2050-85-3Relevant articles and documents
Chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes using carbon-supported palladium catalytic system in water
Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
, p. 3289 - 3312 (2021/05/11)
Developing and/or modifying fundamental chemical reactions using chemical industry-favorite heterogeneous recoverable catalytic systems in the water solvent is very important. In this paper, we developed convenient, green, and efficient approaches for the chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes in the presence of the recoverable heterogeneous carbon-supported palladium (Pd/C) catalytic system in water. The utilize of the simple, effective, and recoverable catalyst and also using of water as an entirely green solvent along with relatively short reaction times and good-to-excellent yields of the desired products are some of the noticeable features of the presented synthetic protocols. Graphic abstract: [Figure not available: see fulltext.].
The immobilized copper species on nickel ferrite (NiFe2O4@Cu): a magnetically reusable nanocatalyst for one-pot and quick reductive acetylation of nitroarenes to N-arylacetamides
Zeynizadeh, Behzad,Shokri, Zahra,Mohammadzadeh, Iman
, p. 859 - 870 (2019/12/24)
In this study, a green protocol for synthesis of N-arylacetamides was introduced. Magnetically, nanoparticles of the immobilized copper species on nickel ferrite, NiFe2O4@Cu, were synthesized and then characterized using SEM, EDX, XRD, VSM, ICP-OES, BET and XPS analyses. The XPS analysis approved that the immobilized copper species on NiFe2O4 only contain Cu(0) and its oxide form as CuO. The prepared nanocomposite system represented a perfect catalytic activity toward one-pot and quick reductive acetylation of various nitroarenes to the corresponding N-arylacetamides. All reactions were carried out in a mixture of H2O–EtOH (1.5–0.5) within 2–10?min using the combination system of NaBH4 and Ac2O in a one-pot approach and via a two-step procedure. The utilized Cu nanocomposite was magnetically separated from the reaction mixture and reused for 5 consecutive cycles without the significant loss of its catalytic activity.
1,2-Disubstituted Benzimidazoles by the Iron Catalyzed Cross-Dehydrogenative Coupling of Isomeric o-Phenylenediamine Substrates
Foss, Frank W.,Palacios, Philip M.,Pierce, Brad S.,Thapa, Pawan,Tran, Tam
, p. 1991 - 2009 (2020/03/13)
Benzimidazoles are common in nature, medicines, and materials. Numerous strategies for preparing 2-arylbenzimidazoles exist. In this work, 1,2-disubstituted benzimidazoles were prepared from various mono- and disubstituted ortho-phenylenediamines (OPD) by iron-catalyzed oxidative coupling. Specifically, O2 and FeCl3·6H2O catalyzed the cross-dehydrogenative coupling and aromatization of diarylmethyl and dialkyl benzimidazole precursors. N,N′-Disubstituted-OPD substrates were significantly more reactive than their N,N-disubstituted isomers, which appears to be relative to their propensity for complexation and charge transfer with Fe3+. The reaction also converted N-monosubstituted OPD substrates to 2-substituted benzimidazoles; however, electron-poor substrates produce 1,2-disubstituted benzimidazoles by intermolecular imino-transfer. Kinetic, reagent, and spectroscopic (UV-vis and EPR) studies suggest a mechanism involving metal-substrate complexation, charge transfer, and aerobic turnover, involving high-valent Fe(IV) intermediates. Overall, comparative strategies for the relatively sustainable and efficient synthesis of 1,2-disubstituted benzimidazoles are demonstrated.
Synthesis of diverse libraries of carboxamides via chemoselective N-acylation of amines by carboxylic acids employing Br?nsted acidic IL [BMIM(SO3H)][OTf]
Savanur, Hemantkumar M.,Malunavar, Shruti S.,Prabhala, Pavankumar,Sutar, Suraj M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
supporting information, (2019/09/30)
Chemoselective N-acylation of amines with carboxylic acids as acyl electrophiles and Br?nsted acidic IL [BMIM(SO3H)][OTf] as promoter is reported under both thermal and microwave irradiation to produce libraries of carboxamides in good to excellent yields after a simple workup. The protocol is compatible with structurally diverse 1° and 2° amines and works in the presence of sensitive functional groups such as thiols and phenols. The potential for recycling and reuse of the IL is also demonstrated.
