- Iron-catalyzed cross-coupling of N?methoxy amides and arylboronic acids for the synthesis of N-aryl amides
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An efficient iron-catalyzed synthesis of N-aryl amides from N?methoxy amides and arylboronic acids is developed. FeCl3 is used as the sole catalyst for the cross-coupling reaction between N?methoxy amides and arylboronic acids without any other
- Li, Jinhui,Liu, Jin-Biao,Luo, Nianhua,Qiu, Guanyinsheng,Ren, Shangfeng,Wang, Ying,Xie, Huilin
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- α-Imino Iridium Carbenes from Imidoyl Sulfoxonium Ylides: Application in the One-Step Synthesis of Indoles
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Imidoyl sulfoxonium ylides are presented for the first time as potential precursors to generate α-imino metal-carbene intermediates and applied in direct C-H functionalization reactions catalyzed by [Ir(cod)Cl]2 (4 mol %) to provide 2-substituted indoles (up to 70% yield) in just one step. This class of sulfur ylide is successfully obtained from imidoyl chloride and dimethylsulfoxonium methylide (23 new examples in 45-85% yield) or by imino group formation from the corresponding β-keto sulfoxonium ylides and anilines in the presence of TiCl4 as a Lewis acid (9 examples in 33-94% yield).
- Burtoloso, Antonio C. B.,Caiuby, Clarice A. D.,De Jesus, Matheus P.
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p. 7433 - 7445
(2020/06/27)
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- Switching from biaryl formation to amidation with convoluted polymeric nickel catalysis
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A stable, reusable, and insoluble poly(4-vinyl-pyridine) nickel catalyst (P4VP-NiCl2) was prepared through the molecular convolution of poly(4-vinylpyridine) (P4VP) and nickel chloride. We proposed a coordination structure of the Ni center in the precatalyst based on elemental analysis and Ni K-edge XANES, and we confirmed that it is consistent with Ni K-edge EXAFS. The Suzuki?Miyaura-type coupling of aryl halides and arylboronic esters proceeded using P4VP-NiCl2 (0.1 mol % Ni) to give the corresponding biaryl compounds in up to 94% yield. Surprisingly, when the same reaction of aryl halides and arylboronic acid/ester was carried out in the presence of amides, the amidation proceeded predominantly to give the corresponding arylamides in up to 99% yield. In contrast, the reaction of aryl halides and amides in the absence of arylboronic acid/ester did not proceed. P4VP-NiCl2 successfully catalyzed the lactamization for preparing phenanthridinone. P4VP-NiCl2 was reused five times without significant loss of catalytic activity. Pharmaceuticals, natural products, and biologically active compounds were synthesized efficiently using P4VPNiCl2 catalysis. Nickel contamination in the prepared pharmaceutical compounds was not detected by ICP-MS analysis. The reaction was scaled to multigrams without any loss of chemical yield. Mechanistic studies for both Suzuki?Miyaura and amidation were performed.
- Sen, Abhijit,Dhital, Raghu N.,Sato, Takuma,Ohno, Aya,Yamada, Yoichi M.A.
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p. 14410 - 14418
(2020/12/21)
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- Highly Chemoselective, Transition-Metal-Free Transamidation of Unactivated Amides and Direct Amidation of Alkyl Esters by N-C/O-C Cleavage
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The amide bond is one of the most fundamental functional groups in chemistry and biology and plays a central role in numerous processes harnessed to streamline the synthesis of key pharmaceutical and industrial molecules. Although the synthesis of amides is one of the most frequently performed reactions by academic and industrial scientists, the direct transamidation of tertiary amides is challenging due to unfavorable kinetic and thermodynamic contributions of the process. Herein, we report the first general, mild, and highly chemoselective method for transamidation of unactivated tertiary amides by a direct acyl N-C bond cleavage with non-nucleophilic amines. This operationally simple method is performed in the absence of transition metals and operates under unusually mild reaction conditions. In this context, we further describe the direct amidation of abundant alkyl esters to afford amide bonds with exquisite selectivity by acyl C-O bond cleavage. The utility of this process is showcased by a broad scope of the method, including various sensitive functional groups, late-stage modification, and the synthesis of drug molecules (>80 examples). Remarkable selectivity toward different functional groups and within different amide and ester electrophiles that is not feasible using existing methods was observed. Extensive experimental and computational studies were conducted to provide insight into the mechanism and the origins of high selectivity. We further present a series of guidelines to predict the reactivity of amides and esters in the synthesis of valuable amide bonds by this user-friendly process. In light of the importance of the amide bond in organic synthesis and major practical advantages of this method, the study opens up new opportunities in the synthesis of pivotal amide bonds in a broad range of chemical contexts.
