- Catalyst-free dynamic exchange of aromatic Schiff base bonds and its application to self-healing and remolding of crosslinked polymers
-
The present work reveals that catalyst-free dynamic reversible exchange of aromatic Schiff base bonds is enabled at room temperature. Attachment of aryl groups to both nitrogen and carbon atoms of carbon-nitrogen double bonds is a critical structural factor that contributes to the dynamic characteristics and complete reaction between aromatic aldehyde and aromatic amine. The exchange mechanism is studied by model compounds, and free radical intermediates are found to be involved in the non-equilibrium stage of the exchange reaction. By taking advantage of the dynamic equilibrium of aromatic Schiff base bonds, infusible and insoluble crosslinked polyacrylate is self-healed and reprocessed through rearrangement of macromolecular networks. The reprocessed polymer is still self-healable. Either the self-healing or reprocessing is completed in air without heating. Considering that Schiff base polymers have shown diverse properties and stimulus-response behaviors, activation of the dynamic exchange of the inherent Schiff base bonds would result in a series of novel functionalities. More interestingly, traditional crosslinked polymers might thus be provided with a facile way of being smarter.
- Lei, Zhou Qiao,Xie, Pu,Rong, Min Zhi,Zhang, Ming Qiu
-
-
Read Online
- One-pot imine synthesis from benzylic alcohols and nitrobenzene on CdS-sensitized TiO2 photocatalysts: Effects of the electric nature of the substituent and solvents on the photocatalytic activity
-
A new strategy for the one-pot synthesis of imines from several benzylic alcohols with such substituted groups as CF3, Cl, CH3, OCH3 and nitrobenzene were studied on the CdS-sensitized TiO2 (CdS-TiO2) photocatalyst under visible-light irradiation (λ > 420 nm) at room temperature. It was observed that the photocatalytic activities strongly depended on the electric nature of the substituted groups in the benzylic alcohols, following the Hammett rules. The photocatalytic activities can be explained by the photocurrent efficiency and a shift of the flatband potentials of the CdS photoelectrode depending on the degree of electron-donacity of the substituted groups. Moreover, the solvent effects on the yields of imines were also investigated in non-polar solvents (toluene, cyclohexane) and polar solvents (ethanol, acetonitrile). It was observed that the non-polar solvents caused higher photocatalytic activities for the synthesis of several imines than polar solvents due to the efficient condensation of photo-formed benzaldehyde and aniline.
- Nakai, Yuta,Azuma, Masashi,Muraoka, Masahiro,Kobayashi, Hisayoshi,Higashimoto, Shinya
-
-
Read Online
- Stereoselective synthesis of new β-lactams from the main functional group of indomethacin
-
New β-lactams were synthesized in moderate yields from indomethacin, which is currently used as a drug to relieve pain such as arthritis, muscle and bone damage. The reaction was carried out by [2 + 2] cycloaddition of the in situ formed indomethacinyl ke
- Amiri, Mojgan,Islami, Mohammad Reza,Mortazavi, Zahra Fahimeh al-Sadat
-
-
- Tandem imine formationviaauto-hydrogen transfer from alcohols to nitro compounds catalyzed by a nanomagnetically recyclable copper catalyst under solvent-free conditions
-
A direct imination reaction was developed by tandem reaction of alcohols and nitro compounds in the presence of Cu-isatin Schiff base-γ-Fe2O3as a nanomagnetically recyclable catalyst under solvent-free conditions. By this method, various imines were prepared in good to high yields from one-pot reaction of various alcohols (primary aromatic and aliphatic) and nitro compounds (aromatic and aliphatic)viaan auto-hydrogen transfer reaction. Use of an inexpensive and easily reusable catalyst, without requiring any additives or excess amounts of benzyl alcohol as the reaction solvent are the other advantages of this method. This catalytic system has the merits of cost effectiveness, environmental benignity, excellent recyclability and good reproducibility.
- Derakhshan, Seyed Ruhollah,Hosseini Moghadam, Hadis,Sansano, José Miguel,Sobhani, Sara
-
p. 19121 - 19127
(2021/06/03)
-
- Direct synthesis of imines from nitro compounds and biomass-derived carbonyl compounds over nitrogen-doped carbon material supported Ni nanoparticles
-
The selective synthesis of imines from biomass-derived chemicals over heterogeneous non-noble metal catalysts is of great importance for organic transformation. Herein, non-noble heterogeneous nitrogen-doped carbon supported Ni catalysts (abbreviated as Ni/CN-MgO-T, whereTrepresents the pyrolysis temperature) have been facilely prepared from the simple pyrolysis of Ni precursors and biomass, and Ni/CN-MgO-600 with the smallest size of Ni nanoparticles demonstrated the highest catalytic activity. The reductive coupling of nitroarenes and carbonyl compounds could be performed under mild conditions (80 °C, and 10 bar H2), affording structurally-diverse imines with high to excellent yields (84.2-98.1%). Thanks to the mild reaction conditions, the developed method showed good tolerance to other functional groups such as nitriles, halogen and vinyl groups.
- Li, Bo,Wang, Yanxin,Chi, Quan,Yuan, Ziliang,Liu, Bing,Zhang, Zehui
-
p. 4464 - 4471
(2021/03/15)
-
- Highly chemoselective synthesis of imine over Co/Zn bimetallic MOFs derived Co3ZnC-ZnO embed in carbon nanosheet catalyst
-
One-pot direct synthesis of imines via reductive amination of nitroarenes with aromatic aldehydes remains a great challenge due in part to its over-hydrogenation of imines to secondary amines. Herein, a novel Co3ZnC and ZnO supported on N-doped carbon nanosheet catalyst with the thickness of ca. 5.0 nm was fabricated through the direct pyrolysis of a Co/Zn bimetallic MOFs at 500 °C (named as Co3ZnC-ZnO/NC-500). Surprisingly, the developed Co3ZnC-ZnO/NC-500 catalyst delivers 99.9 % conversion of nitrobenzene and 98.5 % selectivity to N-benzylideneaniline in one-pot reductive amination of nitrobenzene with benzaldehyde. Various characterizations (including as SEM, XRD, TEM, AFM, XPS, Raman and N2 adsorption–desorption) have revealed that the generated small size of Co3ZnC alloy, abundant structural defects, larger specific surface area (105.5 m2·g?1) as well as more basic sites are responsible for the outstanding catalytic activity of Co3ZnC-ZnO/NC-500 catalyst for tandem reaction. Moreover, the Co3ZnC-ZnO/NC-500 catalyst exhibits high stability during the recycling experiments without the loss of its catalytic activity. Notably, the results of contrast experiments have demonstrated that the intentional introduction of ZnO in Co3ZnC-ZnO/NC-500 catalyst plays a key role in the selectivity to N-benzylideneaniline in the tandem reaction. This study provides a new guideline for designing tandem catalysts with high selectivity.
