A comprehensive methodology to prepare nanometric size organometallic particles (ONPs) containing rhodium(i), iridium(i) and nickel(0) with ROMP-derived polycycloocta-1,5-diene (pCOD) by a controlled single chain collapse mechanism was developed. The polymeric complexes could be produced via direct exchange of the respective labile ligands of metal complexes by the 1,5-hexadiene elements in pCOD, or via in situ reduction of metal ions in the presence of the polymer. These well-defined π-bound polymeric complexes were characterized by UV-Vis spectroscopy, dynamic light scattering (DLS) and size exclusion chromatography (SEC) measurements and the resulting polymer sizes were found to be inversely proportional to the amount of metal added due to concomitant single chain collapse. Moreover, these procedures were readily extended to the synthesis of organobimetallic nanoparticles containing two metals; which could be added in commutative order and specific metal ratios. The embedded metal elements were found to be readily accessible for applications in catalysis, where the close proximity of the catalytic centers led to distinctive reactivity compared to the isolated complexes.
A new method for deprotection of benzothiazolesulfonamides using a thiol and base
Wuts, Peter G. M.,Gu, Rui Lin,Northuis, Jill M.,Thomas, Collette L.
, p. 9155 - 9156 (1998)
Benzothiazolesulfonamides of primary and secondary amines are efficiently cleaved by a nucleophilic aromatic substitution with a thiol and a base such as potassium t-butoxide or diisopropylethyl amine in DMF.
Graphene-supported NiPd alloy nanoparticles: A novel and highly efficient heterogeneous catalyst system for the reductive amination of aldehydes
Ni?anci, Bilal,Ganjehyan, Khadijeh,Metin, ?nder,Da?tan, Arif,T?r?k, Béla
, p. 191 - 197 (2015)
A novel and highly efficient heterogeneous catalytic reductive amination of aldehydes is described. The recently developed graphene supported NiPd alloy nanoparticle (G-NiPd) catalyst using ammonia borane (AB) as a green, stable and safe hydrogen donor was used in a water/methanol mixture (v/v = 2/3) under ambient conditions. The catalytic system was successfully applied in the reductive amination of various substituted aldehydes with amines and the corresponding products were obtained in (up to) 99% yield in 6 h. The G-NiPd catalyst could be recycled up to five times without any significant loss in the product yield.
Triazolylidene-Iridium Complexes with a Pendant Pyridyl Group for Cooperative Metal–Ligand Induced Catalytic Dehydrogenation of Amines
Valencia, Marta,Pereira, Ana,Müller-Bunz, Helge,Belderraín, Tomás R.,Pérez, Pedro J.,Albrecht, Martin
, p. 8901 - 8911 (2017)
Two iridium(III) complexes containing a C,N-bidentate pyridyl-triazolylidene ligand were prepared that are structurally very similar but differ in their pendant substituent. Whereas complex 1 contains a non-coordinating pyridyl unit, complex 2 has a phenyl group on the triazolylidene substituent. The presence of the basic pyridyl unit has distinct effects on the catalytic activity of the complex in the oxidative dehydrogenation of benzylic amines, inducing generally higher rates, higher selectivity towards formation of imines versus secondary amines, and notable quantities of tertiary amines when compared to the phenyl-functionalized analogue. The role of the pyridyl functionality has been elucidated from a set of stoichiometric experiments, which demonstrate hydrogen bonding between the pendant pyridyl unit and the amine protons of the substrate. Such Npyr???H?N interactions are demonstrated by X-ray diffraction analysis, 1H NMR, and IR spectroscopy, and suggest a pathway of substrate bond-activation that involves concerted substrate binding through the Lewis acidic iridium center and the Lewis basic pyridyl site appended to the triazolylidene ligand, in agreement with ligand–metal cooperative substrate activation.
Copper-Catalyzed Enantioselective Addition of Styrene-Derived Nucleophiles to Imines Enabled by Ligand-Controlled Chemoselective Hydrocupration
Yang, Yang,Perry, Ian B.,Buchwald, Stephen L.
