Chan Lam Coupling Reaction Research Articles

Developing oxygen vacancy-rich CuMn2O4/carbon dots dual-function nanozymes via Chan-Lam coupling reaction for the colorimetric/fluorescent determination of D-penicillamine

Defect engineering is a promising approach to construct high performance nanozymes due to its ability to regulate their physical and chemical properties. However, how to construct defects to improve the activity of nanozymes remains a challenge. Herein, for the first time, the Chan-Lam coupling reaction is used to construct the oxygen vacancy (OV)-rich CuMn2O4/carbon dots (CDs) (OV-CuMn2O4/CDs) dual-function nanozymes with fluorescent (FL) and oxidase-like properties, via regulating the low-valent metal ions (Cu+ and Mn2+) and Ov contents in the spinel CuMn2O4 and in-situ growth of β-cyclodextrin (β-CD)-derived CDs. Expectedly, relative to CuMn2O4, the OV-CuMn2O4/CDs exhibited 35.8%, 8.5%, and 14.6% rise in the contents of Cu+, Mn2+ and Ov, respectively. Abundant Ov provides more O2 adsorption/activation sites, and the charge transfer between Ov and metal atoms increases the charge density around metal atoms. This produces more low-valent metals (like Cu+ and Mn2+) to promote the electron transfer from metal to O atoms and O-O bond cleavage. Thus, the oxidase-like activity of OV-CuMn2O4/CDs is 4.1 times that of CuMn2O4. Also, the in-situ growth of β-CD-derived carbon dots on CuMn2O4 endows OV-CuMn2O4/CDs selective target recognition. Thus, a sensitive and selective colorimetric and fluorescence dual-mode method was established for determining D-penicillamine (D-PA), with the limit of detection of 0.25 and 0.048 μM, respectively. The method was applied to D-PA determination in real samples. This work demonstrates the Chan-Lam coupling reaction can be used to construct high performance nanozymes for developing dual-mode sensor for the detection of targets.

Zn, Cd and Cu Coordination Polymers for Metronidazole Sensing and for Ullmann and Chan-Lam Coupling Reactions.

Five compounds, [Zn2(bpe)(BPTA)2(H2O)2] ⋅ 2H2O (1); [Zn(bpe)(BPTA)] (2); [Cd(bpe)(BPTA)H2O] (3); [Cd(BPTA) (bpmh)] ⋅ 2H2O (4); and Cu2(BPTA)2(bpmh)3(H2O)2] ⋅ 2H2O (5) were prepared employing 2,5-bis(prop-2-yn-1-yloxy)terephthalic acid (2, 5 BPTA) as the primary ligand and 1,2-di(pyridin-4-yl)ethane (4, 4' bpe) (1-3) and 1,2-bis(pyridin-3-ylmethylene)hydrazine (bpmh) (4-5) as the secondary ligands. Single crystal studies indicated that the compounds 1, 3 and 5 have two-dimensional layer structures and compounds 2 and 4 three-dimensional structures. The luminescence behaviour of the compounds 2 and 3 were explored for the sensing of metronidazole in aqueous medium. The studies indicated that the compounds can detect metronidazole in ppm level both in solution as well as simple paper strips. The Cu compound 5 was found to lose the coordinated water molecule at 100 °C without any structural change. The coordinatively unsaturated Cu-centre were examined towards the Lewis acidic character by carrying out the Ullmann type C-C homocoupling reaction of the aromatic halide compounds. The compounds, 4 and 5, also have the Lewis basic functionality arising out the =N-N=, aza groups. The bifunctional nature of the coordination polymers (CP) was explored towards the Chan-Lam coupling reaction between phenyl boronic acid and aniline derivatives in the ethanol medium. In both the catalytic reactions, good yields and recyclability were observed. The present studies illustrated the rich diversity that the transition metal containing compounds exhibit in extended framework structures.