- Li, Guangming,Li, Jingfang,Li, Weizuo,Li, Xuewei,Mao, Guijie,She, Wei,Wang, Jing
-
-
- Au(I) Catalyzed Synthesis of Densely Substituted Pyrazolines and Dihydropyridines via Sequential Aza-Enyne Metathesis/6π-Electrocyclization
-
A gold(I) autotandem catalysis protocol is reported for the de novo synthesis of densely substituted pyrazolines and dihydropyridines from the corresponding imine derivatives in a highly regioselective fashion via a one-pot aza-enyne metathesis/6π-electrocyclization sequence. The substituents on the nitrogen atom of the imine perfectly control the reaction pathways from the pivotal 1-azabutadiene intermediate; thus, carbazates were converted into pyrazolines via 6π-electrocyclization of α,β-unsaturated hydrazones, while aryl imines provided dihydropyridines via 6π-electrocyclization of 3-azahexatrienes.
- Sugimoto, Kenji,Kosuge, Shuto,Sugita, Takae,Miura, Yuka,Tsuge, Kiyoshi,Matsuya, Yuji
-
supporting information
p. 3981 - 3985
(2021/05/26)
-
- Visible-Light-Induced Cycloaddition of α-Ketoacylsilanes with Imines: Facile Access to β-Lactams
-
We report the synthesis of β-lactams from α-ketoacylsilanes and imines, which proceeds via a formal [2+2] photochemical cycloaddition with in situ generation of siloxyketene. This mild and operationally simple reaction proceeds in an atom-economic fashion with broad substrate scope, including aldimines, ketimines, hydrazones, and fused nitrogen heterocycles, affording a variety of important β-lactams with satisfactory diastereoselectivities in most cases. This reaction also features good functional-group tolerance, facile scalability and product diversification. Experimental and computational studies suggest that α-ketoacylsilanes can serve as photochemical precursors by engaging in a 1,3 silicon shift to the distal carbonyl group.
- Ye, Jian-Heng,Bellotti, Peter,Paulisch, Tiffany O.,Daniliuc, Constantin G.,Glorius, Frank
-
supporting information
p. 13671 - 13676
(2021/05/11)
-
- Aza-peterson olefinations: Rapid synthesis of (E)-alkenes
-
An aza-Peterson olefination methodology to access 1,3-dienes and stilbene derivatives from the corresponding allyl- or benzyltrimethylsilane is described. Silanes can be deprotonated using Schlosser's base and added to N -phenyl imines or ketones to directly give the desired products in high yields.
- Britten, Thomas K.,Basson, Ashley J.,Roberts, Dean D.,McLaughlin, Mark G.
-
p. 3535 - 3544
(2021/06/03)
-
- Rhodium catalyzed multicomponent dehydrogenative annulation: one-step construction of isoindole derivatives
-
A strategy for one-pot synthesis of isoindoles is describedviaa catalytic multicomponent dehydrogenative annulation of diarylimines, vinyl ketones and simple amines. In the presence of a rhodium catalyst and Cu oxidant, four C-H and two N-H bonds are activated along with the formation of one new C-C and two new C-N bonds, leading to a series of isoindole derivatives in good to very high isolated yields.
- Cheng, Biao,Lyu, Hairong,Quan, Yangjian,Xie, Zuowei
-
supporting information
p. 7930 - 7933
(2021/08/17)
-
- Photocatalytic one-pot multidirectional N-alkylation over Pt/D-TiO2/Ti3C2: Ti3C2-based short-range directional charge transmission
-
Visible-light-induced one-pot, multistep, and chemoselectivity adjustable reactions highlight the economical, sustainable, and green process. Herein, we report Pt nanoparticles dispersed on S and N co-doped titanium dioxide/titanium carbide (MXene) (3%Pt/
- Jiang, Heyan,Sheng, Meilin,Li, Yue,Kong, Shuzhen,Bian, Fengxia
-
-
- Redox-Neutral Imination of Alcohol with Azide: A Sustainable Alternative to the Staudinger/Aza-Wittig Reaction
-
The traditional Staudinger/aza-Wittig reaction represents one of the most powerful tools for imine formation. However, for this multistep procedure, the sacrificial phosphine has to be used, resulting in difficulties in the purification process and waste disposal at the same time. Here, we report a redox-neutral azide-alcohol imination methodology enabled by a base-metal nickel PN3 pincer catalyst. The one-step, waste-free, and high atom-economical features highlight its advantages further. Moreover, mechanistic insight suggests a non-metal-ligand cooperation pathway based on the observation of an intermediate and density functional theory calculations.
- Li, Huaifeng,Lupp, Daniel,Das, Pradip K.,Yang, Li,Gon?alves, Théo P.,Huang, Mei-Hui,El Hajoui, Marwa,Liang, Lan-Chang,Huang, Kuo-Wei
-
p. 4071 - 4076
(2021/04/12)
-
- Fe2Mn(μ3-O)(COO)6 Cluster Based Stable MOF for Oxidative Coupling of Amines via Heterometallic Synergy
-
The direct catalytic oxidative coupling of amines is one of the attracting methods for the synthesis of a variety of pharmaceutical or industrial needed imines. Numerous earth-abundant manganese based salts, oxides, and complexes have been applied in this reaction. However, these compounds suffered from difficult separation, large catalyst loading, complicated reactivation or indeterminate activity. Considering the facts that metal-organic frameworks (MOFs) with crystalline structure, precise composition, and enormous surface area have superior performance in heterogeneous catalytic reactions, herein, we introduced Mn into [Fe3(μ3-O)(CH3COO)6], one of the precursors for the preparation of stable MOFs, and got [Fe2Mn(μ3-O)(CH3COO)6] cluster. After ligand replacement with biphenyl-3,4’,5-tricarboxylic acid (BPTC), heterometallic cluster-based [Fe2Mn(μ3-O)(BPTC)2(DMF)2(H2O)] (1) was obtained. As expected, 1 is stable and able to catalyze the homo- or cross-coupling of amines effectively and selectively with 0.9 mol% catalyst loading at room temperature. Control experiments indicated that the catalytic activity of 1 mainly stems from Mn sites and that Fe synergistically contributes to the stability. Additionally, 1 is recyclable and can be reused easily for at least 8 runs without obvious decrease in catalytic ability. To our knowledge, 1 should be the first heterometallic cluster-based MOF with defined structure suitable for the synthesis of diverse imines from oxidative coupling of amines under mild conditions, which may shed light on the easy preparation of effective heterogeneous catalysts for organic synthesis.