, p. 9787 - 9790 (2016)
The copper-catalyzed intermolecular enantioselective addition of styrenes to imines has been achieved under mild conditions at ambient temperature. This process features the use of styrenes as latent carbanion equivalents via the intermediacy of catalytically generated benzylcopper derivatives, providing an effective means for accessing highly enantiomerically enriched amines bearing contiguous stereocenters. Mechanistic studies shed light on the origin of the preferential styrene hydrocupration in the presence of an imine with the Ph-BPE-derived copper catalyst.
Utilization of lithium triethylborohydride as a selective N-acyl deprotecting agent
Tanaka, Hideyuki,Ogasawara, Kunio
, p. 4417 - 4420 (2002)
Lithium triethylborohydride has been found to be a superior and selective reagent for the removal of tertiary N-acyl protecting groups. The reagent selectively removes tertiary amide acyl functionality without affecting secondary amide functionality even when they are present in the same molecule. Some tertiary carbamates may be also removed under the same conditions.
Cobalt-catalyzed transfer hydrogenation of C=O and C=N bonds
Zhang, Guoqi,Hanson, Susan K.
, p. 10151 - 10153 (2013)
An earth-abundant metal cobalt catalyst has been developed for the transfer hydrogenation of ketones, aldehydes, and imines under mild conditions. Experiments are described which provide insights into the mechanism of the transfer hydrogenation reaction. The Royal Society of Chemistry 2013.
Iridium versus Iridium: Nanocluster and Monometallic Catalysts Carrying the Same Ligand Behave Differently
Cano, Israel,Martínez-Prieto, Luis M.,Chaudret, Bruno,van Leeuwen, Piet W. N. M.
, p. 1444 - 1450 (2017)
A specific secondary phosphine oxide (SPO) ligand (tert-butyl(phenyl)phosphine oxide) was employed to generate two iridium catalysts, an Ir–SPO complex and IrNPs (iridium nanoparticles) ligated with SPO ligands, which were compared mutually and with several supported iridium catalysts with the aim to establish the differences in their catalytic properties. The Ir–SPO-based catalysts showed totally different activities and selectivities in the hydrogenation of various substituted aldehydes, in which H2is likely cleaved by a metal–ligand cooperation, that is, the SPO ligand and a neighboring metal centre operate in tandem to activate the hydrogen molecule. In addition, the supported IrNPs behave very differently from both Ir–SPO catalysts. This study exemplifies perfectly the advantages and disadvantages related to the use of the main types of catalysts, and thus the dissimilarities between them.
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Axenrod,Milne
, p. 5775,5781 (1968)
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Protocol for Visible-Light-Promoted Desulfonylation Reactions Utilizing Catalytic Benzimidazolium Aryloxide Betaines and Stoichiometric Hydride Donor Reagents
Hasegawa, Eietsu,Tanaka, Tsukasa,Izumiya, Norihiro,Kiuchi, Takehiro,Ooe, Yuuki,Iwamoto, Hajime,Takizawa, Shin-Ya,Murata, Shigeru
, p. 4344 - 4353 (2020)
An unprecedented photocatalytic system consisting of benzimidazolium aryloxide betaines (BI+-ArO-) and stoichiometric hydride reducing reagents was developed for carrying out desulfonylation reactions of N-sulfonyl-indoles,-amides, and-amines, and α-sulfonyl ketones. Measurements of absorption spectra and cyclic voltammograms as well as density functional theory (DFT) calculations were carried out to gain mechanistic information. In the catalytic system, visible-light-activated benzimidazoline aryloxides (BIH-ArO-), generated in situ by hydride reduction of the corresponding betaines BI+-ArO-, donate both an electron and a hydrogen atom to the substrates. A modified protocol was also developed so that a catalytic quantity of more easily prepared hydroxyaryl benzimidazolines (BIH-ArOH) is used along with a stoichiometric hydride donor to promote the photochemical desulfonylation reactions.
Indium-catalyzed reduction of secondary amides with a hydrosiloxane leading to secondary amines
Sakai, Norio,Takeoka, Masashi,Kumaki, Takayuki,Asano, Hirotaka,Konakahara, Takeo,Ogiwara, Yohei
, p. 6448 - 6451 (2015)
Described herein is that the selective reduction of aromatic/aliphatic secondary amides using a combination of InI3 and TMDS (1,1,3,3-tetramethyldisiloxane), which led to the production of the corresponding secondary amines. This reducing system showed a relatively high tolerance to a variety of functional groups, such as an alkyl, an alkoxy, a halogen, a cyano, an ether, a thioether, a heterocyclic ring, and a terminal alkene group.