Magnetic Mesoporous Silica Nanocomposite Supported Ionic Liquid/Cu as a Powerful and Highly Stable Catalyst for Chan-Lam Coupling Reaction

Magnetic Mesoporous Silica Nanocomposite Supported Ionic Liquid/Cu as a Powerful and Highly Stable Catalyst for Chan-Lam Coupling Reaction

Magnetically recoverable CuFe2O4 nanocatalyst: Dual catalytic action in sonogashira and Chan-Lam coupling reactions

Magnetically retrievable CuFe2O4 nanocatalyst has been synthesized for Sonogashira (C-C) and Chan-Lam (C-N) coupling reactions by a facile co-precipitation method. Synthesized nanocatalyst was characterized by powder x-ray diffraction (PXRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM) analysis. The catalytic action of the catalyst was evaluated for both Pd-free C-C coupling and base-free C-N coupling reactions where an excellent product yield up to 96 % and 95 % respectively was obtained. The uniqueness of the catalyst was its effective performance under ambient reaction conditions in green solvents such as EtOH and EtOH:H2O (1:1) with a broad substrate scope. The catalyst can be easily retrieved from the reaction mixture with the aid of an external magnet and reused at least five times without significant loss in catalytic activity. The structural stability of the recovered catalyst was confirmed by XRD, FTIR, SEM and ICP-OES (Inductively coupled plasma - optical emission spectrometry) analysis. Thus, the synthesized catalyst works excellently well for dual applications and establishes the sustainable application of the catalyst.

Syntheses and Structure-Activity Relationship Studies of Antitumor Bicyclic Hexapeptide RA-VII Analogues

A series of antitumor bicyclic hexapeptide RA-VII analogues modified at residue 2, 3, or 6 were prepared by the chemical transformation of the hydroxy, methoxy, or carboxy groups or the aromatic rings of natural peptides RA-II, III, V, VII, and X. Analogues with modified side chains or peptide backbones, which cannot be prepared by the chemical transformation of their natural peptides, and newly isolated peptides from Rubia cordifolia roots were synthesized by using protected cycloisodityrosines prepared by the degradation of bis(thioamide) obtained from RA-VII or the diphenyl ether formation of boronodipeptide under the modified Chan-Lam coupling reaction conditions. Studies of the conformational features of the analogues and the newly isolated peptides and their relationships with cytotoxic activities against the HCT-116, HL-60, KATO-III, KB, L1210, MCF-7, and P-388 cell lines revealed the following: the methoxy group at residue 3 is essential for the potent cytotoxic activity; the methyl group at Ala-2 and Ala-4 but not at D-Ala-1 is required to establish the bioactive conformation; the N-methyl group at Tyr-5 is necessary for the peptides to adopt the active conformation preferentially; and the orientation of Tyr-5 and/or Tyr-6 phenyl rings has a significant effect on the cytotoxic activity.

Recent advances in Chan–Lam coupling reaction

Chan–Lam coupling has evolved as a shining star among C–heteroatom coupling reactions because of its greener open flask chemistry and tremendous possibilities in terms of substrate bank, catalyst varieties, unlocking nature friendly conditions, etc.

Copper Complexes with N,N,N-Tridentate Quinolinyl Anilido-Imine Ligands: Synthesis and Their Catalytic Application in Chan-Lam Reactions.

The treatment of 2-(ArNC(H))C6H4-HNC9H6N with n-BuLi and the subsequent addition of CuCl2 afforded the anilido-aldimine Cu(II) complexes 1-5 Cu[{2-[ArN=C(H)]C6H4}N(8-C9H6N)]Cl (Ar = 2,6-iPr2C6H3 (1), 2,4,6-(CH3)3C6H2 (2), 4-OCH3C6H4 (3), 4-BrC6H4 (4), 4-ClC6H4 (5)), respectively. All the copper complexes were fully characterized by IR, EPR and HR-MS spectra. The X-ray diffraction analysis reveals that 2 and 4 are mononuclear complexes, and the Cu atom is sitting in a slightly square-planar geometry. These Cu(II) complexes have exhibited excellent catalytic activity in the Chan-Lam coupling reactions of benzimidazole derivatives with arylboronic acids, achieving the highest yields of up to 96%.