- Li, Guangchen,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
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supporting information
p. 11161 - 11172
(2019/08/07)
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- The use of Cr (CO)6 as an alternative CO source in Pd-catalyzed C-N bond formation: Synthesis of benzamides
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An efficient strategy for the synthesis of benzamides from acetamides and aryl iodides using 1?mol% Pd (OAc)2 as catalyst and Cr (CO)6 as CO-precursor is described. This new synthetic methodology displays high functional group tolerance on both substrates and avoids the need for ligands, reducing agents, or other additives. The corresponding products were obtained in good to excellent yields at atmospheric pressure under mild reaction conditions.
- Mozaffari, Mozhdeh,Nowrouzi, Najmeh,Abbasi, Mohammad
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- 1,3-Oxazolidin-5-ones derived from proline as chiral components in the synthesis of predictive enantioselective coupling reagents
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1,3-Oxazolidin-5-ones derived from both enantiomers of proline and trichloroacetaldehyde were prepared and applied as an amine component in the synthesis of chiral predictive triazine-based coupling reagents. The reagents were found to be useful in condensations yielding enantiomerically enriched products from racemic substrates.
- KAsperowicz-Frankowska, Katarzyna,Kolesińska, Beata,Gzik, Anna,Jastrzabek, Konrad,Kamiński, Zbigniew J.
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p. 921 - 927
(2018/09/22)
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- 4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium Toluene-4-sulfonate (DMT/NMM/TsO?) Universal Coupling Reagent for Synthesis in Solution
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4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium toluene-4-sulfonate (DMT/NMM/TsO?), a representative member of the inexpensive and environmentally-friendly N-triazinylammonium family of sulfonates, has been found to be a very effective coupling reagent for the synthesis of amides, esters and peptides in solution. This study confirms the usefulness of DMT/NMM/TsO? for peptide synthesis in solution, starting from Z-, Fmoc-, and Boc-protected substrates as well as unnatural building blocks. Peptide synthesis with DMT/NMM/TsO? produced high yields, with high crude product purity and low risk of racemization. In all cases, stoichiometric amounts of reagents were used and the standard synthetic procedure, without the need for time-consuming optimization stages or expensive chromatographic purification. DMT/NMM/TsO? was also found to be very useful for the synthesis of oligopeptides using a fragment coupling strategy.
- Fraczyk, Justyna,Kaminski, Zbigniew J.,Katarzynska, Joanna,Kolesinska, Beata
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- Chemoselective Synthesis of N-arylbenzamides and Benzoyloxyacetanilides from Aryl Isocyanides: Styrene as Aryl and Arylcarboxymethylene Source
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Styrenes serve as unique aryl or arylcarboxymethylene source towards aryl isocyanides in the presence of Cu(II)/TBHP, and yield N-arylbenzamides or benzoyloxyacetanilides respectively. The chemoselectivity of the reaction is controlled by the nature of the substituents present on styrene ring. Whereas styrenes substituted with electron-releasing alkyl and alkoxy groups yield N-arylbenzamides, unsubstituted styrene and those with electron-withdrawing substituents furnish benzoyloxyacetanilides as the major product. With benzylamines as the substrate, N-arylbenzamides are formed exclusively as they act only as an aryl donor. TBHP serves as a promoter and oxygen source. Both the pathways are believed to proceed through an initial oxidative C?C bond cleavage of styrene. (Figure presented.).
