- Pd-Catalyzed Carbonylative Synthesis of 4H-Benzo[d][1,3]Oxazin-4-Ones Using Benzene-1,3,5-Triyl Triformate as the CO Source
-
A facile synthesis of 4H-benzo[d][1,3]oxazin-4-one derivatives by Pd-catalyzed carbonylative cross-coupling between N-(ortho-bromoaryl)amides and benzene-1,3,5-triyl triformate (TFBen) was developed. This procedure does not require the toxic and flammable gas CO as the carbonyl source and tolerates a wide scope of functional groups. Remarkably, 4H-benzo[d][1,3]oxazin-4-ones incorporated to natural products and drugs can be constructed by this method.
- Zheng, Yan,Dong, Mengke,Qu, Erdong,Bai, Jin,Wu, Xiao-Feng,Li, Wanfang
-
supporting information
p. 16219 - 16224
(2021/10/06)
-
- Novel and efficient heterogeneous polymer supported copper catalyst for synthesis of 2-substituted Benzoxazoles from 2-Haloanilides
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A novel polymer supported copper complex is prepared by the immobilization of copper iodide on chemically modified polyacrylonitrile and its application in heterogeneous catalysis is described. The catalyst was prepared by easy method via synthetic modification of Polyacrylonitrile (PAN) using ethylene diamine followed by the complexation with CuI. After characterization, this complex was explored as a green and efficient heterogeneous catalyst for the synthesis of 2-benzoxazoles from 2-haloanilides. The reaction was performed without adding additional ligand and the catalyst shows activity over a broad range of substrates with quantitative product yields. The catalyst was easily recovered by simple filtration and reused successfully for further cycle.
- Saranya, Thachora Venu,Sruthi, Pambingal Rajan,Raj, Veena,Anas, Saithalavi
-
supporting information
(2021/02/27)
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- Photocatalyst- And Transition-Metal-Free Visible-Light-Promoted Intramolecular C(sp2)-S Formation
-
A photocatalyst- and transition-metal-free visible-light-induced cyclization of ortho-halothiobenzanilides has been developed. Upon irradiation with visible light, substrates undergo dehalogenative cyclization to 2-aryl benzothiazoles with high efficiency and selectivity. This photocyclization exhibits a high tolerance to various functional groups, is applicable for the synthesis of 2-alkyl benzothiazoles, and is easy to set up for gram-scale reaction.
- Wang, Hao,Wu, Qi,Zhang, Jian-Dong,Li, Hai-Yan,Li, Hong-Xi
-
supporting information
p. 2078 - 2083
(2021/04/05)
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- Acetonitrile and benzonitrile as versatile amino sources in copper-catalyzed mild electrochemical C-H amidation reactions
-
A mild, efficient electrochemical approach to the site-selective direct C-H amidation of benzene and its derivatives with acetonitrile and benzonitrile has been developed. It has been shown that joint electrochemical oxidation of various arenes in the presence of a copper salt as a catalyst and nitriles leads to the formation of N-phenylacetamide from benzene and N-benzylacetamides from benzyl derivatives (up to 78% yield). A favorable feature of the process is mild conditions (room temperature, ambient pressure, no strong oxidants) that meet the criteria of green chemistry.
- Budnikova, Yulia,Kononov, Alexander,Rizvanov, Ildar,Strekalova, Sofia
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p. 37540 - 37543
(2021/12/07)
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- Iron-catalyzed oxidative amidation of acylhydrazines with amines
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A new approach for amide bond formation via a mild and efficient Iron-catalyzed cross-coupling reaction of acylhydrazines and amines using TBHP as oxidant is described. This protocol is compatible with a wide range of amines and acylhydrazines. In addition, the synthetic application of the reaction is presented.
- Wang, Yi-Jie,Zhang, Guo-Yu,Shoberu, Adedamola,Zou, Jian-Ping
-
-
- Practical bromination of arylhydroxylamines with SOBr2 towards ortho-bromo-anilides
-
A facile approach for synthesizing ortho-bromoanilides from readily available aryhydroxylamines and thionyl bromide is demonstrated in this work. Mild reaction conditions and broad scope of substrates ranging from heterocyclic structures to pharmaceutics-potential motifs are used in the reactions of this paper. Efficient bromination of ortho C–H bonds of the aryhydroxylamines has been achieved. Ortho-bromoanilide products were obtained in good to excellent yields, and model scaled-up reactions of this synthetic approach are shown in this work.
