- Visible-Light Carbon Nitride-Catalyzed Aerobic Cyclization of Thiobenzanilides under Ambient Air Conditions
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A metal-free heterogeneous photocatalysis has been developed for the synthesis of benzothiazoles via intramolecular C-H functionalization/C-S bond formation of thiobenzanilides by inexpensive graphitic carbon nitride (g-C3N4) under visible-light irradiation. This reaction provides access to a broad range of 2-substituted benzothiazoles in high yields under an air atmosphere at room temperature without addition of a strong base or organic oxidizing reagents. In addition, the catalyst was found to be stable and reusable after five reaction cycles.
- Bai, Jin,Yan, Sijia,Zhang, Zhuxia,Guo, Zhen,Zhou, Cong-Ying
-
supporting information
p. 4843 - 4848
(2021/06/28)
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- Photocatalyzed Triplet Sensitization of Oximes Using Visible Light Provides a Route to Nonclassical Beckmann Rearrangement Products
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Oximes are valuable synthetic intermediates for the preparation of a variety of functional groups. To date, the stereoselective synthesis of oximes remains a major challenge, as most current synthetic methods either provide mixtures of E and Z isomers or furnish the thermodynamically preferred E isomer. Herein we report a mild and general method to achieve Z isomers of aryl oximes by photoisomerization of oximes via visible-light-mediated energy transfer (EnT) catalysis. Facile access to (Z)-oximes provides opportunities to achieve regio- and chemoselectivity complementary to those of widely used transformations employing oxime starting materials. We show an enhanced one-pot protocol for photocatalyzed oxime isomerization and subsequent Beckmann rearrangement that enables novel reactivity with alkyl groups migrating preferentially over aryl groups, reversing the regioselectivity of the traditional Beckmann reaction. Chemodivergent N- or O- cyclizations of alkenyl oximes are also demonstrated, leading to nitrones or cyclic oxime ethers, respectively.
- Zhang, Xiao,Rovis, Tomislav
-
supporting information
p. 21211 - 21217
(2021/12/27)
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- An Environmentally Benign, Catalyst-Free N?C Bond Cleavage/Formation of Primary, Secondary, and Tertiary Unactivated Amides
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Herein, we report an operationally simple, cheap, and catalyst-free method for the transamidation of a diverse range of unactivated amides furnishing the desired products in excellent yields. This protocol is environmentally friendly and operates under extremely mild conditions without using any promoter or additives. Significantly, this strategy has been implied in the chemoselective synthesis of a pharmaceutical molecule, paracetamol, on a gram-scale with excellent yield. We anticipate that this universally applicable strategy will be of great interest in drug discovery, biochemistry, and organic synthesis.
- Kumar, Vishal,Dhawan, Sanjeev,Girase, Pankaj Sanjay,Singh, Parvesh,Karpoormath, Rajshekhar
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p. 5627 - 5639
(2021/11/11)
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- Fe-mediated synthesis of: N -aryl amides from nitroarenes and acyl chlorides
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Amides are prevalent in nature and valuable functional compounds in agrochemical, pharmaceutical, and materials industries. In this work, we developed a selective and mild method for the synthesis of N-aryl amides. Starting from commercially available nitroarenes and acyl halides, N-aryl amides with good yields can be obtained in water. Especially in the process of transformation, Fe dust is the only reductant and additive, and the reaction can be easily performed on a large scale.
- Wu, Yundong,Guo, Lei,Liu, Yuxuan,Xiang, Jiannan,Jiang, Jun
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p. 15290 - 15295
(2021/05/19)
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- Visible-light induced one-pot hydrogenation and amidation of nitroaromatics with carboxylic acids over 2D MXene-derived Pt/N-TiO2/Ti3C2
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Pt nanoparticles supported on N doped titanium dioxide/titanium carbide (MXene) heterojunctions were employed as photocatalysts for the tandem reactions between aromatic nitro compounds and carboxylic acids to produce amide products. The 3%Pt/N-TiO2/Ti3C2 heterojunction was prepared by in situ grew TiO2 on Ti3C2 nanosheets and then N doped TiO2 with melamine, Pt nanoparticles with 3.3 nm mean diameter well dispersed on N-TiO2/Ti3C2. 3%Pt/N-TiO2/Ti3C2 had excellent amidation activity and chemoselectivity under visible-light irradiation. The elevated catalytic performance of 3%Pt/N-TiO2/Ti3C2 was owing to the improvement in photogenerated electron and hole separation efficiency through charge short-range directional transmission caused by the intimate contact between the TiO2 and the conductive Ti3C2. This direct hydrogenation along with amidation between nitroaromatics and carboxylic acids own actual merits in the amides produce with no harmful byproducts. In situ DRIFTS spectra verified that the amidation activation with visible light irradiation at 25 °C was much faster than heating.