Ni2B@Cu2O and Ni2B@CuCl2: two new simple and efficient nanocatalysts for?the green one-pot reductive acetylation of nitroarenes and direct N-acetylation of arylamines using solvent-free mechanochemical grinding
Zeynizadeh, Behzad,Younesi, Reza,Mousavi, Hossein
, p. 7331 - 7352 (2018/08/25)
Abstract: Ni2B@Cu2O and Ni2B@CuCl2 are introduced as simple and efficient earth-abundant transition-metal-based nanocomposites for the?green one-pot reductive acetylation of aromatic nitro compounds and direct N-acetylation of arylamines using a solvent-free mechanochemical grinding technique. The designed Ni2B-based nanocomposites were characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy. Notable advantages of these methods include broad substrate scope, use of a solvent-free mechanochemical grinding technique, implementation of earth-abundant transition-metal-based nanocomposites as simple and practical catalysts, and short reaction time and high yield at ambient condition. The mentioned methods can also be successfully applied for the?synthesis of a broad range of other amides (especially substituted acetamides) using green chemistry protocols. Also, the recoverability and reusability of the mentioned new nanocomposites were investigated. Graphical abstract: [Figure not available: see fulltext.].
Phosphinate selective hosts and importance of C–H hydrogen bonding for affinity modulation toward anion guests
Sohn, Dae Hyup,Han, Eunbi,Cho, Seung Joo,Kang, Jongmin
supporting information, p. 1728 - 1732 (2018/04/05)
Even though phosphinate and its analogs are very important guests in nature, the artificial receptors which are capable of selective recognition of phosphinate are rare. Here, we report a series of acetate and phosphinate selective hosts (1, 2 and 3) which utilize amide N–H and aliphatic C–H groups as hydrogen bonding donors. In this series of receptors, even though the amide N–H hydrogen bonding element was found to be the most significant, by varying the polarity of C–H group, the magnitude of recognition could be modulated considerably. The affinities of host 3 against all the tested anion guests showed significantly higher affinities compared with those of hosts 1 and 2, and this could be attributed to the difference of C–H group polarities among the receptors 1, 2 and 3. Cα-H hydrogen in host 3 is the most highly polarized by the charged pyridinium group. Therefore, it is the strongest host in this series of hosts. From the experiments shown here, we demonstrated the importance of C–H hydrogen bonding element as a decisive modulating moiety for anionic recognition.
Impregnated copper on Fe3O4: an efficient magnetically separable nanocatalyst for rapid and selective acylation of amines
Shokri, Zahra,Zeynizadeh, Behzad
, p. 2467 - 2474 (2017/10/30)
The present paper describes the synthesis of N-arylacetamides through acetylation of arylamines with Ac2O in the presence of magnetically recyclable Fe3O4/Cu NPs. All reactions were carried out efficiently in H2O within 2–10?min to give the products in 89–95% yields. Selective acetylation of amines versus alcohols was carried out successfully with this acetylating system. In addition, acetylation of amines and phenols was taken place with the same reactivity. Reusability of the nanocatalyst was examined 5 times without significant loss of its catalytic activity.
Pd(II)-Catalyzed Aerobic Intermolecular 1,2-Diamination of Conjugated Dienes: A Regio- and Chemoselective [4 + 2] Annulation for the Synthesis of Tetrahydroquinoxalines
Wu, Zhengxing,Wen, Ke,Zhang, Jingang,Zhang, Wanbin
supporting information, p. 2813 - 2816 (2017/06/07)
A Pd(II)-catalyzed aerobic intermolecular 1,2-diamination of conjugated dienes was developed for the regio- and chemoselective preparation of a variety of functionalized tetrahydroquinoxalines, using simple sulfonyl protected o-phenylendiamines as a nitrogen source. This methodology provides a direct and efficient synthesis of tetrahydroquinoxalines. O2 was used as the stoichiometric oxidant, and reaction conditions were applied to a series of o-phenylendiamines and conjugated dienes. 35 examples are described, and good yields and selectivities are obtained for the majority of the products.
Eco-friendly, catalyst and solvent-free, synthesis of acetanilides and N-benzothiazole-2-yl-acetamides
Cunha, Silvio,De Santana, Louren?o L. B.
, p. 1137 - 1144 (2017/05/01)
An expeditious and green synthesis of acetamides in a solvent-free simple way is described, without catalyst or additives, and in good yield by an instantaneous reaction of anilines or 2-aminothiazoles and acetic anhydride without external heating, and with simple purification. Sixteen substituted acetanilides and four N-benzothiazole-2-yl-acetamides were formed, but aliphatic amines of low molecular weight were not as effective as aromatic ones, and only cyclohexylamine and the enaminone ethyl 3-amino-2-butenoate afforded the corresponding acetamides in good yield.
Iterative C?H Functionalization Leading to Multiple Amidations of Anilides
Park, Juhyeon,Lee, Jia,Chang, Sukbok
, p. 4256 - 4260 (2017/04/04)
Polyaminobenzenes were synthesized by the ruthenium-catalyzed iterative C?H amidation of anilides using dioxazolones as an amino source. This strategy could be implemented by the sequential activation of C?H bonds of formerly generated compounds by cascade chelation assistance of newly installed amide groups. Computational studies provided a rationale.