- Du, Yuanbo,Feng, Lei,Gao, Hongyin,Guo, Lirong,Lu, Haifeng,Xi, Zhenguo
-
-
- Synthesis of 2-Amino-1,3-dienes from Propargyl Carbonates via Palladium-Catalyzed Carbon-Nitrogen Bond Formation
-
A catalytic method to synthesize 1,3,-dienes from propargylic precursors is reported. This palladium-catalyzed carbon-nitrogen bond-forming reaction furnishes 2-amino-1,3-dienes in excellent yields (up to 98%) and shows a broad tolerance to functional group diversity. The reaction has been demonstrated for over 30 amine substrates, including anilines and indoles, and proceeds under mild neutral conditions. The resulting 1,3-dienes are of great synthetic interest because of their further reaction potential.
- O'Broin, Calvin Q.,Guiry, Patrick J.
-
supporting information
p. 879 - 883
(2020/02/04)
-
- Copper-Catalyzed Modular Amino Oxygenation of Alkenes: Access to Diverse 1,2-Amino Oxygen-Containing Skeletons
-
Copper-catalyzed alkene amino oxygenation reactions using O-acylhydroxylamines have been achieved for a rapid and modular access to diverse 1,2-amino oxygen-containing molecules. This transformation is applicable to the use of alcohols, carbonyls, oximes, and thio-carboxylic acids as nucleophiles on both terminal and internal alkenes. Mild reaction conditions tolerate a wide range of functional groups, including ether, ester, amide, carbamate, and halide. The reaction protocol allows for starting with free amines as the precursor of O-benzoylhydroxylamines to eliminate their isolation and purification, contributing to broader synthetic utilities. Mechanistic investigations reveal the amino oxygenation reactions may involve distinct pathways, depending on different oxygen nucleophiles.
- Hemric, Brett N.,Chen, Andy W.,Wang, Qiu
-
supporting information
p. 1468 - 1488
(2019/01/25)
-
- Exogenous Photosensitizer-, Metal-, and Base-Free Visible-Light-Promoted C-H Thiolation via Reverse Hydrogen Atom Transfer
-
Visible-light-driven, intramolecular C(sp2)-H thiolation has been achieved without addition of a photosensitizer, metal catalyst, or base. This reaction induces the cyclization of thiobenzanilides to benzothiazoles. The substrate absorbs visible light, and its excited state undergoes a reverse hydrogen-atom transfer (RHAT) with 2,2,6,6-tetramethylpiperidine N-oxyl to form a sulfur radical. The addition of the sulfur radical to the benzene ring gives an aryl radical, which then rearomatizes to benzothiazole via RHAT.
- Xu, Ze-Ming,Li, Hong-Xi,Young, David James,Zhu, Da-Liang,Li, Hai-Yan,Lang, Jian-Ping
-
supporting information
p. 237 - 241
(2019/01/10)
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- Facile synthesis of 2-benzoxazoles via CuI/2,2'-bipyridine catalyzed intramolecular C–O coupling of 2-haloanilides
-
Development of newer methods for the synthesis of Benzoxazoles has of greater interest due to their wide range of biological activities and pharmaceutical importance. We herein report a facile and general method for the synthesis of 2-substituted Benzoxazoles via copper catalyzed intramolecular C–O cross-coupling of 2-haloanilides. A combination of CuI (5 mol%), 2,2'-bipyridine (10 mol%), Cs2CO3 (2 equiv.) in DMF solvent with 4 ? molecular sieves at 140 °C, illustrated the scope for tuning the reactivity of 2-haloanilides toward the selective formation of a series of 2-alkyl benzoxazole derivatives in moderate to good yields. This is the first systematic study using CuI/2,2'-Bipyridine as the catalytic system for the synthesis of 2-substituted Benzoxazoles. The outcome of the reaction was found to be significantly influenced by the aromatic and amide substituents of 2-haloanilides.
- Venu Saranya, Thachora,Rajan Sruthi, Pambingal,Anas, Saithalavi
-
supporting information
p. 297 - 307
(2019/01/18)
-
- Iridium-catalyzed intramolecular C–N and C–O/S cross-coupling reactions: Preparation of benzoazole derivatives
-
The irdium-catalyzed intramolecular arylcarbon-hetero cross-coupling reactions with o-haloarylamides or o-haloarylamidine have been effectively achieved using KOAc and just 1 mol% catalyst. The [Ir(cod)Cl]2 was proved to be more potential for smoothly assembling functional structures benzimidazoles, benzoxazoles and benzothiazoles, which was superior to Cu- and Pd-catalyzed systems. Simultaneously, a concise and efficient synthesis of tafamidis was developed in 5-g scale.