- Sharma, Poonam,Jain, Nidhi
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supporting information
p. 1932 - 1937
(2018/03/27)
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- Copper-Catalyzed Coupling Reaction of (Hetero)Aryl Chlorides and Amides
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Cu2O/N,N′-bis(thiophen-2-ylmethyl)oxalamide is established to be an effective catalyst system for Goldberg amidation with inferior reactive (hetero)aryl chlorides, which have not been efficiently documented by Cu-catalysis to date. The reaction is well liberalized toward a variety of functionalized (hetero)aryl chlorides and a wide range of aromatic and aliphatic primary amides in good to excellent yields. Furthermore, the arylation of lactams and oxazolidinones is achieved. The present catalytic system also accomplished an intramolecular cross-coupling product.
- De, Subhadip,Yin, Junli,Ma, Dawei
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supporting information
p. 4864 - 4867
(2017/09/23)
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- Base-promoted synthesis of N-arylbenzamides by N-benzoylation of dimethylphenylthioureas
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An efficient synthesis of 10 N-arylbenzamides was achieved by N-benzoylation of N,N-dimethyl-(N'-phenyl)thioureas with 4-substituted benzoyl chlorides in dimethylacetamide in the presence of K2CO3. The features of this method include
- Liu, Xing,Xu, Wan,Zeng, Meng-Tian,Liu, Min,Chang, Cai-Zhu,Zhu, Hui,Dong, Zhi-Bing
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p. 484 - 486
(2017/08/18)
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- Catalyst-Free Singlet Oxygen-Promoted Decarboxylative Amidation of α-Keto Acids with Free Amines
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A novel catalyst-free decarboxylative amidation of α-keto acids with amines under mild conditions has been developed. Advantages of the new protocol include avoidance of metal catalysts and high levels of functional group tolerance. In addition, the reaction can be scaled up and shows high chemoselectivity. Preliminary mechanistic studies suggest that singlet oxygen, generated from oxygen under irradiation, is the key promoter for this catalyst-free transformation.
- Xu, Wen-Tao,Huang, Bei,Dai, Jian-Jun,Xu, Jun,Xu, Hua-Jian
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supporting information
p. 3114 - 3117
(2016/07/14)
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- Highly efficient microwave-assisted CO aminocarbonylation with a recyclable Pd(II)/TPP-β-cyclodextrin cross-linked catalyst
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The incorporation of the carbonyl moiety into organic molecules using a three-component matrix, including carbon monoxide, an organic halide, and a nucleophilic component, offers a simple and versatile approach to the formation of carboxylic acids, anhydrides, esters, amides, and ketones. The design of a sustainable synthetic protocol for aminocarbonylation can be efficiently accomplished using a multifaceted strategy that combines solid green catalysts and suitable enabling techniques. The safe and synergistic use of carbon monoxide in a microwave reactor under pressure may be able to create a technological breakthrough in aminocarbonylation reactions. Moreover, a new recyclable catalytic system "CβCAT" based on Pd(II)-triphenylphosphine embedded in cross-linked β-cyclodextrin (hexamethylene diisocyanate) has been found to be very efficient in aryl iodide aminocarbonylation reactions.
- Calcio Gaudino, Emanuela,Carnaroglio, Diego,Martina, Katia,Palmisano, Giovanni,Penoni, Andrea,Cravotto, Giancarlo
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supporting information
p. 499 - 505
(2015/04/27)
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- Synthesis of chiral triazine coupling reagents based on esters of n-alkylproline and their application in the enantioselective incorporation of d or l amino acid residue directly from racemic substrate
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Esters of N-methylproline and N-allylproline were prepared and used as component for synthesis of chiral triazine based coupling reagents. N-Triazinylammonium tetrafluoroborate obtained from methylester of L-N-methylproline, 2-chloro-4,6-dimethozxy-1,3,5-
- Kasperowicz-Frankowska, Katarzyna,Gzik, Anna,Dziemidkiewicz, Michal,Kolesi-Ska, Beata,Kamiski, Zbigniew J.