- Wang, Ying-Xia,Wang, Hui-Min,Meng, Pan,Song, Dong-Xia,Qi, Zhikai,Zhang, Xian-Ming
-
p. 2983 - 2989
(2021/08/30)
-
- Ru(II)-NHC catalysed N-Alkylation of amines with alcohols under solvent-free conditions
-
The reaction of [RuCl2(p-cymene)]2 with in situ prepared Ag-N-heterocyclic carbene (NHC) complexes yields a series of [RuCl2(p-cymene)(NHC)] complexes (2). All of the complexes have been characterised by elemental analysis, and 1H NMR and 13C NMR spectroscopies. These complexes have been tested for the N-alkylation of aromatic amines with arylmethyl alcohols under neat conditions in the presence of KOtBu at 120 °C. Compounds (2) are stable and have high catalytic/selective activity for the N-alkylation reactions of primary amines to afford secondary amines.
- Karaca, Emine ?zge,Dehimat, Zieneb Imene,Ya?ar, Sedat,Gürbüz, Nevin,Tebbani, Dahmane,?etinkaya, Bekir,?zdemir, ?smail
-
-
- Half-sandwich Ru(ii) arene complexes bearing benzimidazole ligands for theN-alkylation reaction of aniline with alcohols in a solvent-free medium
-
In this article, the directN-alkylation reactions of amines with alcohol derivatives using the borrowing hydrogen methodology have been investigated. For this purpose, a new series of half-sandwich ruthenium(ii) complexes bearing N-coordinated benzimidazole complexes have been synthesized and fully characterized by FT-IR,1H NMR and13C NMR spectroscopies. Additionally, the structures of the complexes2a-2ehave been characterized by X-ray crystallography. All new complexes were investigated for their catalytic activities in the alkylation reaction of amines with alcohol derivatives. It was found that alkylation reactions in a solvent-free medium are efficient and selective.
- ?i?ek, Metin,Gürbüz, Nevin,?zdemir, Nam?k,?zdemir, ?smail,?spir, Esin
-
p. 11075 - 11085
(2021/07/02)
-
- Amino-functionalized zirconium and cerium MOFs: Catalysts for visible light induced aerobic oxidation of benzylic alcohols and microwaves assisted N-Alkylation of amines
-
Herein we report that mixed zirconium-cerium-MOFs with amino-functionalized linkers (2-amino-1,4-benzenedicarboxylate, BDC-NH2, and 4-aminonaphthalene-2,6-dicarboxylate, NDC-NH2) act as effective non-noble-metal-based heterogeneous c
- Iglesias, Marta,Pintado-Sierra, Mercedes,Rasero-Almansa, Antonia,Sánchez, Félix,Valverde-González, Antonio
-
-
- Application of a reusable Co-based nanocatalyst in alcohol dehydrogenative coupling strategy: Synthesis of quinoxaline and imine scaffolds
-
A nitrogen doped carbon supported cobalt catalyzed efficient synthesis of imines and quinoxaline motifs is reported. Co(OAc)2-Phen/Carbon-800 (Co-phen/C-800) showed the superior reactivity compared to other materials prepared at different temperature, in the synthesis of quinoxalines by the coupling between diamines and diols. Moreover, applying the transfer hydrogenation and acceptorless dehydrogenative coupling strategy, imines and quinoxaline derivatives were synthesized from the nitro compounds. The practical applicability of this protocol was demonstrated by the gram-scale synthesis and the reusability of the catalyst upto 8th cycle. Furthermore, several kinetic experiments were carried out to realize the probable mechanism.
- Panja, Dibyajyoti,Paul, Bhaskar,Balasubramaniam, Bhuvaneshwari,Gupta, Raju K.,Kundu, Sabuj
-
-
- Rational Design of Cobalt-Platinum Alloy Decorated Cobalt Nanoparticles for One-Pot Synthesis of Imines from Nitroarenes and Aldehydes
-
Developing high-performance heterogeneous catalysts for one-pot reductive amination reactions is critically important for pharmaceutical and agrochemical synthetic industries. In this work, N-doped carbon nanotubes supported CoPt alloy decorated Co nanoparticles (NPs) are successfully fabricated. As a consequence, the resultant catalyst exhibits desirable activity, selectivity and stability toward the one-pot synthesis of imines. More importantly, the extensive experimental studies and density function theory (DFT) calculations results reveal that the high catalytic activity of the catalyst is mainly due to the co-existence of CoPt alloy NPs and Co NPs with Co?Nx active sites. The high selectivity of imines could be ascribed to the following aspects: (1) competitively preferred adsorption of nitroarenes to avoid side-hydrogenation of aldehydes; (2) weakened adsorption of imines to minimize its over-hydrogenation. This work may provide a promising direction and strategy to design high-performance reductive amination catalysts for industrial applications.
- Gong, Wanbing,Han, Miaomiao,Chen, Chun,Lin, Yue,Wang, Guozhong,Zhang, Haimin,Zhao, Huijun
-
p. 5948 - 5958
(2020/10/02)
-
- Unlocking the direct photocatalytic difluoromethylation of CN bonds
-
The current study presents a direct CF2H radical addition to CN bonds predicated on the photocatalytic activation of commercially available zinc difluoromethanesulfinate. The mild conditions in place lead to impressive structural diversity, as quinoxalinones and dibenzazepines, among others, are successfully functionalized.