- Shi, Yajie,Zhou, Qifan,Du, Fangyu,Fu, Yang,Du, Yang,Fang, Ting,Chen, Guoliang
-
supporting information
(2019/09/10)
-
- Method for preparing derivatives of benzamide under microwave condition in aqueous phase
-
The invention discloses a method for preparing derivatives of benzamide under a microwave condition in an aqueous phase. A coupling reaction is carried out between substituted benzoic acid and amine under the microwave condition in the aqueous phase. The method for preparing the derivatives of benzamide is environmentally friendly, easy and convenient to operate, safe, low in cost and efficient. Compared with the prior art, the method can be applicable to a large number of functional groups, is high in yield, produces fewer by-products, and further is easy to operate, safe, low in cost and environmentally friendly. A formula is shown in the description.
- -
-
Paragraph 0019; 0064
(2019/03/28)
-
- Method for synthesizing amide compound through photocatalysis in water phase
-
The invention discloses a method for synthesizing an amide compound through photocatalysis in a water phase. The method comprises the following steps: putting catalysis amounts of a free radical initiator, an amine derivative, a carboxylic acid derivative, a phase transfer catalyst, an inorganic base and water into a reaction container, carrying out a reaction in a photocatalysis reaction instrument at certain power under a room temperature condition, after a certain time, carrying out extraction by using a small amount of ethyl acetate, and carrying out recrystallization, so as to obtain theamide compound, wherein the free radical initiator is eosin, methyl orange, sodium persulfate, ammonium persulfate or potassium peroxodisulfate, the phase transfer catalyst is tetrabutylammonium bromide, and the power of the photocatalytic reaction instrument is 5W. By adopting the method disclosed by the invention, toxic thionyl chloride or phosphorus oxychloride is not needed for a chlorinationreaction, water is adopted as a solvent, a novel photocatalysis method is used, and the amide compound with a high yield can be prepared through a room-temperature reaction for 2-5 hours with an incandescent light bulb of 5W, and in addition, the method is simple in aftertreatment, and low in cost and is an ideal green synthesis method of amide compounds.
- -
-
Paragraph 0061-0063
(2019/10/01)
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- An unsymmetrical covalent organic polymer for catalytic amide synthesis
-
Herein, we present the first report on the Covalent Organic Polymer (COP) directed non-classical synthesis of an amide bond. An economical route has been chosen for the synthesis of APC-COP using p-aminophenol and cyanuric chloride. APC-COP acts as a smart, valuable and sustainable catalyst for efficient access to the amide bond under mild conditions at room temperature in 30 min. APC-COP exhibits selectivity towards carboxylic acids over esters. The key features of this protocol involve the variety of parameters, viz. wider substrate scope, no use of additive and recyclability, which makes this approach highly desirable in gramscale synthesis. Moreover, we have shown the practical utility of the present method in the catalytic synthesis of paracetamol.
- Yadav, Deepika,Awasthi, Satish Kumar
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p. 179 - 186
(2019/12/28)
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- Cesium Fluoride and Copper-Catalyzed One-Pot Synthesis of Benzoxazoles via a Site-Selective Amide C?N Bond Cleavage
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We report herein a two-step one-pot strategy for the synthesis of benzoxazoles from amides by using cesium fluoride/copper as catalysts. This approach involves the in situ generation of acyl fluorides from the corresponding amides, and the acyl fluorides undergo transamidation and cyclization to give benzoxazoles in good yields. In this work, the amide C?N bonds are activated by CsF to form the acyl fluoride intermediates, which further react with o-bromoanilines to efficiently yield benzoxazoles. Notably, this methodology demonstrates a broad substrate scope, as primary/secondary benzamides are well tolerated, and this process might facilitate the development of one-pot transformations of amides. (Figure presented.).
- Luo, Zhongfeng,Wu, Hongxiang,Li, Yue,Chen, Yuwen,Nie, Jingyi,Lu, Siqi,Zhu, Yulin,Zeng, Zhuo
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p. 4117 - 4125
(2019/08/01)
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- Solvent- and transition metal-free amide synthesis from phenyl esters and aryl amines
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A general, economical, and environmentally friendly method of amide synthesis from phenyl esters and aryl amines was developed. This new method has significant advantages compared to previously reported palladium-catalyzed approaches. The reaction is performed transition metal- and solvent-free, using a cheap and environmentally benign base, NaH. This approach enabled us to obtain target amides in high yields with high atom economy.
- Rzhevskiy, Sergey A.,Ageshina, Alexandra A.,Chesnokov, Gleb A.,Gribanov, Pavel S.,Topchiy, Maxim A.,Nechaev, Mikhail S.,Asachenko, Andrey F.
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p. 1536 - 1540
(2019/01/24)
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- Synthesis of benzoxazoles via an iron-catalyzed domino C-N/C-O cross-coupling reaction
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An eco-friendly and efficient method has been developed for the synthesis of 2-arylbenzoxazoles via a domino iron-catalyzed C-N/C-O cross-coupling reaction. Some of the issues typically encountered during the synthesis of 2-arylbenzoxazoles in the presence of palladium and copper catalysts, including poor substrate scope and long reaction times have been addressed using this newly developed iron-catalyzed method.