- Jiang, Heyan,Hu, Zujie,Gan, Chuan,Sun, Bin,Kong, Shuzhen,Bian, Fengxia
-
-
- Method for catalyzing one-pot hydrogenation and amidation of nitroaromatic hydrocarbon and carboxylic acid by visible light
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The invention discloses a method for catalyzing one-pot hydrogenation and amidation reaction of nitroaromatic hydrocarbon and carboxylic acid by visible light. The method comprises the following steps: preparing Pt nanoparticles uniformly dispersed on an N-doped titanium dioxide/titanium carbide (MXene) heterojunction as a photocatalyst (3% Pt/N-TiO2/Ti3C2), and applying the catalyst to a cascade reaction of an aromatic nitro compound and carboxylic acid to prepare an amide product. The 3% Pt/N-TiO2/Ti3C2 has excellent tandem hydrogenation and amidation activity and chemical selectivity of an aromatic nitro compound and carboxylic acid under the irradiation of visible light. The excellent catalytic performance of 3% Pt/N-TiO2/Ti3C2 is attributed to the close contact of TiO2 and conductive Ti3C2, and the separation efficiency of photo-induced electrons and holes is improved through charge short-range directional transmission. The preparation method of the catalyst is simple and easy to operate, the catalyst can be used for photocatalytic efficient one-pot hydrogenation and amidation reactions, the reaction conditions are mild, and the catalyst is easy to recycle.
- -
-
Paragraph 0029
(2021/06/09)
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- Chemistry of Tertiary Carbon Center in the Formation of Congested C?O Ether Bonds
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Nucleophilic substitutions, including SN1 and SN2, are classical and reliable reactions, but a serious drawback is their intolerance for both bulky nucleophiles and chiral tertiary alkyl electrophiles for the synthesis of a chiral quaternary carbon center. An SRN1 reaction via a radical species is another conventional method used to carry out substitution reactions of bulky nucleophiles and alkyl halides, but chiral tertiary alkyl electrophiles cannot be used. Therefore, a stereospecific nucleophilic substitution reaction using chiral tertiary alkyl electrophiles and bulky nucleophiles has not yet been well studied. In this paper, we describe the reaction of tertiary alkyl alcohols and non-chiral or chiral α-bromocarboxamides as a tertiary alkyl source for the formation of congested ether compounds possessing two different tertiary alkyl groups on the oxygen atom with stereoretention.
- Hirata, Goki,Takeuchi, Kentarou,Shimoharai, Yusuke,Sumimoto, Michinori,Kaizawa, Hazuki,Nokami, Toshiki,Koike, Takashi,Abe, Manabu,Shirakawa, Eiji,Nishikata, Takashi
-
supporting information
p. 4329 - 4334
(2020/12/23)
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- Hypervalent Iodine Reagent-Promoted Hofmann-Type Rearrangement/Carboxylation of Primary Amides
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A novel transformation of primary amides to secondary amides promoted by hypervalent iodine reagents was developed. The hypervalent iodine reagent-mediated Hofmann-type rearrangement generated an isocyanate intermediate, which was subsequently trapped by an in situ generated carboxylic acid from the hypervalent iodine reagent to provide the corresponding secondary amides. This method provided a facile and efficient route for the synthesis of secondary amides from primary amides and also revealed novel reactivities of hypervalent iodine reagents.
- Wang, Xia,Yang, Peng,Hu, Bo,Zhang, Qian,Li, Dong
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p. 2820 - 2826
(2021/02/01)
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- Ligand-free copper-catalyzed direct amidation of diaryliodonium salts using nitriles as amidation reagents
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An efficient and practical methodology for the synthesis of N-arylamides has been developed via copper-catalyzed amidation of diaryliodonium salts with nitriles. Various substituted aryl nitriles and aliphatic nitriles could be applied in the reaction, providing a series of N-arylated amides in moderate to good yields. This procedure provides an alternative route for the synthesis of various N-arylamides. A proposed mechanism based on control experiments is also presented.
- Cheng, Hui-cheng,Guo, Penghu,Ji, Hong-bing,Ma, Jiao-li,Zhang, Yang,Zhou, Lichao,Zhou, Xuming
-
supporting information
(2021/04/19)
-
- Efficient nitriding reagent and application thereof
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The invention discloses an efficient nitriding reagent and application thereof, wherein the nitriding reagent comprises nitrogen oxide, an active agent, a reducing agent and an organic solvent. By applying the nitriding reagent, nitrogen-containing compounds such as amide, nitrile and the like can be produced, and the method is simple in condition, low in waste discharge amount and simple in reaction equipment.
- -
-
Paragraph 0076-0100
(2021/03/31)
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- Ethyl 2-Cyano-2-(2-nitrobenzenesulfonyloxyimino) Acetate (ortho-NosylOXY)-Mediated Double Beckmann Rearrangement of Ketoximes under Microwave Irradiation: A Mechanistic Perception
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A method for Beckmann rearrangement using ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino) acetate (o-NosylOXY) under microwave irradiation is reported. Ketoximes (19 examples) are converted to the corresponding amides/lactams with 69–97% yields in ~10 minutes without any Lewis acid or co-catalyst. This is an example of halogen-free organocatalytic Beckmann rearrangement. Nuclear magnetic resonance (NMR)- and high-resolution mass spectrometry (HRMS)-based detailed mechanistic investigation suggest that o-NosylOXY acts as an initiator. Such initiators are reported before based on density functional theory (DFT) calculations. However, we report here the HRMS signatures of two transient intermediates, the nitrilium ion and the nitrilium ion's dimeric species. Rigorous NMR-based investigation of the reaction mechanism is performed. Our results indicate that the reported Beckmann rearrangement proceeds via two consecutive rearrangements. (Figure presented.).