Visible-Light-Responsive Nano CuO/ZnO Photocatalyst for Chan–Lam Coupling Reaction and Aerobic C(sp3)–H Bond Oxidation

AbstractWhen it comes to heterogeneous photocatalysts, semiconductors are the best candidate with a high potential to respond in visible-light regions. In this study, semiconductor p-n heterojunction, nano CuO/ZnO, was synthesized via a simple, sustainable, and low-cost approach. Photocatalytic activity of the synthesized material with a 2.02 eV band gap was investigated in the Chan–Lam coupling reaction and C(sp3)–H bond oxidation of alkyl aromatic compounds under visible-light irradiation in aqueous solution. In the case of the Chan–Lam coupling reaction, various derivatives of aniline and arylboronic acid successfully took part in the reaction, delivering the desired products in 57–89% yields. In addition, nano CuO/ZnO photocatalyst showed high efficiency in the C(sp3)–H bond oxidation of alkyl aromatic compounds under air as a green oxidant. Noticeably, the photocatalyst showed high performance in the large-scale synthesis of desired products and maintained activity after several uses.

Metal–organic frameworks with open metal sites act as efficient heterogeneous catalysts for Knoevenagel condensation and the Chan–Lam coupling reaction

Two robust metal–organic Frameworks (MOFs) with distinct and diverse network topologies containing open metal sites are successfully employed as heterogeneous catalysts for the Knoevenagel condensation and the Chan–Lam cross coupling reaction.

Synthesis of a chiral dinuclear Cu(II)-benzothiazolamine complex: evidence of cuprophilic interaction in its structure and exploration of its electrochemical properties and catalytic performance.

The synthesis of a chiral dinuclear [Cu(OAc)2(L1)]2 complex (A) and its analogues Cu(OAc)2(L1)2 (B), Cu(OAc)2(L1)PPh3 (C), CuBr(L1)PPh3 (D), and Cu(OAc)2(L2) (E) is described. The X-ray structure of A reveals a cuprophilic interaction (2.65 Å) and shows that L1 behaves as a monodentate ligand. The stereogenic centre in L1 aligns the NH group to form non-covalent interactions with the paddle-wheel acetate groups at variable distances (2.4-2.5 Å and 2.2-2.7 Å). Thermogravimetric analysis confirmed our hypothesis that two equivalents of L1 (B) or a combination of L1 and PPh3 (C) would disrupt the cuprophilic interaction. All complexes, except D, showed irreversible redox waves by cyclic voltammetry. Complexes C and E have lower oxidative peaks (at 10 V s-1) than complex A between +0.40 and +0.60 V. This highlights the influence of ligand(s) on the redox behaviour of Cu(II) complexes. The significance of this electrochemical behaviour was evident in the Chan-Lam (CL) coupling reaction, where 2.5 mol% of A successfully facilitated the formation of a C-N bond. This study showcased the structure, thermal stability, electrochemical properties and catalytic performance of a chiral dinuclear copper(II)-benzothiazolamine complex.

Cu(BF4)2/AC-Catalyzed Synthesis of N-Substituted Anilines, N-Substituted 1,6-Naphthyridin-5(6H)-one, and Isoquinolin-1(2H)-one.

Herein, we report practical Cu(BF4)2/activated carbon-catalyzed amination of various anilines, isoquinolinone, and naphthyridinone with aryl boronic acids. The ultrasonic and rotary evaporation treatment of the mixture of aq. Cu(BF4)2 and activated carbon in methanol afforded a novel Cu(II)-catalyst, which is air-stable and can be effectively applied in the Chan-Lam coupling reaction. The products of N-arylation were isolated in good to excellent yields at low catalytic loading. And Cu(BF4)2/AC also showed good reusability.

Copper Catalyst-Supported Modified Magnetic Chitosan for the Synthesis of Novel 2-Arylthio-2,3-dihydroquinazolin-4(1H)-one Derivatives via Chan–Lam Coupling

In this paper, magnetic chitosan is used as a support for the immobilization of copper catalyst (Cu@MChit). The fabricated catalyst is successfully synthesized and characterized by several techniques. The activity of Cu@MChit catalyst is evaluated in the synthesis of novel derivatives of 3-alkyl-2-arylthio-2,3-dihydroquinazolin-4(1H)-ones. The products are synthesized in three simple steps via Chan–Lam coupling reaction. The synthetic route is based on the reaction of isatoic anhydride and an amine, followed by the reaction with carbon disulfide. Cu@MChit-catalyzed reaction of the obtained intermediate with phenylboronic acid leads to the desired products. The scope of the reaction is confirmed by using various amine and phenylboronic acid derivatives and the products are obtained in high isolated yields.