- Yang, Bo,Hu, Weiye,Zhang, Songlin
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p. 2267 - 2270
(2018/02/06)
-
- Unexpected Rearrangement of 2-Bromoaniline under Biphasic Alkylation Conditions
-
Alkylation of 2-bromoaniline with benzyl bromide under ostensibly basic N-alkylation conditions resulted in migration of bromine from the 2- to the 4-aryl position. Herein we report our studies to elucidate the mechanism of this rearrangement with the objective of suppressing this unexpected outcome. We find that careful choice of reagents is critical, and that this behavior may be extrapolated to alkylation reactions of electron-rich bromo- and iodoanilines in general.
- Barraza, Scott J.,Denmark, Scott E.
-
supporting information
p. 2891 - 2895
(2017/10/06)
-
- Visible-Light-Mediated Synthesis of Amides from Aldehydes and Amines via in Situ Acid Chloride Formation
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An efficient visible-light photocatalysis-based one-pot amide synthesis method was developed; visible-light irradiation of a mixture of an aldehyde, tert-butyl hydrogen peroxide, and N-chlorosuccinimide using a Ru(bpy)3Cl2 photocatalyst afforded an acid chloride, which subsequently reacted with amine to yield the corresponding amide. The reaction was used to synthesize moclobemide and a D3 receptor intermediate.
- Iqbal, Naeem,Cho, Eun Jin
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p. 1905 - 1911
(2016/03/15)
-
- A comparative study of the catalytic activity of Co- and CoFe2O4-NPs in C-N and C-O bond formation: synthesis of benzimidazoles and benzoxazoles from o-haloanilides
-
Nanoparticles of cobalt ferrite (CoFe2O4-NPs) and pure cobalt (Co-NPs) were synthesized, and after characterization, their catalytic activities for dehalogenative intramolecular C-O and C-N bond formation reactions were investigated and compared. These inexpensive and efficient catalysts enabled creation of new methods for the synthesis of benzimidazoles and benzoxazoles in green media, with ligand-free and mild reaction conditions. All the reactions resulted in moderate to excellent yields under the optimized reaction conditions; however, the reactions using Co-NPs as the catalyst were completed in relatively shorter reaction times. Furthermore, analysis showed that the reusability of the two catalytic systems is approximately comparable.
- Hajipour, Abdol R.,Khorsandi, Zahra
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p. 10474 - 10481
(2016/12/07)
-
- Acidylation method of amine
-
The invention discloses an acidylation method of amine.The method includes the following steps that amine derivatives, hydrazide derivatives, organic peroxide and a catalyst are dissolved in a solvent and react at the temperature of 40-80 DEG C, and amide derivatives are obtained.The amide derivatives and hydrazide derivatives serve as initiators, the raw materials are easy to obtain and the number of varieties is large.Products obtained through the method are diverse in type, can be directly used and can also be used for other further reactions.The method is mild in reaction condition, simple in reaction operation and post-processing process, high in product yield and suitable for scale production.
- -
-
Paragraph 0023
(2016/10/10)
-
- Ligand-promoted, copper nanoparticles catalyzed one-pot synthesis of substituted benzoxazoles from 2-bromoanilines and acyl chlorides
-
A facile, highly efficient, and practical one-pot synthetic strategy for benzoxazoles was developed by using copper nanoparticles as a catalyst with o-bromoanilines and acyl chlorides as starting materials. With the promotion of 1,10-phenanthroline ligand, the copper nanoparticles catalyst showed highly catalytic activity under mild conditions. This methodology is tolerant of a wide variety of functional groups and gives good to excellent yields in most examples. Furthermore, the solid catalyst could be recovered and reused conveniently several times with satisfactory yields.
- Wang, Yong,Wu, Chaolong,Nie, Shoujie,Xu, Dingjian,Yu, Min,Yao, Xiaoquan
-
supporting information
p. 6827 - 6832
(2015/11/27)
-
- TRIFLUOROMETHYL GROUP-CONTAINING OXAZINE AND METHOD OF PRODUCING THE SAME
-
PROBLEM TO BE SOLVED: To provide a trifluoromethyl group-containing oxazine useful as a synthetic intermediate in medical and agricultural chemical and electronic material fields, and to provide a production method suitable for industrial production. SOLU
- -
-
Paragraph 0043-0045
(2017/03/17)
-
- One-pot synthesis of 3,4,5-trisubstituted 1,2,4-triazoles via the addition of hydrazides to activated secondary amides
-
A general approach has been developed for the one-pot synthesis of 3,4,5-trisubstituted 1,2,4-triazoles from secondary amides and hydrazides via triflic anhydride activation followed by microwave-induced cyclodehydration. In addition, the 1,2,4-triazole moiety is shown to be a useful directing group for Ru-catalyzed C-H arylation. Access to 1,2,4-triazolophenanthridine can be achieved from the reaction products using a Pd-catalyzed intramolecular C-H functionalization reaction.