- Alemán, José,Garrido-Castro, Alberto F.,Gini, Andrea,Maestro, M. Carmen
-
supporting information
p. 3769 - 3772
(2020/04/10)
-
- Cross dehydrogenative coupling strategy for allylation of benzylanilines promoted by DDQ
-
A cross dehydrogenative coupling strategy for allylation of benzylanilines promoted by DDQ is reported, which uses nonmetallic quinone DDQ as an oxidant in the allylation of N-benzylanilines under mild conditions. C–C bond with high selectivity and activity was constructed in this reaction and homoallylic amines were obtained with yields of up to 99%.
- Xiong, Ruimei,Hussain, Muhammad Ijaz,Liu, Qing,Xia, Wen,Xiong, Yan
-
supporting information
(2019/12/11)
-
- Tunable Synthesis of α-Amino Boronic Esters from Available Aldehydes and Amines through Sequential One-Pot Dehydration and Copper-Catalyzed Borylacylation
-
Copper-catalyzed multicomponent borylacylation of imines with acid chlorides and bis(pinacolato)diboron was developed for the preparation of synthetically useful and pharmacologically relevant α-amino boronic acid derivatives. Starting from a range of acid chlorides and imines with aryl, heteroaryl, and alkyl substituents, most of these ligand-free reactions proceeded smoothly at room temperature in moderate to good yields. Furthermore, a facile and convenient one-pot, multistep access to the direct synthesis of α-amino boronic acid derivatives from available aldehydes and amines was also developed.
- Xia, Qi,Chang, Hua-Rong,Li, Juan,Wang, Jia-Yi,Peng, Yan-Qing,Song, Gong-Hua
-
p. 2716 - 2724
(2020/01/31)
-
- Retraction: Harnessing Thiol as a Benzyl Reagent for Photocatalytic Reductive Benzylation of Imines (Organic Letters DOI: 10.1021/2Facs.orglett.0c00065)
-
The authors retract this article after finding in subsequent studies that the quality of the purchased catalysts has a notable impact on the reproducibility of the results. Accordingly, the authors note that additional work is necessary to understand the
- Zhang, Jinghui,Zhang, Muliang
-
supporting information
p. 2112 - 2112
(2020/02/15)
-
- Diethylsilane as a Powerful Reagent in Au Nanoparticle-Catalyzed Reductive Transformations
-
Diethylsilane (Et2SiH2), a simple and readily available dihydrosilane, that exhibits superior reactivity, as compared to monohydrosilanes, in a series of reductive transformations catalyzed by recyclable and reusable Au nanoparticles (1 mol-%) supported on TiO2. It reduces aldehydes or ketones almost instantaneously at ambient conditions. It can be used in a one pot rapid reductive amination procedure, in which premixing of aldehyde and amine is required prior to the addition of the reducing agent and the catalyst, even in a protic solvent. An unprecedented method for the synthesis of N-arylisoindolines is also shown in the reductive amination between o-phthalaldehyde and anilines. In this transformation, it is proposed that the intermediate N,2-diphenylisoindolin-1-imines are reduced stepwise to the isoindolines. Finally, Et2SiH2 readily reduces amides into amines in excellent yields and shorter reaction times relative to previously known analogous nano Au(0)-catalyzed protocols.
- Louka, Anastasia,Kidonakis, Marios,Saridakis, Iakovos,Zantioti-Chatzouda, Elisavet-Maria,Stratakis, Manolis
-
p. 3508 - 3514
(2020/06/02)
-
- Cu/Ni-doped sulfated zirconium oxide immobilized on CdFe2O4 NPs: a cheap, sustainable and magnetically recyclable inorgano-catalyst for the efficient preparation of α-aminonitriles in aqueous media
-
Abstract: A new multifunctional bimetallic nanocatalyst was prepared by immobilization of Cu/Ni-doped sulfated zirconium oxide on magnetic cadmium ferrite (CdFe2O4@SiO2@ZrO2/SO42?/Cu/Ni) and used as an efficient recyclable catalyst for one-pot as well as stepwise preparation of α-aminonitriles under mild conditions. The magnetic nanocatalyst was characterized by FTIR, TGA, VSM, XRD, EDX, FE-SEM, and TEM analyses. Also, the surface acidity of the catalyst was measured by pyridine adsorption assay. The catalyst possesses various active sites which could catalyst a variety of aromatic and aliphatic aldehydes to the corresponding α-amionitriles under moderate to high yields in the presence of aniline. Furthermore, transformation of ketones to the desired α-amionitriles and some bis-aminonitriles was also performed by this method. The catalyst could be readily recovered from the reaction mixture and reused for several times without significant loss of activity. Graphic abstract: A general and efficient method has been developed for transformation of a variety of aliphatic, aromatic aldehydes and ketones to the corresponding α-aminonitriles using a multifunctional recyclable CdFe2O4@SiO2@ZrO2/SO42?/Cu/Ni nanocatalyst.[Figure not available: see fulltext.]
- Nasseri, Mohammad Ali,Ramezani-Moghadam, Simin,Kazemnejadi, Milad,Allahresani, Ali
-
p. 4233 - 4256
(2020/07/08)
-
- Catalyst- And solvent-free efficient access to: N -alkylated amines via reductive amination using HBpin
-
A sustainable approach which works under catalyst- and solvent-free conditions for the synthesis of structurally diverse secondary amines has been uncovered. This one-pot protocol works efficiently at room temperature and is compatible with a wide range of sterically and electronically diverse aldehydes and primary amines. Notably, this simple process offers scalability, excellent functional group tolerance, chemoselectivity, and is also effective at the synthesis of biologically relevant molecules. This journal is
- Bauri, Somnath,Pandey, Vipin K.,Rit, Arnab
-
supporting information
p. 3853 - 3857
(2020/07/27)
-
- Homogeneous cobalt-catalyzed deoxygenative hydrogenation of amides to amines
-
The first general and efficient cobalt-catalyzed deoxygenative hydrogenation of amides to amines is presented. The optimal catalytic system based on a combination of [Co(NTf2)2] and (p-anisyl)triphos (L3) in the presence of [Me3SiOTf] as acidic co-catalyst facilitates the direct hydrogenation of a broad range of amides to the corresponding amines under mild conditions. A set of control experiments indicate that, after the initial reduction of the amide carboxylic group to the well-known hemiaminal intermediate, the reaction mainly proceeds through C-O bond cleavage though other pathways might be also involved to a minor extent. This journal is
- Papa, Veronica,Cabrero-Antonino, Jose R.,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
-
p. 6116 - 6128
(2020/11/03)
-
- A Versatile Approach to Dynamic Amide Bond Formation with Imine Nucleophiles
-
Dynamic covalent chemistry has rapidly become an important approach to access supramolecular structures. While the products generated in these reactions are held together by covalent bonds, the reversible nature of the transformations can limit the utility of many these systems in creating robust materials. We describe herein a method to form stable and commonly employed amide bonds by exploiting the reversible coupling of imines and acyl chlorides. The reaction employs easily accessible reagents, is dynamic under ambient conditions, without catalysts, and can be trapped with simple hydrolysis. This offers an approach to create broad families of amide products under thermodynamic control, including the selective formation of amide macrocycles or polymers.