- Dev, Dharm,Kalita, Tapasi,Mondal, Tanmay,Mandal, Bhubaneswar
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p. 1427 - 1435
(2021/01/04)
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- Preparation method of amide
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The invention relates to a preparation method of an amide, wherein, under the action of oxygen, the isothiocyanate and the aldehyde can react to form an amide, and the reaction temperature can be effectively increased only when not less than 110 °C. This process is also suitable for the reaction of isocyanates with aldehydes to produce amides. The preparation method is cheap in raw material, wide in substrate application range and free of metal catalysts in the reaction process. The initiator or other activator is green and economical, and can effectively reduce the cost.
- -
-
Paragraph 0055-0079; 0164-0169
(2021/08/25)
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- Asymmetric Markovnikov Hydroaminocarbonylation of Alkenes Enabled by Palladium-Monodentate Phosphoramidite Catalysis
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A palladium-catalyzed asymmetric Markovnikov hydroaminocarbonylation of alkenes with anilines has been developed for the atom-economical synthesis of 2-substituted propanamides bearing an α-stereocenter. A novel phosphoramidite ligand L16 was discovered which exhibited very high reactivity and selectivity in the reaction. This asymmetric Markovnikov hydroaminocarbonylation employs readily available starting materials and tolerates a wide range of functional groups, thus providing a facile and straightforward method for the regio- and enantioselective synthesis of 2-substituted propanamides under ambient conditions. Mechanistic studies revealed that the reaction proceeds through a palladium hydride pathway.
- Yao, Ya-Hong,Yang, Hui-Yi,Chen, Ming,Wu, Fei,Xu, Xing-Xing,Guan, Zheng-Hui
-
supporting information
p. 85 - 91
(2021/01/12)
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- Para -Selective copper-catalyzed C(sp2)-H amidation/dimerization of anilides via a radical pathway
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Copper-catalyzed amidation/dimerization of anilides via regioselective C(sp2)-H functionalization is achieved. The para-selective amidation is accomplished on the anilide aromatic ring via a radical pathway leading to C-N bond formation in the presence of ammonium persulfate as a radical source/oxidant for the copper catalyst. The developed protocol tolerates a wide range of anilide substrates. The regioselectivity is confirmed by single-crystal X-ray studies.
- Viveki, Amol B.,Garad, Dnyaneshwar N.,Gonnade, Rajesh G.,Mhaske, Santosh B.
-
supporting information
p. 1565 - 1568
(2020/02/13)
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- Preparation method of N-aryl amide compound
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The invention discloses a preparation method of an N-aryl amide compound, which comprises the following steps: (1) putting diaryliodonium salt and Cu(OAc)2 into a Schlenk tube provided with a magneticstirring rod; (2) sequentially adding DCE, H2O and nitrile by using an injector, sealing the Schlenk tube, and stirring for reaction at 80 DEG C; (3) cooling the obtained solution to room temperature, and performing extraction with EtOAc; and combining organic layers, performing washing with saline water, and performing drying with anhydrous Na2SO4; and (4) removing volatile matters in vacuum, and purifying residues through column chromatography to obtain the N-aryl amide compound. Through a large number of experiments, a substrate with a simple structure is screened, the reaction conditionsare mild, the yield is high, the pollution is small, and the application prospect is wide.
- -
-
Paragraph 0092-0097
(2020/07/13)
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- Nitromethane as a nitrogen donor in Schmidt-type formation of amides and nitriles
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The Schmidt reaction has been an efficient and widely used synthetic approach to amides and nitriles since its discovery in 1923. However, its application often entails the use of volatile, potentially explosive, and highly toxic azide reagents. Here, we report a sequence whereby triflic anhydride and formic and acetic acids activate the bulk chemical nitromethane to serve as a nitrogen donor in place of azides in Schmidt-like reactions. This protocol further expands the substrate scope to alkynes and simple alkyl benzenes for the preparation of amides and nitriles.
- Jiao, Ning,Liu, Jianzhong,Qiu, Xu,Song, Song,Wei, Jialiang,Wen, Xiaojin,Zhang, Cheng,Zhang, Ziyao
-
supporting information
p. 281 - 285
(2020/01/28)
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- Direct synthesis of secondary amides from ketones through Beckmann rearrangement using O-(mesitylsulfonyl)hydroxylamine
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The Beckmann rearrangement is a versatile method for the preparation of secondary amides from ketones via oxime intermediates and has been widely used in the synthesis of bioactive natural products and pharmaceuticals. Herein, we have developed a highly efficient direct method for the preparation of secondary amides and lactams from ketones using O-(mesitylsulfonyl)hydroxylamine (MSH). The reactions proceed rapidly at room temperature under mild condition without requiring any additive, and tolerate multiple functional groups. A simple aqueous work-up often furnished the products in excellent yield with high purity.
- Chandra, Dinesh,Verma, Saumya,Pandey, Chandra Bhan,Yadav, Ajay K.,Kumar, Puneet,Tiwari, Bhoopendra,Jat, Jawahar L.