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p. 994 - 1003
(2015/02/02)
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- Visible-light-mediated decarboxylation/oxidative amidation of α-keto acids with amines under mild reaction conditions using O2
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Photochemistry has ushered in a new era in the development of chemistry, and photoredox catalysis has become a hot topic, especially over the last five years, with the combination of visible-light photoredox catalysis and radical reactions. A novel, simple, and efficient radical oxidative decarboxylative coupling with the assistant of the photocatalyst [Ru(phen)3]Cl 2 is described. Various functional groups are well-tolerated in this reaction and thus provides a new approach to developing advanced methods for aerobic oxidative decarboxylation. The preliminary mechanistic studies revealed that: 1)an SET process between [Ru(phen)3]2+* and aniline play an important role; 2)O2 activation might be the rate-determining step; and 3)the decarboxylation step is an irreversible and fast process. Bring to light: A new approach to oxidative decarboxylation under visible light using O2 as the oxidant has been developed. A variety of functional groups were well-tolerated in this reaction and insights into the mechanism were investigated with the assistance of EPR spectroscopy, cyclic voltammetry, and theoretical studies.
- Liu, Jie,Liu, Qiang,Yi, Hong,Qin, Chu,Bai, Ruopeng,Qi, Xiaotian,Lan, Yu,Lei, Aiwen
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supporting information
p. 502 - 506
(2014/01/23)
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- DDQ-promoted direct transformation of benzyl hydrocarbons to amides via tandem reaction of the CDC reaction and Beckmann rearrangement
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An atom-efficient and transition metal-free approach to amides from the corresponding benzyl hydrocarbons through C-H and C-C bond cleavage has been developed. Mechanistic studies have shown that a DDQ-promoted cross-dehydrogenative coupling (CDC) reaction with subsequent oxidation and rearrangement are involved in this transformation. The Royal Society of Chemistry.
- Qiu, Jun,Zhang, Ronghua
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supporting information
p. 6008 - 6012
(2013/09/12)
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- Facile preparation of amides from carboxylic acids and amines with ion-supported Ph3P
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Ion-supported Ph3P, 4-(diphenylphosphino)benzyltrimethylammonium bromide (IS-Ph3P), could be used for the facile amidation of a wide range of carboxylic acids with amines in the presence of bromotrichloromethane to provide the corresponding amides in good yields. In the present reaction, the desired amides were obtained in good yields with high purity by simple extraction of the reaction mixture with diethyl ether or chloroform and subsequent removal of the solvent from the extract. Moreover, ion-supported Ph3PO (IS-Ph3PO), which was a co-product derived from IS-Ph3P in the present reductive condensation, was recovered in high yield and could be reduced to IS-Ph3P for reuse in the same amidation of carboxylic acid.
- Kawagoe, Yuhsuke,Moriyama, Katsuhiko,Togo, Hideo
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p. 3971 - 3977
(2013/06/27)
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- P-Triazinylphosphonium chlorides as a new group of coupling reagents
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Tertiary phosphines in reaction with 2-chloro-4,6-dialkoxy-1,3,5-triazines gave unstable quaternary P-triazinylphosphonium chlorides, which readily decomposed with a departure of the alkyl group of the triazine ring substituent. Stable quaternary P-triazinylphosphonium chlorides were obtained only in reaction of 2-chloro-4,6-diphenoxy-1,3,5-triazine. Both, stable quaternary P-triazinylphosphonium chlorides as well unstable analogues prepared in situ activated carboxylic acid yielding "superactive" triazine esters, useful as highly efficient reagents in peptide bond synthesis.