- Arndtsen, Bruce A.,Erguven, Huseyin,Keyzer, Evan N.
-
-
- One-pot imine synthesis from methylarenes and anilines under air over heterogeneous Cu oxide-modified CeO2catalyst
-
Cu oxide-modified CeO2 (CuOx-CeO2) with 2 wtpercent Cu loading amount was the most effective and reusable heterogeneous catalyst for selective one-pot imine synthesis from methylarenes and anilines via direct oxidation of the sp3 C-H bond in the methylare
- Tamura, Masazumi,Li, Yingai,Tomishige, Keiichi
-
supporting information
p. 7337 - 7340
(2020/07/23)
-
- NHC-assisted Ni(II)-catalyzed acceptorless dehydronation of amines and secondary alcohols
-
A novel catalytic system including NiCl2-NHC ligand precursor has been developed for the preparation of imines from amines and ketones from alcohols. Owing to the acceptorless dehydrogenation pathway for this reaction, the hydrogen gas is liberated as a by-product. The active catalyst is generated in situ by the reaction of nickel (II) chloride, bis (imidazolium) chlorides and potassium tert-butoxide. The products were obtained in good to excellent yields and a wide variety of amines and ketones were applied successfully in this protocol.
- Takallou, Ahmad,Habibi, Azizollah,Halimehjan, Azim Ziyaei,Balalaie, Saeed
-
-
- A Cu-BTC metal-organic framework (MOF) as an efficient heterogeneous catalyst for the aerobic oxidative synthesis of imines from primary amines under solvent free conditions
-
A Cu-BTC (MOF-199) [copper(ii)-benzene-1,3,5-tricarboxylate] catalyst has been synthesized and evaluated for imine synthesis from amine compounds under neat conditions. The performance of the Cu-BTC MOF was significantly higher than that of the CuO supported on Al2O3, TiO2 and SiO2 catalysts. The role of surface Lewis acid sites on the catalyst in the formation of imine products was illustrated by the pyridine-IR studies. The recovered Cu-BTC catalyst demonstrated consistent activity for five cycles under similar experimental conditions. The physicochemical properties of the catalysts were analyzed by XRD, BET-SA, FT-IR, UV-DRS, SEM, TEM, XPS and pyridine adsorbed DRIFT spectroscopy.
- Venu, Boosa,Shirisha, Varimalla,Vishali, Bilakanti,Naresh, Gutta,Kishore, Ramineni,Sreedhar, Inkollu,Venugopal, Akula
-
supporting information
p. 5972 - 5979
(2020/04/27)
-
- Uniform Cu/chitosan beads as a green and reusable catalyst for facile synthesis of iminesviaoxidative coupling reaction
-
A nonprecious metal and biopolymer-based catalyst, Cu/chitosan beads, has been successfully prepared by using a software-controlled flow system. Uniform, spherical Cu/chitosan beads can be obtained with diameters in millimeter-scale and narrow size distribution (0.78 ± 0.04 mm). The size and morphology of the Cu/chitosan beads are reproducible due to high precision of the flow rate. In addition, the application of the Cu/chitosan beads as a green and reusable catalyst has been demonstrated using a convenient and efficient protocol for the direct synthesis of iminesviathe oxidative self- and cross-coupling of amines (24 examples) with moderate to excellent yields. Importantly, the beads are stable and could be reused more than ten times without loss of the catalytic performance. Furthermore, because of the bead morphology, the Cu/chitosan catalyst has greatly simplified recycling and workup procedures.
- Bunchuay, Thanthapatra,Chantiwas, Rattikan,Chutimasakul, Threeraphat,Intanin, Apichai,Na Nakhonpanom, Pakamon,Tantirungrotechai, Jonggol,Tirdtrakool, Warinda
-
p. 21009 - 21018
(2020/06/22)
-
- Active ruthenium(II)-NHC complexes for alkylation of amines with alcohols using solvent-free conditions
-
A series of new ruthenium(II) complexes bearing N-heterocyclic carbene ligands with benzylic groups were prepared by transmetallation reactions between silver(I) N-heterocyclic carbene complexes and [RuCl2(p-cymene)]2. All of the obtained complexes were characterized by FT-IR, 1H NMR and 13C NMR spectroscopy, and the molecular structure of compound 3c was also determined by X-ray crystallography. These ruthenium complexes were tested for the alkylation of aromatic amines with a wide range of primary alcohols under solvent-free conditions using the hydrogen borrowing strategy. All of the compounds tested here showed excellent catalytic activity for these reactions and N-monoalkylated products were obtained selectively using 2.5 mol% of the ruthenium complexes.
- Yi?it, Beyhan,?zge Karaca, Emine,Yi?it, Murat,Gürbüz, Nevin,Arslan, Hakan,?zdemir, ?smail
-
-
- First used of Alkylbenzimidazole-Cobalt(II) complexes as a catalyst for the N-Alkylation of amines with alcohols under solvent-free medium
-
In this study, alkylbenzimidazole-cobalt(II)-catalyzed direct N-alkylation reactions of amines with alcohols derivatives have been investigated under solvent-free medium. For this purpose, a series of cobalt(II) complexes bearing N-alkylbenzimidazole complexes have been synthesized and novel complexes fully characterized by elemental analysis, FT-IR, 1H NMR and, 13C{1H} NMR spectroscopies. Also, the structure of the complex 2a has been confirmed by X-ray crystallography. Generally, the N-alkylating reaction is usually performed in toluene with various metal complexes including cobalt. In this catalytic study of complexes, 2a-c has carried out in without solvent and alcohol acted both as solvent and reactant. Conversion and selectivity of amine products according to imine products for alkylation reactions have been seen high yield in medium solvent-free relative to in toluene.