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supporting information
(2020/03/23)
-
- Sulfuryl Fluoride Mediated Synthesis of Amides and Amidines from Ketoximes via Beckmann Rearrangement
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A metal-free and redox-neutral method for Beckmann rearrangement employing inexpensive and readily available SO2F2 gas is described. The reported transformation proceeds at ambient temperature and is compatible with a wide range of sterically and electronically diverse aromatic, heteroaromatic, aliphatic and lignin-like oximes providing amides in good to excellent yields. The reaction proceeds through the formation of an imidoyl fluoride intermediate that can also be used for the synthesis of amidines.
- Gurjar, Jitendra,Fokin, Valery V.
-
supporting information
p. 10402 - 10405
(2020/07/25)
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- Visible-light-induced Beckmann rearrangement by organic photoredox catalysis
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A facile and general strategy for efficient direct conversion of oximes to amides using an inexpensive organic photocatalyst and visible light is described. This radical Beckmann rearrangement can be performed under mild conditions. Various alkyl aryl ketoximes and diaryl ketoximes can be effectively converted into the corresponding amides in excellent yields.
- Tang, Li,Wang, Zhi-Lv,Wan, Hai-Lan,He, Yan-Hong,Guan, Zhi
-
supporting information
p. 6182 - 6186
(2020/09/01)
-
- An Electrochemical Beckmann Rearrangement: Traditional Reaction via Modern Radical Mechanism
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Abstract: Electrosynthesis as a potential means of introducing heteroatoms into the carbon framework is rarely studied. Herein, the electrochemical Beckmann rearrangement, i. e. the direct electrolysis of ketoximes to amides, is presented for the first time. Using a constant current as the driving force, the reaction can be easily carried out under neutral conditions at room temperature. Based on a series of mechanistic studies, a novel radical Beckmann rearrangement mechanism is proposed. This electrochemical Beckmann rearrangement does not follow the trans-migration rule of the classical Beckmann rearrangement.
- Tang, Li,Wang, Zhi-Lv,He, Yan-Hong,Guan, Zhi
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p. 4929 - 4936
(2020/08/21)
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- Copper-Catalyzed Electrophilic Amidation of Organotrifluoroborates with Use of N-Methoxyamides
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A copper-catalyzed electrophilic amidation of aryltrifluoroborates with use of N-methoxyamides is reported. The reaction shows high functional group compatibility derived from two distinct features: 1) the high stability of the N-methoxyamides and 2) the nonbasic mild conditions in the presence of LiCl. The developed method can also be applied to the synthesis of enamides, which are widely distributed in natural products. Preliminary mechanistic studies suggest that the initial step is the transmetalation of the aryltrifluoroborate by the assistance of LiCl, and the resulting aryl copper intermediate provides the anilide through non-SN2 oxidative addition to the N-methoxyamide and subsequent reductive elimination.
- Banjo, Shona,Nakasuji, Eiko,Meguro, Tatsuhiko,Sato, Takaaki,Chida, Noritaka
-
supporting information
p. 7941 - 7947
(2019/05/24)
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- Amide Synthesis from Thiocarboxylic Acids and Amines by Spontaneous Reaction and Electrosynthesis
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Amide bond formation is one of the most important basic reactions in chemistry. A catalyst-free approach for constructing amide bonds from thiocarboxylic acids and amines was developed. The mechanistic studies showed that the disulfide was the key intermediate for this amide synthesis. Thiobenzoic acids could be automatically oxidized to disulfides in air, thioaliphatic acids could be electro-oxidized to disulfides, and the resulting disulfides reacted with amines to give the corresponding amides. By this method, various amides could be easily synthesized in excellent yields without using any catalyst or activator. The successful synthesis of bioactive compounds also highlights the synthetic utility of this strategy in medicinal chemistry.
- Tang, Li,Matuska, Jack H.,Huang, Yu-Han,He, Yan-Hong,Guan, Zhi
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p. 2570 - 2575
(2019/06/13)
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- Chromium-Catalyzed Activation of Acyl C-O Bonds with Magnesium for Amidation of Esters with Nitroarenes
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Here, we report a chromium-catalyzed activation of acyl C-O bonds with magnesium for amidation of esters with nitroarenes. Low-cost chromium(III) chloride shows high reactivity in promoting amidation by using magnesium as reductant and chlorotrimethylsilane as additive. It provides a step-economic strategy to the synthesis of centrally important amide motifs using inexpensive and air-stable nitroarenes as amino sources.
- Ling, Liang,Chen, Changpeng,Luo, Meiming,Zeng, Xiaoming
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supporting information
(2019/03/19)
-
- Cu(OTf) 2 -Catalyzed Beckmann Rearrangement of Ketones Using Hydroxylamine- O -sulfonic Acid (HOSA)
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The Beckmann rearrangement (BKR) of ketones to secondary amides often requires harsh reaction conditions that limit its practicality and scope. Herein, the Cu(OTf) 2 -catalyzed BKR of ketones under mild reaction conditions using hydroxylamine- O -sulfonic acid (HOSA), a commercial water soluble aminating agent, is described. This method is compatible with most functional groups and directly provides the desired amides in good to excellent yields.