- Bechara, William S.,Khazhieva, Inna S.,Rodriguez, Elsa,Charette, André B.
-
supporting information
p. 1184 - 1187
(2015/03/14)
-
- An efficient magnetic copper ferrite nanoparticle catalysed ligand and solvent free synthesis of N-aryl amide from aldoximes and iodobenzene
-
A simple, efficient, and environmentally benign method has been reported for the synthesis of N-aryl amides using aldoximes and iodobenzene under ligand free and solvent free conditions and using magnetically separable copper ferrite nanoparticles as catalyst. The catalyst was characterised using XRD, FEG-SEM, EDAX, ICP-AES and TEM and tested for recyclability for up to five cycles.
- Sarode, Sachin A.,Bhojane, Jeevan M.,Nagarkar, Jayashree M.
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p. 105353 - 105358
(2015/12/30)
-
- Copper-Catalyzed N-Benzoylation of Amines via Aerobic C-C Bond Cleavage
-
A general copper/air catalytic system for selectively oxidative C-C bond cleavage of 1,2-diarylethan-1-one has been developed, giving aromatic aldehydes and N-benzoylation products of various amines in moderate to excellent yields. This research provides an alternative approach for the N-benzoylation of amine in mild and neutral conditions.
- Fan, Wenyou,Yang, Youqing,Lei, Jianhua,Jiang, Qijian,Zhou, Wang
-
p. 8782 - 8789
(2015/09/15)
-
- Efficient synthesis of amides and esters from alcohols under aerobic ambient conditions catalyzed by a Au/mesoporous Al2O3 nanocatalyst
-
An efficient heterogeneous Au/mesoporous alumina nanocatalyst has been successfully developed for the synthesis of amides and esters from simple building blocks of readily available alcohols and amines. The processes were simple and were performed at room temperature and atmospheric pressure of O2 to form the desired products with up to 97% isolated yield. The ability of Au/mesoporous alumina to catalyze these reactions under ambient conditions further enhances the sustainability of these chemical processes. Furthermore, the nanocatalyst was stable to air and water and could be recovered and reused easily. The enhanced catalytic activity of Au/mesoporous alumina might be attributed to the presence of negatively charged Au nanoparticles that could promote oxidation processes as well as the stability of the mesoporous alumina support calcined at a high temperature of 800°C. Gold for green: Gold nanoparticles supported on mesoporous alumina catalyze the efficient synthesis of amides and esters from simple building blocks of readily available alcohols and amines under ambient aerobic reaction conditions (R1=aryl, alkyl, and R2=H, alkyl).
- Chng, Leng Leng,Yang, Jinhua,Ying, Jackie Y.
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p. 1916 - 1925
(2015/06/16)
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- Copper catalysed C-N bond formation via a sequential acylation and deacylation process: A novel strategy for the synthesis of benzanilides
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An efficient and mild oxidative amidation of aldehydes by means of acetanilides as amine components has been developed for the first time using copper catalysis. The approach is versatile and proceeds through sequential acylation and deacylation steps to afford benzanilides.
- Kumar, Saurabh,Vanjari, Rajeshwer,Guntreddi, Tirumaleswararao,Singh, Krishna Nand
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p. 9920 - 9924
(2015/02/19)
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- Palladium-catalyzed carbonylative synthesis of benzoxazinones from N -(o -bromoaryl)amides using paraformaldehyde as the carbonyl source
-
Carbonylation reactions have been widely used in organic synthesis. However, the manipulation of toxic and pressurized carbon monoxide limited their applications in organic laboratories. The search for alternative carbonyl sources as an important method for carbonylative organic synthesis is spreading. Herein, a series of substituted benzoxazinones were synthesized from N-(o-bromoaryl)amides by palladium-catalyzed carbonylation with paraformaldehyde as the carbonyl source, which is inexpensive, stable, and easy to use. Notably, this is the first example of using paraformaldehyde as the CO source in palladium-catalyzed carbonylative synthesis of heterocycles.