Easy microwave assisted deprotection of N-Boc derivatives
Siro, Jorge G.,Martín, Justina,García-Navío, José L.,Remui?an, Modesto J.,Vaquero, Juan J.
, p. 147 - 148 (1998)
A simple and efficient method for the cleavage of tert-butoxycarbonyl amides and amines is described, which takes place on silica gel under microwave irradiation.
Iron-catalyzed Cα-H oxidation of tertiary, aliphatic amines to amides under mild conditions
Legacy, Christopher J.,Wang, Anqi,O'Day, Brian J.,Emmert, Marion H.
, p. 14907 - 14910 (2015)
De novo syntheses of amides often generate stoichiometric amounts of waste. Thus, recent progress in the field has focused on precious metal catalyzed, oxidative protocols to generate such functionalities. However, simple tertiary alkyl amines cannot be used as starting materials in these protocols. The research described herein enables the oxidative synthesis of amides from simple, noncyclic tertiary alkyl amines under synthetically useful, mild conditions through a biologically inspired approach: Fe-catalyzed Cα-H functionalization. Mechanistic investigations provide insight into reaction intermediates and allow the development of a mild Cα-H cyanation method using the same catalyst system. The protocol was further applied to oxidize the drug Lidocaine, demonstrating the potential utility of the developed chemistry for metabolite synthesis. Let′s iron it out! The title reaction enables the oxidative synthesis of amides directly from tertiary, noncyclic alkyl amines under synthetically useful, mild conditions through a biologically inspired approach employing oxidative iron catalysis. Mechanistic studies suggest that hemiaminals are likely intermediates in this reaction and that the catalytic system can be employed for other Cα-H oxidations of amines.
Hydrogenation of CO2, carbonyl and imine substrates catalyzed by [IrH3(PhPNHP)] complex
Ramaraj, Ayyappan,Nethaji, Munirathinam,Jagirdar, Balaji R.
, p. 25 - 34 (2019)
A series of iridium and rhodium complexes [M(COD)(PhPNHP)]Cl {M = Ir (1), Rh (2)}, [MH2Cl(PhPNHP)] {M = Ir (3), Rh (4)} and [IrH3(PhPNHP)] (6) supported by pincer ligand H–N(CH2CH2PPh2)2 {PhPNHP} have been synthesized and characterized. All complexes were isolated in good yields. The iridium trihydride complex [IrH3(PhPNHP)] (6) was found to be an active catalyst for the hydrogenation of CO2 in 1 M aqueous KOH solution. It also acts as a catalyst for the base-free hydrogenation of carbonyl and imine substrates in MeOH. Under similar hydrogenation conditions, 2-cyclohexen-1-one undergoes solvent assisted tandem Michael addition-reduction mediated by bifunctional Lewis-acid-catalyst [IrH3(PhPNHP)] in ROH (R = Me, Et) at room temperature. The complexes 1, 3, 4, and 6 were characterized by X-ray crystallography. Extensive hydrogen bonding interactions N–H?H–Ir (2.15 ?), N–H?Cl (2.370 ?) were noted in the crystal structures of these complexes.
Catalyst-Free and Solvent-Free Facile Hydroboration of Imines
Pandey, Vipin K.,Donthireddy, Siva Nagendra Reddy,Rit, Arnab
, p. 3255 - 3258 (2019)
A facile process for the catalyst-free and solvent-free hydroboration of aromatic as well as heteroaromatic imines is reported. This atom-economic methodology is scalable, compatible with sterically and electronically diverse imines, displaying excellent tolerance towards various functional groups, and works efficiently at ambient temperature in most of the cases, affording secondary amines in good to excellent yield after hydrolysis.
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Hey,Ingold
, p. 66 (1933)
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Hemilabile N-heterocyclic carbene (NHC)-nitrogen-phosphine mediated Ru (II)-catalyzed N-alkylation of aromatic amine with alcohol efficiently
Yu, Xiao-Jun,He, Hai-Yu,Yang, Lei,Fu, Hai-Yan,Zheng, Xue-Li,Chen, Hua,Li, Rui-Xiang
, p. 54 - 57 (2017)
Based on the hemilability, a novel N-heterocyclic carbene (NHC)-nitrogen-phosphine ligand (1) was synthesized, and the combination of it with [Ru(COD)Cl2]n showed the high activity and selectivity with a low Ru loading of 0.1% for the N-alkylation of amine with alcohol. Especially, for these substrates with pyridine backbone, even if the catalyst loading was as low as 0.01%, good yields (81–95%) of the desired products were achieved.