- Anugu, Raghunath Reddy,Chandra, Dinesh,Falck, John R.,Jat, Jawahar L.,Munnuri, Sailu,Verma, Saumya
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p. 3709 - 3714
(2019/09/30)
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- Palladium(II)-Catalyzed Oxidative Homo- and Cross-Coupling of Aryl ortho -sp2 C-H Bonds of Anilides at Room Temperature
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The preparation of secondary 2,2'-bisanilides has been successfully achieved through an oxidative coupling of aryl ortho-sp2 C-H bonds of anilides in the presence of catalytic Pd(OAc)2 and K2S2O8 as an oxidant in MsOH/CF3CO2H (TFA) at room temperature (25 °C). The aromatic rings of anilides substituted by various electron-donating or electron-withdrawing groups are tolerant in these coupling reactions.
- Mei, Chong,Lu, Wenjun
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p. 4812 - 4823
(2018/04/26)
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- α-Tetrasubstituted Aldehydes through Electronic and Strain-Controlled Branch-Selective Stereoselective Hydroformylation
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Hydroformylation utilizes dihydrogen, carbon monoxide, and a catalyst to transform alkenes into aldehydes. This work applies chiral bisdiazaphospholane (BDP)- and bisphospholanoethane-ligated rhodium complexes to the hydroformylation of a variety of alkenes to produce chiral tetrasubstituted aldehydes. 1,1′-Disubstituted acrylates bearing electron-withdrawing substituents undergo hydroformylation under mild conditions (1 mol % of catalyst/BDP ligand, 150 psig gas, 60 °C) with high conversions and yields of tetrasubstituted aldehydes (e.g., 13:1 regioselectivity, 85% ee, and 99% regioselectivity and >19:1 diastereoselectivity to tetrasubstituted aldehydes at rates >50 catalyst turnovers/hour. NMR studies of the noncatalytic reaction of HRh(BDP)(CO)2 with methyl 1-fluoroacrylate enable interception of tertiary alkylrhodium intermediates, demonstrating migratory insertion to acyl species is slower than formation of secondary and primary alkylrhodium intermediates. Overall, these investigations reveal how the interplay of sterics, electronics, and ring strain are harnessed to provide access to valuable α-tetrasubstituted aldehyde synthetic building blocks by promoting branched-selective hydroformylation.
- Eshon, Josephine,Foarta, Floriana,Landis, Clark R.,Schomaker, Jennifer M.
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p. 10207 - 10220
(2018/09/06)
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- Direct and Catalytic Amide Synthesis from Ketones via Transoximation and Beckmann Rearrangement under Mild Conditions
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The Br?nsted acid-catalyzed synthesis of secondary amides from ketones under mild conditions is described via transoximation and Beckmann rearrangement using O-protected oximes as more stable equivalents of explosive O-protected hydroxylamines. This methodology could be applied to highly rearrangement-selective amide synthesis from α-branched alkyl aryl ketones and performed on a 1-g scale. The presence of water is essential for this reaction, and its role was clarified by isotope-labeling experiments.
- Hyodo, Kengo,Hasegawa, Genna,Oishi, Naoki,Kuroda, Kazuma,Uchida, Kingo
-
supporting information
p. 13080 - 13087
(2018/11/02)
-
- Scope and mechanism of a true organocatalytic beckmann rearrangement with a boronic acid/perfluoropinacol system under ambient conditions
-
Catalytic activation of hydroxyl functionalities is of great interest for the production of pharmaceuticals and commodity chemicals. Here, 2-alkoxycarbonyl- and 2-phenoxycarbonyl-phenylboronic acid were identified as efficient catalysts for the direct and chemoselective activation of oxime N-OH bonds in the Beckmann rearrangement. This classical organic reaction provides a unique approach to prepare functionalized amide products that may be difficult to access using traditional amide coupling between carboxylic acids and amines. Using only 5 mol % of boronic acid catalyst and perfluoropinacol as an additive in a polar solvent mixture, the operationally simple protocol features mild conditions, a broad substrate scope, and a high functional group tolerance. A wide variety of diaryl, aryl-alkyl, heteroaryl-alkyl, and dialkyl oximes react under ambient conditions to afford high yields of amide products. Free alcohols, amides, carboxyesters, and many other functionalities are compatible with the reaction conditions. Investigations of the catalytic cycle revealed a novel boron-induced oxime transesterification providing an acyl oxime intermediate involved in a fully catalytic nonself-propagating Beckmann rearrangement mechanism. The acyl oxime intermediate was prepared independently and was subjected to the reaction conditions. It was found to be self-sufficient; it reacts rapidly, unimolecularly without the need for free oxime. A series of control experiments and 18O labeling studies support a true catalytic pathway involving an ionic transition structure with an active and essential role for the boronyl moiety in both steps of transesterification and rearrangement. According to 11B NMR spectroscopic studies, the additive perfluoropinacol provides a transient, electrophilic boronic ester that is thought to serve as an internal Lewis acid to activate the ortho-carboxyester and accelerate the initial, rate-limiting step of transesterification between the precatalyst and the oxime substrate.
- Mo, Xiaobin,Morgan, Timothy D. R.,Ang, Hwee Ting,Hall, Dennis G.
-
supporting information
p. 5264 - 5271
(2018/04/24)
-
- Amine Activation: Synthesis of N-(Hetero)arylamides from Isothioureas and Carboxylic Acids
-
A novel method for N-(hetero)arylamide synthesis based on rarely explored amine activation, rather than classical acid activation, is reported. The activated amines are easily prepared using a three-component reaction with commercial reagents. The new method shows a broad scope including challenging amides not (efficiently) accessible via classical protocols.