- Kolesinska, Beata,Mrozek, Agnieszka,Fraczyk, Justyna,Kaminski, Zbigniew J.
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p. 569 - 583
(2013/08/24)
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- N-Triazinylammonium salts, a method of preparation and uses thereof
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The invention provides inner quaternary N-triazinyl- ammonium salts of sulphonic acids, of the Formula 1, a method of preparation thereof and a use thereof as condensation reagents in condensation reactions.
- -
-
Page/Page column 10
(2012/02/04)
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- The synthesis of N-arylated amides via copper(II) triflate-catalyzed direct oxygenation and N-arylation of benzylamines with aryl iodides
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An efficient approach for the synthesis of N-arylated amides by copper(II) triflate-catalyzed direct oxygenation and N-arylation reaction of benzylamines with aryl iodides is reported. Various benzylamines and aryl iodides can participate in the reaction, providing a series of N-arylated amides in moderate to good yields.
- Xu, Mei,Zhang, Xiao-Hong,Shao, Yin-Lin,Han, Jiang-Sheng,Zhong, Ping
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supporting information
p. 2665 - 2670,6
(2012/12/12)
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- The synthesis of N-arylated amides via copper(II) triflate-catalyzed direct oxygenation and N-arylation of benzylamines with aryl iodides
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An efficient approach for the synthesis of N-arylated amides by copper(II) triflate-catalyzed direct oxygenation and N-arylation reaction of benzylamines with aryl iodides is reported. Various benzylamines and aryl iodides can participate in the reaction, providing a series of N-arylated amides in moderate to good yields.
- Xu, Mei,Zhang, Xiao-Hong,Shao, Yin-Lin,Han, Jiang-Sheng,Zhong, Ping
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supporting information
p. 2665 - 2670
(2013/01/15)
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- Facile AlCl3-promoted catalytic beckmann rearrangement of ketoximes
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Aluminum chloride, an inexpensive and commercially available Lewis acid traditionally employed for Beckmann rearrangement with stoichiometric amounts, has been now found to smoothly promote the Beckmann rearrangement of various ketoximes to the corresponding amides (up to 99% of yield) with 10mol% catalyst loading in anhydrous acetonitrile under reflux temperature.
- Liu, Li-Feng,Liu, Hua,Pi, Hong-Jun,Yang, Shuo,Yao, Min,Du, Wenting,Deng, Wei-Ping
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experimental part
p. 553 - 560
(2011/04/22)
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- A mild and highly efficient catalyst for Beckmann rearrangement, BF 3·OEt2
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BF3·OEt2 (Boron trifluoride etherate), an inexpensive and commercially easily available Lewis acid stoichiometrically employed for Beckamann rearrangement in general, was now found to efficiently catalyze Beckmann rearrangement of ketoximes into their corresponding amides (up to 99% yield) in anhydrous acetonitrile under reflux temperature.
- An, Na,Pi, Hongjun,Liu, Lifeng,Du, Wenting,Deng, Weiping
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experimental part
p. 947 - 950
(2012/01/05)
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- Manganese-catalyzed cleavage of a carbon-carbon single bond between carbonyl carbon and α-carbon atoms of ketones
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Singled out: Treatment of ketones with carbodiimides in the presence of a catalytic amount of either [{HMn(CO)4}3] or [Mn 2(CO)10] gave amides in good to excellent yields. In this reaction, the carbon-carbon single bond of a ketone is cleaved efficiently. The reaction also proceeded by using isocyanates instead of carbodiimides. Copyright
- Kuninobu, Yoichiro,Uesugi, Tadamasa,Kawata, Atsushi,Takai, Kazuhiko
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p. 10406 - 10408
(2011/12/04)
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- Cyclopentadienyl-free rare-earth metal amides [{(CH2SiMe 2){(2,6iPr2C6H3)N} 2}Ln{N(SiMe3)2}(THF)] as highly efficient versatile catalysts for C-C and C-N bond formation
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Efficient methods have been developed for the direct synthesis of amides from aldehydes and a straightforward route to propiolamidines using cyclopentadienyl-free rare-earth metal amides [{(CH2SiMe 2){(2,6-iPr2C6H3)N} 2}Ln{N(SiMe3)2}(THF)] [Ln = Yb (1), Y (2), Dy (3), Sm (4), Nd (5)] as versatile catalysts, The results indicate that in the direct synthesis of amides from aldehydes the catalysts have the activity order 2>1~3~4~5. These methods have the advantage of easy preparation of the catalysts, low catalyst loading, high conversion of substrates to products, mild reaction conditions, and compatibility with a wide range of substrates.