- Li, Wanfang,Wu, Xiao-Feng
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p. 10410 - 10416
(2015/02/19)
-
- Molybdenum-mediated desulfurization of dhiols and disulfides
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We have successfully achieved the molybdenum hexacarbonyl [Mo(CO) 6] mediated desulfurization of thiols and disulfides. In this reaction, the sulfhydryl (SH) mercapto groups of aryl, benzyl, primary and secondary alkyl thiols, and S-S single bonds of disulfides can be removed. This reaction has high functional group tolerance and is not affected by steric hindrance. The results of the reactions in acetone-d 6 suggest that the sources of hydrogen in the thiol and disulfide desulfurizations are the hydrogen atom(s) of a sulfhydryl group and acetone (solvent), respectively, and that the desulfurization proceeds via the formation of an organomolybdenum species. Georg Thieme Verlag Stuttgart. New York.
- Wang, Zhen,Kuninobu, Yoichiro,Kanai, Motomu
-
supporting information
p. 1869 - 1872
(2014/08/18)
-
- Facile access to amides and hydroxamic acids directly from nitroarenes
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A new method for synthesis of amides and hydroxamic acids from nitroarenes and aldehydes is described. The MnO2 catalyzed thermal deoxygenation of nitrobenzene resulted in formation of a reactive nitroso intermediate which on reaction with aldehydes provided amides and hydroxamic acids. The thermal neat reaction in the presence of 0.01 mmol KOH predominantly led to formation of hydroxamic acid whereas reaction in the presence of 1 mmol acetic acid produced amides as the only product. the Partner Organisations 2014.
- Jain, Shreyans K.,Aravinda Kumar,Bharate, Sandip B.,Vishwakarma, Ram A.
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p. 6465 - 6469
(2014/08/18)
-
- Synthesis of 6-substituted 2-pyrrolyl and indolyl benzoxazoles by intramolecular O-arylation in photostimulated reactions
-
The synthesis of a series of 6-substituted 2-pyrrolyl and 2-indolyl benzoxazoles by photostimulated C-O cyclization of anions from 2-pyrrole carboxamides, 2-indole carboxamides, or 3-indole carboxamides has been found to proceed in good to excellent yields (41-100%) in DMSO and liquid ammonia. The pyrrole and indole carboxamides are obtained in good to very good isolated yields by an amidation reaction of different 2-haloanilines with 2-carboxylic acid of pyrrole and 2- or 3-carboxylic acid of indole. To explain the regiochemical outcome of these reactions (C-O arylation vs C-N or C-C arylation), a theoretical analysis was performed using DFT methods and the B3LYP functional.
- Vaillard, Victoria A.,Guastavino, Javier F.,Buden, Maria E.,Bardagi, Javier I.,Barolo, Silvia M.,Rossi, Roberto A.
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experimental part
p. 1507 - 1519
(2012/03/11)
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- Efficient amide formation from arylamines and esters promoted by AlCl 3/Et3N: An experimental and computational investigation
-
Efficient and selective preparation of amides from arylamines and esters has been achieved with an AlCl3/Et3N pair under mild conditions. A large number of arylamines were successfully acylated to the corresponding amides in high yields and short reaction times. For instance, a 94% yield of p-bromoacetanilide was obtained from p-bromoaniline and ethyl acetate in 10 min at room temperature. In addition, a computational study on the N-acylation of amines was performed using density functional theory. It was found that the energy barrier for N-acylation of aniline is 10 kcal/mol higher than that of methylamine. In the presence of AlCl3, the activation energy for the N-acylation of aniline was reduced by 27.7 kcal/mol with the endothermic process becoming exothermic. Springer Science+Business Media B.V. 2012.
- Tong, Xinli,Ren, Zhangshun,Que, Xiaolong,Yang, Qiwu,Zhang, Wenqin
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p. 1961 - 1968
(2013/02/22)
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- Pd(OAc)2-catalyzed carbonylative coupling of aryl iodide with ortho-haloamines in water
-
The carbonylative cross coupling of aryl iodide with ortho-haloaniline to ortho-haloanilide using phosphine-free Pd(OAc)2 catalyst in water as a reaction medium has been studied. The present protocol facilitated the reaction of o-haloanilines with a wide variety of hindered and functionalized aryl iodides, affording good yields of the desired products. The protocol was also extended for the synthesis of benzoxazoles through cyclization of ortho-haloanilide using Cu(acac)2 catalyst. Taylor & Francis Group, LLC.
- Tambade, Pawan J.,Patil, Yogesh P.,Qureshi, Ziyauddin S.,Dhake, Kishor P.,Bhanage, Bhalchandra M.