- Zhu, Yan-Ping,Sergeyev, Sergey,Franck, Philippe,Orru, Romano V. A.,Maes, Bert U. W.
-
supporting information
p. 4602 - 4605
(2016/09/28)
-
- Intramolecular 1,5-H transfer reaction of aryl iodides through visible-light photoredox catalysis: A concise method for the synthesis of natural product scaffolds
-
The intramolecular 1,5-H transfer reaction of the aryl radicals generated from unactivated aryl iodides by photocatalysis is described. The features of this transformation are operational simplicity, excellent yields, mild reaction conditions, and good fu
- Chen, Jian-Qiang,Wei, Yun-Long,Xu, Guo-Qiang,Liang, Yong-Min,Xu, Peng-Fei
-
p. 6455 - 6458
(2016/05/24)
-
- Potassium Thioacids Mediated Selective Amide and Peptide Constructions Enabled by Visible Light Photoredox Catalysis
-
A remarkable visible-light-promoted photoredox catalytic methodology involved with amines and eco-friendly potassium thioacids for amide formation was uncovered. This approach can mimic the natural coenzyme acetyl-CoA to selectively acylate amines without affecting other functional groups such as alcohols, phenols, esters, among others. The developed strategy may hold great potential for a comprehensive display of biologically interesting peptide synthesis and amino acid modification through a diacyl disulfide intermediate.
- Liu, Hongxin,Zhao, Liyun,Yuan, Yunfei,Xu, Zhifang,Chen, Kai,Qiu, Shengxiang,Tan, Haibo
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p. 1732 - 1736
(2016/03/15)
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- Base-catalyzed synthesis of aryl amides from aryl azides and aldehydes
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Aryl amides have been used as important compounds in pharmaceuticals, materials and in molecular catalysis. The methods reported to prepare aryl amides generally require very specific reagents, and the most popular carboxyl-amine coupling reactions demand stoichiometric activators. Herein, we report that aryl azides react with aldehydes under base-catalyzed conditions to yield aryl amides efficiently. Mechanistic investigations support the formation of triazoline intermediates via azide-enolate cycloaddition, which subsequently undergo rearrangement to give amides by either thermal decomposition (20-140 °C) or aqueous acid work-up at room temperature. The strategy does not require nucleophilic anilines and is especially efficient for highly electron-deficient aryl amides, including perfluoroaryl amides, which are otherwise challenging to synthesize.
- Xie, Sheng,Zhang, Yang,Ramstr?m, Olof,Yan, Mingdi
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p. 713 - 718
(2015/12/30)
-
- Palladium-Catalyzed Synthesis of Aryl Amides through Silanoate-Mediated Hydrolysis of Nitriles
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A procedure for the formation of aryl amides through the palladium-catalyzed coupling of nitriles and aryl bromides, via the formation of intermediary silanoate derived imidate species is reported. Optimization was undertaken and examples of the process are described that furnish the products in up to 86% isolated yield.
- McPherson, Christopher G.,Livingstone, Keith,Jamieson, Craig,Simpson, Iain
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supporting information
p. 88 - 92
(2015/12/26)
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- Metal-free n -arylation of secondary amides at room temperature
-
The arylation of secondary acyclic amides has been achieved with diaryliodonium salts under mild and metal-free conditions. The methodology has a wide scope, allows synthesis of tertiary amides with highly congested aryl moieties, and avoids the regioselectivity problems observed in reactions with (diacetoxyiodo)benzene.
- Tinnis, Fredrik,Stridfeldt, Elin,Lundberg, Helena,Adolfsson, Hans,Olofsson, Berit
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supporting information
p. 2688 - 2691
(2015/06/16)
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- Comparative Catalytic Activity of Group 9 [CpMIII] Complexes: Cobalt-Catalyzed C-H Amidation of Arenes with Dioxazolones as Amidating Reagents
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A procedure for the [CpCoIII]-catalyzed direct C-H amidation of arenes with dioxazolone has been developed. This reaction proceeds under straightforward and mild conditions with a broad range of substrates, including anilides. A comparative study on the catalytic activity of Group 9 [{CpMCl2}2] complexes revealed the unique efficiency of the cobalt catalyst. Pick of the bunch: A variety of arenes, including anilides, underwent direct C-H amidation with dioxazolones in the presence of a cobalt catalyst with a Cp? ligand under mild and straightforward reaction conditions (see scheme; Piv=pivaloyl). A comparative study of Group 9 [CpMIII] complexes revealed the unique ability of the cobalt catalyst to promote this transformation efficiently.
- Park, Juhyeon,Chang, Sukbok
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supporting information
p. 14103 - 14107
(2016/01/25)
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- An Iron-Catalyzed Direct Approach to Amides from Benzyl Azides via C-C Bond Cleavage
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A novel iron-catalyzed transformation of benzyl azides to give the corresponding amides via C-C bond cleavage under mild reaction conditions is developed. This method provides a new synthetic tool for the construction of amides and the opportunity to accomplish C-C functionalization under mild conditions.