- Wu, Yunjun,Wang, Shaowu,Zhang, Lijun,Yang, Gaosheng,Zhu, Xiancui,Zhou, Zhihong,Zhu, Hong,Wu, Shihong
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supporting information; experimental part
p. 326 - 332
(2010/04/06)
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- Samarium-mediated mild and facile method for the synthesis of amides
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Samarium-mediated facile method for the formation of amide bonds by the reaction of acyl chlorides and amines is described. The reaction afforded high yields of the desired amides under mild and neutral conditions.
- Shi, Feng,Li, Jian,Li, Chunju,Jia, Xueshun
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experimental part
p. 6049 - 6051
(2010/11/21)
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- Unexpected results from the re-investigation of the Beckmann rearrangement of ketoximes into amides by using TsCl
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TsCl (p-toluenesulfonyl chloride), a commercially available organosulfonyl chloride, has been widely used as a stoichiometric dehydrogenation reagent in the transformation of ketoximes into corresponding amides via the Beckmann rearrangement. It has been now found to catalyze the Beckmann rearrangement with high catalytic efficiency, converting a wide range of ketoximes into their corresponding amides under mild condition with good to excellent yields (up to 99% of yield with 1-5 mol % of catalyst loading).
- Pi, Hong-Jun,Dong, Jin-Dong,An, Na,Du, Wenting,Deng, Wei-Ping
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experimental part
p. 7790 - 7793
(2010/01/06)
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- Metal-free synthesis of alkynyl imines using an oxophosphonium-mediated approach at ambient temperatures
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A metal-free approach was developed for the mild synthesis of N-aryl α-alkynyl imines from corresponding amide precursors for the first time. The electronic effects of substrates and the reaction mechanisms were investigated and discussed. This newly deve
- Dong, Qing-Li,Liu, Guan-Sai,Zhou, Hai-Bin,Chen, Lin,Yao, Zhu-Jun
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p. 1636 - 1640
(2008/09/18)
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- Acyl Carbamoyl Selenides and Related Sulfur Isologues: Synthesis and X-Ray Structural Analyses
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Selenocarboxylic acids [RC(=O)SeH] were found to readily react with aryl, acyl, and arenesulfonyl isocyanates to give the corresponding acyl carbamoyl selenides 3 [RC(=O)SeC(=O)NHR', R'= aryl, C6H5CO, and 4-MeC6H4SO2] in good yields. Their tautomers [RC(=O)SeC(=NR')OH] were also detected by 1H, 13C, and 77Se NMR spectroscopies. The structure of 3 [R = 2,6-(MeO)2C6H3, R' = 4-MeC6H4] was characterized by X-ray crystallography, which showed that this molecule is stabilized by an intramolecular hydrogen bond between the carbonyl oxygen and the NH hydrogen to form a planar six-membered ring and by nonbonded interaction of ortho methoxy oxygen with the carbonyl oxygen or the selenium atoms. 4-Methoxybenzoyl and 4-methoxythiobenzoyl N-(4-methylphenyl)carbamoyl sulfides (4 and 5) were shown by X-ray crystallography to similarly have a planar intramolecular six-membered ring formed by a hydrogen bond between the carbonyl oxygen or thiocarbonyl sulfur and NH hydrogen atoms. The tautomers [RC(=E)SC(=NR')OH; E = O or S] of 4 and 5 also were detected spectroscopically. The recations of 3h (R = 4-MeOC6H4, R' = Ph) with sodium methoxide and p-toluidine gave sodium selenocarboxylate and the corresponding amides and urea as main products, respectively.