- ?zdemir, ?smail,?zdemir, Nam?k,?ahin, Neslihan,Gürbüz, Nevin,Y?ld?r?m, ?lkay
-
-
- Borrowing hydrogen activity of NH2-MIL-125 for N-alkylation of amines with alcohols under solvent and base free condition
-
The NH2-MIL-125 showed excellent activity in solvent and base free N-alkylation of amines with alcohols via borrowing hydrogen mechanism. The Ti–O clusters of NH2-MIL-125 provide acidic-basic active sites for the catalysis of reaction. The NH2-MIL-125 was found to be stable and reusable in the reaction.
- Mishra, Manish Kumar,Neogi, Subhadip,Patel, Nisha B.,Shukla, Atindra,Vala, Naresh
-
-
- Direct reductive coupling of nitroarenes and alcohols catalysed by Co-N-C/CNT@AC
-
A non-noble heterogeneous catalyst-a Co, N and C composite encapsulated carbon nanotube grown in situ on the surface of activated carbon (Co-N-C/CNT@AC)-was fabricated via the pyrolysis-reduction process. Co-N-C/CNT@AC catalyzed the reductive coupling of structurally diverse nitroarenes and alcohols to imines and secondary amines under exogenous base- and solvent-free conditions. BET, TEM, SEM, XRD and XPS characterization showed that the exceptional catalytic property of Co-N-C/CNT@AC could be explained by its nanostructure, Co-N and basic N species. Our protocol had advantages of low cost, environment-friendliness, and good applicability. Furthermore, a reaction route of nitroarenes, amines and alcohols as the starting materials was proposed to improve the atom economy of the reductive coupling of nitroarenes with alcohols.
- Liu, Di,Yang, Ping,Zhang, Hao,Liu, Minjie,Zhang, Wenfei,Xu, Dongmei,Gao, Jun
-
p. 2129 - 2137
(2019/04/27)
-
- One-pot solvothermal synthesized CoS2@MoS2 nanocomposites for selective reduction coupling reaction to synthesize imines
-
Selective reduction coupling of nitroaromatics and aldehydes for imines synthesis has been investigated by using a series of bifunctional CoS2@MoS2 catalysts prepared by one-pot solvothermal method. Under optimal Co/Mo ratio of 0.75 and preparation temperature (180 °C), CoS2@MoS2–180-0.75 catalyst shows 96.5% nitrobenzene conversion, 93.0% imine selectivity and good versatility for substituted nitrobenzene and different aldehydes under mild conditions (60 °C, 1.5 MPa H2). The characterizations reveal that high nitroaromatics hydrogenation activity and good selectivity are mainly due to the formation of CoMoS phase, the coupling reaction between aniline derivatives and aldehydes is achieved by the appropriate acidity of CoS2@MoS2 nanocomposites.
- Han, Wenpeng,Wang, Junwei,Li, Xuekuan,Zhou, Ligong,Yang, Ying,Tang, Mingxing,Ge, Hui
-
-
- Synthesis of organoaluminum chalcogenides and their applications in Lewis acid catalysis
-
Two chalcogenide bridged bi-aluminum compounds [LAl(NMe3)(μ-S)Al(NMe3)L] (1) and [LAl(NMe3)(μ-Se)Al(NMe3)L] (2) were synthesized by reacting LAlH(NMe3) (L = 4-methylbenzylidene-o-aminothiophenol) with
- Ding, Yi,Ma, Xiaoli,Liu, Yashuai,Liu, Wenqing,Ni, Congjian,Yan, Ben,Yan, Li,Yang, Zhi
-
-
- 1,4-Dihydropyridine/BF3OEt2 for the reduction of imines: Influences of the amount of added BF3OEt2 and the substitution at N-1 and C-4 of the dihydropyridine ring
-
We have evaluated four 1,4-dihydropyridines (DHPs 1a, 1b, 1c and 1d) as reducing agents, which presented free (hydrogenated) or phenyl-substituted N-1 and C-4 positions of the DHP ring. Reactions combining each of the DHP and different amounts of BF3OEt2 were evaluated for the reduction of imine 2a (N-benzylideneaniline). DHP simultaneously substituted at N-1 and C-4 (1a), and DHP substituted at C-4 (1b) gave lower yields for reduction of 2a in comparison with DHPs 1c and 1d (both unsubstituted at the C-4 position). By evaluating the amount of added BF3OEt2 to the reaction mixture, we have found that DHP 1c (substituted at N-1) provided its best yield for amine 3a (82%) when associated with stoichiometric amounts BF3OEt2, while DHP 1d (N-1- and C-4-unsubstituted derivative) was more effective (90% yield) with catalytic quantities of the Lewis acid. The reaction system using DHP 1c under stoichiometric BF3OEt2 could also be successfully applied with additional imine examples and under reductive amination conditions.
- Zattoni, Ingrid F.,Guanaes, Lais D.,Cerqueira, Letícia B.,Pontarolo, Roberto,Ducatti, Diogo R.B.,Duarte, M. Eugênia R.,Noseda, Miguel D.,Trindade, Angela C.L.B.,Gon?alves, Alan G.
-
supporting information
(2019/09/12)
-
- Photoredox Radical/Polar Crossover Enables Construction of Saturated Nitrogen Heterocycles
-
Photoredox-mediated radical/polar crossover (RPC) processes offer new avenues for the synthesis of cyclic molecules. This process has been realized for the construction of medium-sized saturated nitrogen heterocycles. Photocatalytically generated alkyl ra
- Pantaine, Lo?c R.E.,Milligan, John A.,Matsui, Jennifer K.,Kelly, Christopher B.,Molander, Gary A.
-
supporting information
p. 2317 - 2321
(2019/03/26)
-
- α-Acyl-α-diazoacetates in Transition-Metal-Free β-Lactam Synthesis
-
Thermally promoted reaction of α-acyl-α-diazoacetates with imines has been investigated. The transformation, earlier reported predominantly under transition metal catalyzed conditions, delivers α-alkoxycarbonyl-substituted β-lactams with outstanding diastereoselectivity. DFT calculations performed in order to evaluate energetically feasible reaction pathways revealed the intermediacy of 1,3-oxazin-4-one intermediates hitherto never implicated in the Staudinger synthesis of β-lactams.