Five-Coordinate Low-Spin {FeNO}7 PNP Pincer Complexes
Pecak, Jan,St?ger, Berthold,Mastalir, Matthias,Veiros, Luis F.,Ferreira, Liliana P.,Pignitter, Marc,Linert, Wolfgang,Kirchner, Karl
, p. 4641 - 4646 (2019)
The synthesis and characterization of air-stable cationic mono nitrosonium Fe(I) PNP pincer complexes of the type [Fe(PNP)(NO)Cl]+ are described. These complexes are obtained via direct nitroslyation of [Fe(PNP)Cl2] with nitric oxide at ambient pressure. On the basis of magnetic and EPR measurements as well as DFT calculations, these compounds were found to adopt a low-spin d7 configuration and feature a nearly linear bound NO ligand suggesting FeINO+ rather than FeIINO? character. X-ray structures of all nitrosonium Fe(I) PNP complexes are presented. Preliminary investigations reveal that [Fe(PNPNH-iPr)(NO)(Cl)]+ efficiently catalyzes the conversion of primary alcohols and aromatic and benzylic amines to yield mono N-alkylated amines in good isolated yields.
Nickel-Catalyzed Hydrophosphonylation and Hydrogenation of Aromatic Nitriles Assisted by Lewis Acid
Islas, Rosa E.,García, Juventino J.
, p. 1337 - 1345 (2019)
In this paper, we describe the catalytic hydrophosphonylation of several aromatic nitriles used to synthesize α-aminophosphonates (α-APs) using commercially available trialkyl phosphites (P(OR)3, R=Et, iPr, Bu,) and simple and inexpensive nickel chloride (NiCl2.6H2O) as the catalytic precursor. The use of triethylborane (Et3B) as a Lewis acid (LA) was mandatory in order to successfully perform H-phosphite moiety incorporation at the CN bond of non-activated benzonitriles (BN) derivatives. Interestingly, when a highly activated BN such as 2,3,4,5,6-pentafluorobenzonitrile (BN-g) was employed, it was possible to perform the reaction in the absence of an LA using milder reaction conditions. Also, we found that using HP(O)(OiPr)2 as a starting material afforded the aminobisphosphonate derivative with better selectivity than using the method involving P(OiPr)3 as the initial reagent. Remarkably, when using HP(O)(OiPr)2 with an excess of Et3B, the reaction's selectivity completely changed to yield N-benzyl- benzylimine (BBI) and 2,4,5-triphenylimidazole.
Improving the industrial feasibility of metal-free hydrogenation catalysts using chemical scavengers
Thomson, Jordan W.,Hatnean, Jillian A.,Hastie, Jeff J.,Pasternak, Andrew,Stephan, Douglas W.,Chase, Preston A.
, p. 1287 - 1292 (2013)
A modified process using inexpensive poison scavengers has been developed that allows for more economical and practical scale-up of metal-free catalytic hydrogenation. The scavengers remove impurities such as water and aldehydes that can hinder catalysis allowing for the use of commercial-grade solvents, substrates and gases. In addition, the scavengers have the unique ability to regenerate poisoned catalysts, allowing for increased turnover numbers and longer catalyst lifetimes. Hydrogenations of unpurified imine substrates proceed with high yield using a variety of metal-free hydrogenation catalysts, demonstrating the general compatibility of this process.
Highly chemoselective reductive amination-coupling by one-pot reaction of aldehydes, HMDS and NaBH4
Azizi, Najmedin,Akbari, Elham,Amiri, Alireza Khejeh,Saidi, Mohammad R.
, p. 6682 - 6684 (2008)
An efficient and highly chemoselective synthesis of symmetrical secondary amines via reductive amination of aldehydes with inexpensive and commercially available HMDS and sodium borohydride in high to quantitative yields is reported.