- Ou, Yang,Qin, Chong,Song, Song,Jiao, Ning
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p. 2971 - 2975
(2015/09/28)
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- Mild and Efficient Cobalt-Catalyzed Cross-Coupling of Aliphatic Amides and Aryl Iodides in Water
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A convenient protocol for the C-N cross-coupling of aliphatic amides and iodobenzene is demonstrated using a simple and inexpensive Co(C2O4)·2H2O/N,N′-dimethylethylenediamine (DMEDA) catalytic system in water. Good yields of N-arylated products were isolated (up to 85%) and the protocol has been successfully applied to the synthesis of the anticancer drug, flutamide.
- Tan, Bryan Yong-Hao,Teo, Yong-Chua
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supporting information
p. 1697 - 1701
(2015/07/20)
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- Microwave-assisted heteropolyanion-based ionic liquids catalyzed transamidation of non-activated carboxamides with amines under solvent-free conditions
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An environmentally benign and highly efficient protocol for the transamidation of non-activated carboxamides with amines using heteropolyanion-based ionic liquids as catalysts under microwave-assisted and solvent-free conditions has been developed. As evaluated by the reactions of a structurally diverse set of amides and amines, the scope and utility of the transamidation proved to be quite general. Operational simplicity, solvent-free media, the potential reusability of catalysts and wide functional group tolerance are attractive features. This method provides a much improved protocol over the existing methods.
- Fu, Renzhong,Yang, Yang,Chen, Zhikai,Lai, Wenchen,Ma, Yongfeng,Wang, Quan,Yuan, Rongxin
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p. 9492 - 9499
(2015/03/04)
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- One-pot oximation-Beckmann rearrangement of ketones and aldehydes to amides of industrial interest: Acetanilide, caprolactam and acetaminophen
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High yielding one-pot oximation-Beckmann rearrangement of ketones to amides in ktrifluoroacetic acid has been conducted on several ketones and aldehydes. The substrate reactivity showed to depend on both oximation and Beckmann rearrangement reaction rate. In this synthetic procedure, trifluoroacetic acid acts as solvent, acid catalyst and organocatalyst and can be easily recycled.
- Aricò, Fabio,Quartarone, Giuseppe,Rancan, Elia,Ronchin, Lucio,Tundo, Pietro,Vavasori, Andrea
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- Aerobic oxidative transformation of primary alcohols and amines to amides promoted by a hydroxyapatite-supported gold catalyst in water
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In the presence of an easily prepared hydroxyapatite-supported gold catalyst, namely Au/HAP, various kinds of structurally diverse primary alcohols including benzylic and aliphatic ones, and amines involving aromatic and secondary ones could be converted into the corresponding amides in water with up to 99% yield. Meanwhile, on the basis of experimental observations and literatures, a plausible reaction pathway was described to elucidate the reaction mechanism.
- Wang, Wentao,Cong, Yu,Zhang, Leilei,Huang, Yanqiang,Wang, Xiaodong,Zhang, Tao
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supporting information
p. 124 - 127
(2014/01/06)
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- Reductive acylation of nitroarenes to anilides by sodium sulfite in carboxylic acids
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A facile and efficient reductive acylation of aromatic nitro compounds to corresponding anilides using a sodium sulfite-carboxylic acid system for the first time has been reported. The sodium sulfite reagent provides the colorless reductant in combination with stoichiometric amounts of carboxylic acid and enables the formation of anilides from nitroarenes without any additives in good to excellent yields with high purities and simple work-up. Furthermore, this protocol provides a novel and complementary access to some industrially important chemicals in kilogram scale under mild conditions.
- Ghaffarzadeh, Mohammad,Akhavan, Pegah
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supporting information
p. 1417 - 1419
(2016/09/28)
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- Synthesis and pharmacological evaluation of 6-arylpyridazinones as potent vasorelaxants
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Preclinical Research As part of a research program to identify compounds with potent antihypertensive properties, a new series of dihydropyridazin-3(2H)- one analogs was synthesized and evaluated for vasodilator activity in rat thoracic aortic rings. Most
- Bansal, Ranju,Kumar, Dinesh,Sharma, Deepika,Calle, Carmen,Carron, Rosalia
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p. 296 - 305
(2013/08/23)
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- Aerobic oxidative coupling of alcohols and amines over Au-Pd/resin in water: Au/Pd molar ratios switch the reaction pathways to amides or imines
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A facile switch of the reaction pathways of aerobic oxidative coupling of alcohols and amines from amidation to imination was realized for the first time by tuning the Au/Pd ratios in ion-exchange resin supported Au-Pd alloy catalysts (Au-Pd/resin). Amides were obtained with high yields on Au6Pd/resin while imines were obtained over AuPd4/resin. Various alcohols and amines underwent oxidative coupling smoothly in water to afford the desired products with good to excellent yields. Further investigation on the reaction mechanism suggested the synergistic effect between Au and Pd determined the adsorption strength of the aldehyde intermediate, which in turn dictated the reaction pathways. That is, on Au-rich alloys (e.g., Au6Pd) absorbed aldehyde species was formed, followed by further oxidation to yield amides, while on Pd-rich alloys (e.g., AuPd4), free aldehyde was generated, which then underwent condensation with amines to produce imines. The discovery might provide avenues to develop new efficient catalysts for the green synthesis of special chemicals.