Biomolecule-Compatible Dehydrogenative Chan-Lam Coupling of Free Sulfilimines.

Inspired by the discovery of a S═N bond in the collagen IV network and its essential role in stabilizing basement membranes, sulfilimines have drawn much attention in the fields of chemistry and biology. However, their further uptake is hindered by the lack of mild, efficient, and environmentally benign protocols by which sulfilimines can be constructed under biomolecule-compatible conditions. Here, we report a terminal oxidant-free copper-catalyzed dehydrogenative Chan-Lam coupling of free diaryl sulfilimines with arylboronic acids with excellent chemoselectivity and broad substrate compatibility. The mild reaction conditions and biomolecule-compatible nature allow the employment of this protocol in the late-stage functionalization of complex peptides, and more importantly, as an effective bioconjugation method as showcased in a model protein. A combined experimental and computational mechanistic investigation reveals that an inner-sphere electron-transfer process circumvents the sacrificial oxidant employed in traditional Chan-Lam coupling reactions. An energetically viable concerted pathway was located wherein a copper hydride facilitates hydrogen-atom abstraction from the isopropanol solvent to produce dihydrogen via a four-membered transition state.

Reproducing the invention of a named reaction: zero-shot prediction of unseen chemical reactions.

While state-of-art models can predict reactions through the transfer learning of thousands of samples with the same reaction types as those of the reactions to predict, how to prepare such models to predict "unseen" reactions remains an unanswered question. We aimed to study the Transformer model's ability to predict "unseen" reactions through "zero-shot reaction prediction (ZSRP)", a concept derived from zero-shot learning and zero-shot translation. We reproduced the human invention of the Chan-Lam coupling reaction where the inventor was inspired by the Suzuki reaction when improving Barton's bismuth arylation reaction. After being fine-tuned with samples from these two "existing" reactions, the USPTO-trained Transformer could predict "unseen" Chan-Lam coupling reactions with 55.7% top-1 accuracy. Our model could also mimic the later stage of the history of this reaction, where the initial case of this reaction was generalized to more reactants and reagents via "one-shot/few-shot reaction prediction (OSRP/FSRP)" approaches.

Recent Progress on Chan-Lam Coupling Reactions Catalyzed by Copper(II) Complexes

Recent Progress on Chan-Lam Coupling Reactions Catalyzed by Copper(II) Complexes

Research Progress of Chan-Lam Coupling Reaction in Heterogeneous Catalysis

Research Progress of Chan-Lam Coupling Reaction in Heterogeneous Catalysis

Unified Approach to Benzo[d]thiazol-2-yl-Sulfonamides.

In this paper, we report a unified approach to N-substituted and N,N-disubstituted benzothiazole (BT) sulfonamides. Our approach to BT-sulfonamides starts from simple commercially available building blocks (benzo[d]thiazole-2-thiol and primary and secondary amines) that are connected via (a) a S oxidation/S-N coupling approach, (b) a S-N coupling/S-oxidation sequence, or via (c) a S-oxidation/S-F bond formation/SuFEx approach. The labile N-H bond in N-monoalkylated BT-sulfonamides (pKa (BTSO2N(H)Bn) = 3.34 ± 0.05) further allowed us to develop a simple weak base-promoted N-alkylation method and a stereoselective microwave-promoted Fukuyama-Mitsunobu reaction. N-Alkyl-N-aryl BT-sulfonamides were accessed with the help of the Chan-Lam coupling reaction. Developed methods were further used in stereo and chemoselective transformations of podophyllotoxin and several amino alcohols.