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Richey,Erickson
, p. 2807 (1972)
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Trichlorosilane-dimethylformamide (Cl3SiH-DMF) as an efficient reducing agent. Reduction of aldehydes and imines and reductive amination of aldehydes under mild conditions using hypervalent hydridosilicates
Kobayashi, Shu,Yasuda, Masaru,Hachiya, Iwao
, p. 407 - 408 (1996)
Trichlorosilane-dimethylformamide (Cl3SiH-DMF) was found to be an effective reducing agent for reduction of aldehydes to alcohols, imines to amines, and also reductive amination of aldehydes. Hypervalent silicates are active species, which enable efficient reduction under mild conditions.
Visible Light and Hydroxynaphthylbenzimidazoline Promoted Transition-Metal-Catalyst-Free Desulfonylation of N-Sulfonylamides and N-Sulfonylamines
Hasegawa, Eietsu,Nagakura, Yuto,Izumiya, Norihiro,Matsumoto, Keisuke,Tanaka, Tsukasa,Miura, Tomoaki,Ikoma, Tadaaki,Iwamoto, Hajime,Wakamatsu, Kan
, p. 10813 - 10825 (2018)
A visible light promoted process for desulfonylation of N-sulfonylamides and -amines has been developed, in which 1,3-dimethyl-2-hydroxynaphthylbenzimidazoline (HONap-BIH) serves as a light absorbing, electron and hydrogen atom donor, and a household white light-emitting diode serves as a light source. The process transforms various N-sulfonylamide and -amine substrates to desulfonylated products in moderate to excellent yields. The observation that the fluorescence of 1-methyl-2-naphthoxy anion is efficiently quenched by the substrates suggests that the mechanism for the photoinduced desulfonylation reaction begins with photoexcitation of the naphthoxide chromophore in HONap-BIH, which generates an excited species via intramolecular proton transfer between the HONap and BIH moieties. This process triggers single electron transfer to the substrate, which promotes loss of the sulfonyl group to form the free amide or amine. The results of studies employing radical probe substrates as well as DFT calculations suggest that selective nitrogen-sulfur bond cleavage of the substrate radical anion generates either a pair of an amide or amine anion and a sulfonyl radical or that of an amidyl or aminyl radical and sulfinate anion, depending on the nature of the N-substituent on the substrate. An intermolecular version of this protocol, in which 1-methyl-2-naphthol and 1,3-dimethyl-2-phenylbenzimidazoline are used concomitantly, was also examined.
Tandem Fe/Zn or Fe/In Catalysis for the Selective Synthesis of Primary and Secondary Amines?via Selective Reduction of Primary Amides
Darcel, Christophe,Wu, Jiajun
, (2022/03/18)
Tandem iron/zinc or iron/indium-catalysed reductions of various primary amides to amines under hydrosilylation conditions are reported under visible light activation. By a simple modification of the nature of the co-catalyst (Zn(OTf)2 vs In(OTf)3), Fe(CO)4(IMes) can promote the highly chemoselective reduction of primary amides into primary amines (21 examples, up to 93 % isolated yields) and secondary amines (8 examples, up to 51 % isolated yields), respectively. Notably, both benzamide and alkanamide derivatives can be reduced.
Chemoselective transfer hydrogenation of nitriles to secondary amines with nickel(II) catalysts
Vermaak, Vincent,Vosloo, Hermanus C.M.,Swarts, Andrew J.
, (2021/07/25)
Herein we report the selective transfer hydrogenation (TH) of nitriles to secondary (2°) amines with simple Ni(II)-catalysts using ammonia borane (AB) as a source of hydrogen (H2). A bis(pyrazolylmethyl)pyridine (L1) or ethylenediamine (L4) ligated Ni(II) pre-catalyst, created in situ, could hydrogenate several aromatic- and aliphatic nitriles in full conversions and isolated yields of up to 88% under ambient temperature and in very short reaction times. Deuterium labelling experiments illustrated the incorporation of a proton on the nitrogen and hydride on the α-carbon of dibenzylamine. Using α-picoline borane, containing no dissociable protons, assisted with the postulation of a two-step TH mechanism of benzonitrile. AB was subjected to dehydrogenation and it was observed that a maximum of 2.96 equivalents of H2 gas could be generated from NiCl2?6H2O/L1.