-
supporting information; experimental part
p. 176 - 185
(2011/10/31)
-
- A convenient and general palladium-catalyzed carbonylative coupling for the synthesis of 2-arylbenzoxazinones
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CO and CO again: A new double carbonylation methodology for the synthesis of 2-arylbenzoxazinones has been developed (see scheme). Copyright
- Wu, Xiao-Feng,Schranck, Johannes,Neumann, Helfried,Beller, Matthias
-
supporting information; scheme or table
p. 12246 - 12249
(2011/12/02)
-
- Desulfurization of Thioamides into Amides with H2O 2/ZrCl4 Reagent System
-
The hydrogen peroxide/zirconium(IV) chloride reagent system has been used as a new and efficient reagent for the deprotection/desulfurization of thioamides to amides. This system is reasonably general and can be applied to the conversion of several thioamides to the corresponding amides. The salient features of this protocol are short reaction times, good chemoselectivity, cleaner reaction profiles, and simple workup that precludes the use of toxic solvents. Georg Thieme Verlag Stuttgart.
- Bahrami, Kiumars,Khodaei, Mohammad Mehdi,Tirandaz, Yeganeh
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experimental part
p. 369 - 371
(2009/07/04)
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- H2O2/SOCl2: a useful reagent system for the conversion of thiocarbonyls to carbonyl compounds
-
The H2O2/SOCl2 reagent system has been used as a new and efficient reagent for deprotection of thiocarbonyls to carbonyl compounds. The salient features of this protocol are short reaction times, good chemoselectivity, clean reaction profiles, and simple work-up that preclude the use of toxic solvents.
- Bahrami, Kiumars,Khodaei, Mohammad M.,Farrokhi, Azita
-
supporting information; experimental part
p. 7658 - 7661
(2009/12/04)
-
- Conversion of thiobenzamides to benzothiazoles via intramolecular cyclization of the aryl radical cation
-
A new and general method has been developed for the intramolecular cyclization of thiobenzamides to benzothiazoles via aryl radical cations as reactive intermediates. The method utilizes phenyliodine(III) bis(trifluoroacetate) (PIFA) in trifluoroethanol or cerium ammonium nitrate (CAN) in aqueous acetonitrile at room temperature to effect cyclization within 30 min in moderate yields.
- Downer-Riley, Nadale K.,Jackson, Yvette A.
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p. 7741 - 7744
(2008/12/20)
-
- Copper-catalyzed domino annulation approaches to the synthesis of benzoxazoles under microwave-accelerated and conventional thermal conditions
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(Chemical Equation Presented) Two domino annulation approaches for benzoxazole synthesis have been developed. In the first approach, copper-catalyzed intermolecular cross-coupling of 1,2-dihaloarenes with primary amides initially forms the Ar-N bond of the benzoxazole ring, followed by copper-catalyzed intramolecular cyclization to form the Ar-O bond. Benzoxazoles were formed in good yields for the reaction of 1,2-dibromobenzene, but the reaction was not regioselective for the reaction of 3,4-dibromotoluene. Furthermore, the method is limited by the availability of 1,2-dihaloarenes. As a result of these limitations, an alternative more versatile one-pot domino annulation strategy was developed involving reaction of 2-bromoanilines with acyl chlorides in the presence of Cs2CO3, catalytic CuI, and the non-acylatable ligand 1,10-phenanthroline. Under these conditions initial acylation of the aniline is followed by copper-catalyzed intramolecular cyclization of the resultant 2-haloanilide to form the Ar-O bond of the benzoxazole ring. Optimized conditions using microwave irradiation achieved much shorter reaction times than conventional heating (i.e., 210 °C for 15 min versus 95 °C for 24 h) and were applied to the synthesis of a small library of benzoxazoles. These copper-catalyzed approaches complement existing strategies for benzoxazole synthesis, which typically utilize 2-aminopheonls as precursors.
- Viirre, Russell D.,Evindar, Ghotas,Batey, Robert A.
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p. 3452 - 3459
(2008/09/20)
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- Copper-catalysed intramolecular O-arylation of aryl chlorides and bromides: a straightforward approach to benzo[d]oxazoles in water
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A general, efficient and more sustainable protocol for the copper-catalysed intramolecular O-arylation of o′-haloanilides leading to the benzo[d]oxazole core is reported. Remarkably, the optimised conditions allowed for the use of inexpensive and easily available aryl chlorides as arylating agents. Moreover, all reactions were carried out employing exclusively water as the solvent, rendering the methodology presented herein highly valuable from both environmental and economic points of view.