- Zhang, Leilei,Wang, Wentao,Wang, Aiqin,Cui, Yitao,Yang, Xiaofeng,Huang, Yanqiang,Liu, Xiaoyan,Liu, Wengang,Son, Jin-Young,Oji, Hiroshi,Zhang, Tao
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p. 2680 - 2684
(2013/10/08)
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- Synthesis of N-arylamides by copper-catalyzed amination of aryl halides with nitriles
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A copper-catalyzed amination of aryl halides with nitriles has been developed. The use of nitriles as nitrogen nucleophiles can make the synthesis of N-arylamides more simple than that using amides through in-situ hydrolysis. A variety of N-arylamides and benzoxazole derivatives can be synthesized according to this approach. Copyright
- Xiang, Shi-Kai,Zhang, Dong-Xue,Hu, Hao,Shi, Jiang-Ling,Liao, Li-Guo,Feng, Chun,Wang, Bi-Qin,Zhao, Ke-Qing,Hu, Ping,Yang, Hua,Yu, Wen-Hao
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supporting information
p. 1495 - 1499
(2013/06/27)
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- An improved protocol for synthesis of N-arylamides and benzoxazoles by the copper-catalyzed reaction of aryl halides with nitriles
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An improved protocol for the synthesis of N-arylamides and benzoxazoles by the copper-catalyzed reaction of aryl halides with nitriles has been developed. Use of acetaldoxime as the hydrolysis reagent instead of H2O facilitates the operation of the reaction. The significantly decreased amount of nitriles, along with use of weak base K2CO3 instead of strong base KOH, makes this transformation atom-efficient and environmentally benign. A variety of N-arylamides and benzoxazole derivatives can be synthesized according to this approach.
- Zhang, Dong-Xue,Xiang, Shi-Kai,Hu, Hao,Tan, Wen,Feng, Chun,Wang, Bi-Qin,Zhao, Ke-Qing,Hu, Ping,Yang, Hua
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p. 10022 - 10029
(2013/11/06)
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- Tert-butoxide-assisted amidation of esters under green conditions
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Efficient and green amidation reactions are of great importance. In this work, we demonstrate the tert-butoxide-assisted amidation of esters with amines under ambient conditions. Aliphatic and/or aromatic esters were converted into the corresponding amides under mild conditions in good to excellent yields. It is noteworthy that the reaction is highly efficient, rapid, versatile, green and economical, and will find great practical application in organic synthesis, biochemistry, and industrial chemistry. Georg Thieme Verlag Stuttgart. New York.
- Kim, Bo Ram,Lee, Hyung-Geun,Kang, Seung-Beom,Sung, Gi Hyeon,Kim, Jeum-Jong,Park, Jong Keun,Lee, Sang-Gyeong,Yoon, Yong-Jin
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experimental part
p. 42 - 50
(2012/03/26)
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- Titanium cation-exchanged montmorillonite as an active heterogeneous catalyst for the Beckmann rearrangement under mild reaction conditions
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Titanium cation-exchanged montmorillonite acts as an efficient heterogeneous catalyst for the Beckmann rearrangement of a wide range of ketoximes including aromatic, aliphatic, and alicyclic ketoximes under mild reaction conditions. After the rearrangement reaction, titanium cation-exchanged montmorillonite is easily separated by simple filtration, and can be reused with retention of high efficiency.
- Mitsudome, Takato,Matsuno, Tsuyoshi,Sueoka, Shoichiro,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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supporting information
p. 5211 - 5214
(2012/11/07)
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- ORGANOMETALLIC COMPLEX, LIGHT-EMITTING ELEMENT, DISPLAY DEVICE, ELECTRONIC DEVICE, AND LIGHTING DEVICE
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Provided are organometallic complexes that can exhibit phosphorescence. One of the novel organometallic complexes is represented by General Formula (G1). In General Formula (G1), R1 represents any of an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms which may have a substituent, and an aralkyl group having 7 to 10 carbon atoms which may have a substituent. In addition, R2 represents any of an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms which may have a substituent, and an aryl group having 6 to 12 carbon atoms which may have a substituent. Further, Ar represents an arylene group having 6 to 13 carbon atoms which may have a substituent. Further, M represents a Group 9 element or a Group 10 element.
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Page/Page column 104
(2011/05/11)
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- Palladium-catalyzed oxidative C-H bond coupling of steered acetanilides and aldehydes: A facile access to ortho -acylacetanilides
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A palladium-catalyzed oxidative C-H bond functionalization/ortho-acylation of acetanilides using easily accessible aldehyde as the acyl source is described. In the presence of a Pd(TFA)2 catalyst and tert-butylhydroperoxide at 90 °C in general, an array of ortho-acylacetanilides can be afforded in good yields.
- Wu, Yinuo,Li, Baozhu,Mao, Fei,Li, Xingshu,Kwong, Fuk Yee
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supporting information; experimental part
p. 3258 - 3261
(2011/08/05)
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- Beckmann rearrangement of oximes using pivaloyl chloride/DMF complex
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A new complex of pivaloyl chloride and DMF was found to be very effective for converting ketoximes into their corresponding amides or lactams with excellent conversion via the Beckmann rearrangement. This method offers significant advantages such as efficiency and mild reaction conditions with shorter reaction time.
- Narahari, Srinivasa Reddy,Reguri, Buchi Reddy,Mukkanti
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experimental part
p. 4888 - 4891
(2011/10/05)
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