- Synofzik, Judith,Dar'In, Dmitry,Novikov, Mikhail S.,Kantin, Grigory,Bakulina, Olga,Krasavin, Mikhail
-
p. 12101 - 12110
(2019/10/02)
-
- Acceptorless dehydrogenative construction of CN and CC bonds through catalytic aza-Wittig and Wittig reactions in the presence of an air-stable ruthenium pincer complex
-
The construction of CN bonds was achieved by the dehydrogenative coupling of alcohol and azide via aza-Wittig type reaction. The reaction is catalyzed by an acridine-derived ruthenium pincer complex and does not use any oxidant. The present protocol offers a wide substrate scope, including aliphatic, aryl or heteroaryl alcohol/azides. This expeditious protocol was successfully applied to construct a CC bond directly from alcohol via dehydrogenative Wittig reaction. Furthermore, the synthesis of structurally important pyrrolo[1,4]benzodiazepine derivatives was also achieved by this methodology.
- Biswas, Nandita,Das, Kalicharan,Sardar, Bitan,Srimani, DIpankar
-
p. 6501 - 6512
(2019/05/24)
-
- A new kind of bismuth organic complex and its preparation method and catalytic applications (by machine translation)
-
This invention is a novel bismuth organic complex and its preparation method and catalytic applications. Characterized in that in order to commonly used organic solvent as a reaction solvent, in order to organic bismuth ion nitrogen atom ligand diphenyl [...] and cheap and easy to obtain aryl boric acid as the raw material, the nickel acetate catalytic reaction, high yield, high selectivity to obtain a novel bismuth organic (III) complex catalyst (I). The good stability of the catalyst, can be recovered, and in the catalytic aryl alkynes and aniline derivatives hydroamination reaction demonstrate excellent catalytic activity. This method has the advantages of low cost, high yield, simple and convenient operation, no pollution and the like, for the realization of its industrial production has certain feasibility. (by machine translation)
- -
-
Paragraph 0034; 0036; 0037; 0041
(2019/01/24)
-
- An Efficient Mesoporous Cu-Organic Nanorod for Friedl?nder Synthesis of Quinoline and Click Reactions
-
Within the green chemistry context, heterogeneous catalysis for the synthesis of N-heterocycles from renewable resources using non-precious metals has garnered great interest in terms of economic and environmental perspectives. Herein, we present a triazine functional hierarchical mesoporous organic polymer (HMOP) with nanorod morphology together with large BET surface area ~1218 m2 g?1, huge pore volumeγτ“;6 mL g?1 and dual micro/mesopore architectures. Subsequent Cu-coordination with nitrogen atoms of the HMOP provides a robust catalyst (Cu-HMOP) to accomplish multi-step cascade reactions for preparation of N-heterocycles by different routes. For instance, the Cu-HMOP efficiently catalyzes one-pot sequential multi-step oxidative dehydrogenative coupling of 2-aminobenzyl alcohol with diverse aromatic ketones to afford corresponding quinolines in excellent isolated yields (up to 97 %). Secondly, the present catalyst exhibits good aerobic oxidative dehydrogenation activity of amines to imines. Thirdly, for “click” reaction involving azides-alkynes, the Cu-HMOP produced quantitative yield for 1,4-disubstituted 1,2,3-triazole derivatives at room temperature using water as solvent. Verification of active metal leaching by a hot filtration test as well as reusability of the retrieved Cu-HMOP catalysts shows a consistent activity in the multi-component quinoline synthesis as model reaction.
- Elavarasan, Samaraj,Bhaumik, Asim,Sasidharan, Manickam
-
p. 4340 - 4350
(2019/08/12)
-
- Cobalt-Catalyzed Dehydrogenative Coupling of Amines into Imines
-
Primary amines have been subjected to an acceptorless dehydrogenative homo- and heterocoupling into imines with a cobalt catalyst. The catalytically active species are composed of cobalt nanoparticles, which are generated in situ by heating Co2(CO)8 in the presence of trioctylphosphine oxide as a surfactant. The nanoparticles have been characterized by transmission electron microscopy where the image showed spherical and small particles with a narrow size distribution. The catalyst can be recovered and used again with essentially no effect on the yield. The catalyst can also be used for the dehydrogenative coupling of alcohols and amines into imines.
- Bottaro, Fabrizio,Takallou, Ahmad,Chehaiber, Ahmad,Madsen, Robert
-
supporting information
p. 7164 - 7168
(2019/11/16)
-
- Oxygen-vacancies-engaged efficient carrier utilization for the photocatalytic coupling reaction
-
Defects can greatly optimize the solar light harvesting capability and electronic structure of oxide materials. However, it remains challenging to achieve a defect engineering strategy under mild conditions. Meanwhile, the simultaneous exploitation of photogenerated holes (h+) and electrons (e?) to promote both photooxidation and photoreduction in a coupled system has rarely been reported. For the first time, we reveal an oxygen-vacancies-mediated photocatalytic strategy in which the electrons and holes are fully utilized for nitrobenzene reduction coupled with benzyl alcohol oxidation. The oxygen vacancies (OVs) generated in situ on the surface of TiO2 greatly extend light absorption into the visible region and promote the photogenerated electron transport for efficient photocatalysis. The experimental and theoretical results together indicate that chemisorption on the TiO2 surface decreases the oxidation potential of benzyl alcohol and causes an upward shift in its HOMO, which facilitates the oxidation reaction of benzyl alcohol to benzaldehyde. The in situ generated surface OVs also act as a bridge to enable the trapping and transferring of the photoinduced electrons to the nitrobenzene. This work provides a new perspective of utilizing the chemisorption between the reactant and catalyst to achieve a defect engineering strategy for synergetic photocatalysis.
- Yang, Xue,Tao, Huilin,Leow, Wan Ru,Li, Jingjun,Tan, Yanxi,Zhang, Yongfan,Zhang, Teng,Chen, Xiaodong,Gao, Shuiying,Cao, Rong
-
p. 116 - 125
(2019/04/08)
-
- Ruthenium(II)-NHC-catalyzed (NHC = perhydrobenzimidazol-2-ylidene) alkylation of amines using the hydrogen borrowing methodology under solvent-free conditions
-
New ruthenium(II) complexes with N-heterocyclic carbene ligand were synthesized by transmetalation reactions between silver(I) N-heterocyclic carbene complexes and [RuCl2(p-cymene)]2. The complexes were characterized by physicochemical and spectroscopic methods. These ruthenium complexes were applied to the N-monoalkylation of aromatic amines with a wide range of primary alcohols under solvent-free conditions using the hydrogen borrowing strategy. The catalytic reactions using all ruthenium complexes resulted in N-monoalkylated products with high selectivities using furfuryl alcohol as the alkylating agent.