Biomass-Derived Activated Carbon-Supported Copper Catalyst: An Efficient Heterogeneous Magnetic Catalyst for Base-Free Chan-Lam Coupling and Oxidations.

Development of heterogeneous catalysts from biomass-derived activated carbon is a challenging task. Biomass-derived activated carbon possesses a large specific surface area, highly porous structure, and good thermal/chemical stability. Magnetic copper catalysts based on biomass-derived activated carbon exhibited good catalytic activity in base-free Chan–Lam coupling and oxidations. Herein, biomass-derived activated carbon was prepared by the carbonization of neem dead leaves (abundant waste biomass) followed by chemical activation with KOH. Such a porous carbon material was used as a low cost and highly efficient support material for the preparation of inexpensive and environmentally benign magnetic catalysts [Cu@KF-C/MFe2O4, M = Co, Cu, Ni, and Zn]. In addition, KF modification was done to impart basic character to the catalyst that can perform C–N coupling under base-free conditions. Initially, Brunauer–Emmett–Teller (BET) analysis of the synthesized catalysts was carried out, which indicated that Cu@KF-C/CoFe2O4 possess more surface area as well as pore volume, and so accounting for the highest activity among the other synthesized catalysts. Further, X-ray photoelectron spectroscopy (XPS) analysis was performed, which inferred that Cu@KF-C/CoFe2O4 contains most of the copper in reduced form, i.e., Cu(0), which is the active species responsible for better catalytic activity toward Chan–Lam coupling reactions as well as oxidation of alcohols and hydrocarbons. The physiochemical properties of the most active catalyst, Cu@KF-C/CoFe2O4, was examined by BET, XPS, Fourier transform infrared Spectroscopy (FTIR), thermogravimetric analysis (TGA), field emission gun scanning electron microscopy (FEG-SEM), high-resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray (EDX) mapping, energy dispersive X-ray (EDX), inductively coupled plasma atomic emission spectroscopy (ICP-AES), powder X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Moreover, Cu@KF-C/CoFe2O4 shows excellent stability as well as reusability and could be easily separated with the help of an external magnet.

Chitosan nanoparticles functionalized poly‐2‐hydroxyaniline supported CuO nanoparticles: An efficient heterogeneous and recyclable nanocatalyst for N‐arylation of amines with phenylboronic acid at ambient temperature

AbstractThe present study aims to prepare an effective and eco‐friendly nanocatalyst for the Chan–Lam coupling reaction of phenylboronic acid and amine in aerobic conditions. For this purpose, chitosan was extracted from shrimp shells waste by demineralization, deproteinization, and deacetylation processes and then converted to chitosan nanoparticles (CSN) by the ionic gelation with tripolyphosphate anions. Afterward, poly‐2‐hydroxyaniline (P2‐HA) was grafted to chitosan nanoparticles (NPs) to employ as the support for CuO NPs. Characterization of the nanocatalyst was done using Fourier transform infrared (FT‐IR), X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), mapping, energy‐dispersive X‐ray spectroscopy (EDS), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The CuO NPs were identified in the spherical shape with an average size of 17 nm. The prepared nanocatalyst exhibited excellent catalytic performance with a high turnover number (TON) and turnover frequency (TOF) for the Chan–Lam coupling reaction of phenyl boronic acid and amines with different electronic properties. The prepared catalyst could be readily recovered and reused for at least five runs without any noticeable change in structure and catalytic performance.Chitosan (CS) was prepared via demineralization, deproteinization, and deacetylation of shrimp shell and chitosan nanoparticles (CSN) were prepared via ionic gelation process. Polymerization of 2‐HA on the CSN surface was done to increase functional groups and create active sites for CuO NPs attachments. CuO NPs‐P2‐HA‐CSN nanocomposite has been shown high efficiently for the Chan–Lam coupling reaction.

A base-free Chan–Lam reaction catalyzed by an easily assembled Cu(II)-carboxylate metal-organic framework

A new copper(II) metal-organic framework is constructed as a sustainable copper heterogeneous catalyst. Cu-DPTCA, with high catalytic activity, can effectively promote the Chan–Lam coupling reaction of arylboronic acids and amines without adding any base or additive.