- Barbero, Nekane,Carril, Mónica,SanMartin, Raul,Domínguez, Esther
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p. 10425 - 10432
(2008/02/12)
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- Parallel synthesis of a library of benzoxazoles and benzothiazoles using ligand-accelerated copper-catalyzed cyclizations of ortho-halobenzanilides
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A general method for the formation of benzoxazoles via a copper-catalyzed cyclization of ortho-haloanilides is reported. This approach complements the more commonly used strategies for benzoxazole formation which require 2-aminophenols as substrates. The reaction involves an intramolecular C-O cross-coupling of the ortho-haloanilides and is believed to proceed via an oxidative insertion/reductive elimination pathway through a Cu(I)/Cu(III) manifold. The reaction is also applicable to the formation of benzothiazoles. A variety of ligands including 1,10-phenanthroline and N,N′- dimethylethylenediamine were shown to provide ligand acceleration/stabilization in the reaction. Optimal conditions for cyclization used a catalyst combination of CuI and 1,10-phenanthroline (10 mol %). The method was amenable to a parallel-synthesis approach, as demonstrated by the synthesis of a library of benzoxazoles and benzothiazoles substituted at various positions in the ring. Most examples utilized the cyclization of ortho-bromoanilides, but orthoiodoanilides and ortho-chloroanilides also undergo a reaction under these conditions. The rate of reaction of the ortho-haloanilides follows the order I > Br > Cl, consistent with oxidative addition being the rate-determining step.
- Evindar, Ghotas,Batey, Robert A.
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p. 1802 - 1808
(2007/10/03)
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- Synthesis of 2-substituted-benzothiazoles by palladium-catalyzed intramolecular cyclization of o-bromophenylthioureas and o-bromophenylthioamides
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2-Amino-, and 2-alkyl-benzothiazoles have been efficiently prepared by palladium catalyzed cyclization of o-bromophenylthioureas and o-bromophenylthiamides. Results were best with the Pd2(dba)3/monophosphine catalytic system.
- Benedí, Carolina,Bravo, Fernando,Uriz, Pedro,Fernández, Elena,Claver, Carmen,Castillón, Sergio
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p. 6073 - 6077
(2007/10/03)
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- Dication C(R1)-N(R2)2 synthons and their use in the synthesis of formamidines, amidines, and α-aminonitriles
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A combination of amides and 2-pyridinesulfonyl chloride was evaluated as synthons of the dication C(R1)-N(R2)2/2+. When the substrates were primary amines, high yields of formamidines and amidines were obtained. When the substrates were α-aminoamides, α-aminonitriles were obtained. Through this process, naturally occurring α-aminoacids can be transformed into chiral α-aminonitriles with complete retention of stereochemical configuration. All reactions proceed rapidly at room temperature, and normally finish within 10 min, with yields ranging from 80 to 95% for most cases. Among the sulfonyl chlorides examined, 2-pyridinesulfonyl chloride stands out in both reaction rate and selectivity of formamidine or amidine versus sulfonyl amide. The scope and limitations of the reaction among different types of amides as synthons and amines as substrates were examined. (C) 2000 Elsevier Science Ltd.
- Cai, Lisheng,Han, Ying,Ren, Sumei,Huang, Liangfu
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p. 8253 - 8262
(2007/10/03)
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- Selectivities in Reactions of Organolithium Reagents with Aryl Bromides Which Bear Proton-Donating Groups
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Studies of substrates which offer an acidic hydrogen and an aryl bromide for reaction with an organolithium reagent have been carried out with a series of benzene bromo amides and bromo anilides as well as selected benzene bromo carboxylic acids, bromoanilines, and bromobenzylamines.A representative example is the reaction of N-ethyl-N-deutero-o-bromobenzamide (6-d) with 1-lithio-3-phenylpropane to give N-ethyl-o-deuterobenzamide (46percent, 94percent-d) (7-d), N-ethyl-o-bromobenzamide (6) (49percent), 3-deutero-1-phenylpropane (51percent, 92percent-d), and 1-bromo-3-phenylpropane (48percent).Product formation in this and related cases is explained by the operation of a two step sequence in which an initial deprotonation is followed by a bromine-lithium exchange which is accelerated with respect to mixing.Such a sequence is consistent with the results of deuterium labeling and with changes in product ratios on different mixing and with differently aggregated organolithium reagents.Support is provided for the operation of two pathways for the expedited bromine-lithium exchange reactions.In one pathway a high local concentration of the organolithium reagent promotes rapid reaction and in the second the exchange reaction occurs within an initially formed complex.The selectivity for removal of a bromine ortho to a lithiated carboxamide is found to be 5-8 with n-butyllithium, and satisfactory synthetic ortho selectivity is obtained for N-ethyl-2,5-dibromobenzamide with phenyllithium.
- Beak, Peter,Musick, Timothy J.,Liu, Chao,Cooper, Thomas,Gallagher, Donald J.
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p. 7330 - 7335
(2007/10/02)
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- Oxidation during reductive cyclisations using Bu3SnH
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Reductive cyclisations using Bu3SnH include an "oxidation" step if the removal of an acidic proton from the intermediate cyclised radical, by Bu3SnH acting as a base, is favourable. A "pseudo" SRN1 mechanism is proposed.
- Bowman, W. Russell,Heaney, Harry,Jordan, Benjamin M.
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p. 10119 - 10128
(2007/10/02)
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