- Yi?it, Murat,Karaca, Emine ?zge,Yi?it, Beyhan,Gürbüz, Nevin,?zdemir, ?smail
-
p. 565 - 573
(2019/03/23)
-
- Switching the N-Alkylation of Arylamines with Benzyl Alcohols to Imine Formation Enables the One-Pot Synthesis of Enantioenriched α-N-Alkylaminophosphonates
-
The selective N-alkylation of anilines with benzylic alcohols can be switched in favor of the dehydrogenative condensation process using the nitrile-ligated Kn?lker's complex by conducting the reaction either in a closed system under inert conditions, or in an open system in air. The selective formation of imines, containing reactive C=N bonds, provides an opportunity towards further functionalization. Indeed, a one-pot three-component condensation of alcohols, amines and phosphites, promoted by an iron-based Kn?lker-type complex in combination with a chiral BINOL-based phosphoric acid, provides access to enantioenriched α-N-alkylaminophosphonates.
- Hofmann, Natalie,Hultzsch, Kai C.
-
supporting information
p. 3105 - 3111
(2019/06/08)
-
- The Divergent Cascade Reactions of Arylalkynols with Homopropargylic Amines or Electron-Deficient Olefins: Access to the Spiro-Isobenzofuran- b-pyrroloquinolines or Bridged-Isobenzofuran Polycycles
-
Two divergent cascade reactions of arylalkynols with homopropargylic amines or electron-deficient olefins were developed to synthesize the spiro-isobenzofuran-b-pyrroloquinolines or bridged-isobenzofuran heterocycles in good yields, respectively. One reaction actually involved intramolecular 5-endo-dig hydroamination cyclization-protonation of homopropargylic amines to give cycloiminium ions and intramolecular 5-exo-dig hydroalkoxylation cyclization of arylalkynols to generate isobenzofuran with exocyclic double bond, followed by the nontypical Povarov-type reaction in the presence of PtCl2/FeCl3 cocatalysts. The other underwent intramolecular hydroalkoxylation cycloisomerization of alkynols with the subsequent normal [4 + 2] cycoaddition with dienophiles. Herein, the arylalkynols acted as both "masked" electron-rich olefins and "masked" electron-rich dienes.
- Wang, Lun,Liu, Lingyan,Chang, Weixing,Li, Jing
-
supporting information
p. 7799 - 7813
(2018/06/18)
-
- Formic acid catalyzed one-pot synthesis of α-aminophosphonates: an efficient, inexpensive and environmental friendly organocatalyst
-
Abstract: Aqueous formic acid is used for the synthesis of α-aminophosphonates through Kabachnik–Fields reaction applying aromatic amine, phosphite, and carbonyl compounds. Using formic acid as an efficient and low-cost organocatalyst provides environmental friendly, high yields, low reaction time and mild reaction condition. The isolated products were analyzed by IR, NMR, and mass techniques. Graphical abstract: [Figure not available: see fulltext.].
- Azarnia Mehraban, Jamshid,Jalali, Mahsa Sadat,Heydari, Akbar
-
p. 2215 - 2223
(2018/08/04)
-
- One-pot cascade synthesis of pyrano/furanotetrahydroquinolines through povarov reaction catalyzed by Fe(NO3)3@Al2O3
-
Fe(NO3)3@Al2O3 was synthesized as a green heterogeneous catalyst for Povarov reaction toward the one-pot cascade synthesis of cis- and trans-tetrahydroquinolines from aryl amines, aryl aldehydes, and electron-rich olefins (dihydropyran/dihydrofuran) under thermal conditions. The reaction is diastereoselective with trans product formed in preponderance. The products were characterized by 1H NMR, 13C NMR, IR, ESIMS, and elemental analysis. The characterization of Fe(NO3)3@Al2O3 was made by various techniques such as Fourier-transform infrared, inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, energy dispersive X-ray, scanning electron microscope, transmission electron micrographs, TGA, and vibrating sample magnetometer. High catalytic activity, easy recovery and reusability, eco-benign nature, and thermal and chemical stabilities are the key properties of the catalyst that makes it attractive from the viewpoint of green chemistry.
- Kaur, Ramneet,Khajuria, Rajni,Saini, Yeshwinder,Kapoor, Kamal K.
-
-
- Cross-dehydrogenative coupling strategy for phosphonation and cyanation of secondary N-alkyl anilines by employing 2,3-dichloro-5,6-dicyanobenzoquinone
-
The cross-dehydrogenative coupling strategy for metal-free phosphonation and cyanation of secondary N-alkyl anilines has been developed firstly under mild reaction conditions. Based on detailed optimization of reaction conditions, the substrate generality of N-alkyl anilines and various hydrogen phosphonates has been investigated, and a series of versatile α-aminophosphonates and α-aminonitriles were therefore furnished in good to excellent yields. A plausible collective reaction mechanism through dehydrogenation to imine formation, then to respective α-aminophosphonates and α-aminonitriles was proposed.
- Liu, Qing,Yu, Shuchen,Hu, Liangzhen,Hussain, Muhamad Ijaz,Zhang, Xiaohui,Xiong, Yan
-
p. 7209 - 7217
(2018/11/10)
-
- Design and stereoselective synthesis of novel β-lactone and β-lactams as potent anticancer agents on breast cancer cells
-
To produce a novel class of anticancer compounds, an efficient method for synthesizing novel β-lactone and β-lactam frameworks was developed based on the reaction of a new ketene with C=O and C=N bonds. Functionalized 2-azetidinones were efficiently synthesized by employing 2,4-dichlorophenoxylketene, which was generated in situ. The reaction of the ketene with aldehydes was not successful and in all cases except for 4-nitrobenzaldehyde, a rearranged dimer of the ketene was obtained as a lactone. Anticancer cellular activity of all new β-lactams and lactones on breast cancer cells was studied. All new synthesized compounds exhibited potential anticancer activity which may guarantee their future application in moderate chemotherapy.
- Rashidi, Mahnoosh,Islami, Mohammad Reza,Esmaeili-Mahani, Saeed
-
p. 835 - 841
(2018/01/22)
-