- Kageyama, Hideki,Tani, Kazuyasu,Kato, Shinzi,Kanda, Takahiro
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p. 250 - 258
(2007/10/03)
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- KINETICS AND MECHANISM OF THE AMINOLYSIS OF BENZOIC ANHYDRIDES
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Nucleophilic substitution reactions of benzoic anhydrides, in which one of the rings is substituted, with anilines were investigated in methanol.The product-formation step coincides with the rate-limiting step so that the two rate constants, kXY and kXZ, for the competitive reaction pathways can be dissected.The two cross-interaction constants, ρXY and ρXZ, especially an unusually large magnitude of the latter, indicate that the reaction proceeds by a frontside SN2 attack on either one of the carbonyl carbon with a strong interaction between the nucleophile (X) and the leaving group (Z).The mechanism is also supposed by the trends in the activation parameters.
- Lee, Byung Choon,Yoon, Ji Hyun,Lee, Cheal Gyu,Lee, Ikchoon
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p. 273 - 279
(2007/10/02)
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- Anticonvulsant activity of some 4-methoxy- and 4-chlorobenzanilides
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A series of mono-, di-, and trimethylated derivatives of 4-chloro- and 4-methoxybenzanilide was synthesized and evaluated for anticonvulsant activity. This series was prepared in the course of studies designed to examine the relationship between anticonvulsant effects and benzamide structure. The compounds were tested in mice against seizures induced by maximal electroshock (MES) and pentylenetetrazole (scMet), as well as with the rotorod assay for neurologic deficit. In mice dosed intraperitoneally, 4-methoxy-2, 6-dimethylbenzanilide (4) showed a median anticonvulsant potency (ED50) of 18.58 mg/kg in the MES test and a median toxicity (TD50) of 133.72 mg/kg in the rotorod toxicity assay, yielding a protective index (PI = TD50/ED50) of 7.2. In mice dosed orally with 4, the anti-MES ED50 was 27.40 mg/kg and the TD50 dose was determined to be 342.58 mg/kg, resulting in a protective index of 12.5.
- Clark,McMillian
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p. 220 - 222
(2007/10/02)
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- Mechanisms for the Reactions of Nitrones with Aroyl Chlorides
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Reaction of nitrones with equivalent quatities of aroyl chlorides in anhydrous dioxane containing triethylamine aields N,N-diacylamines.Treatment of nitrons with 18O-labeled benzoyl chloride under these conditions forms N,N-diacylamines with the 18O label distributed equally between the two acyl groups.Reaction of nitrones with equivalent or excess amounts of aroyl chlorides in anhydrous dioxane in the absence of triethylamine brings about isomerization of the nitrones to amides. α-Phenyl-N-(p-tolyl)nitrone treated with benzoyl chloride leads to an amide containing 50percent of the 18O label.Both reactions can be rationalized on the basis of the formation of aroyloxy(benzylidene)ammonium chlorides which undergo elimination of acid anions or acid to yield nitrillium ions.Addition of the acid anions or acids to the nitrillium ions affords the precursors to the N,N-diacylamines or isomerized amides, respectively.
- Heine, Harold W.,Zibuck, Regina,VandenHeuvel, William J. A.
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p. 3691 - 3694
(2007/10/02)
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- A Novel Synthesis of 3-Aryl-1,2,4-benzotriazines via N-Phenylsulfonyl-N''-arylbenzamidrazones
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3-Aryl-1,2,4-benzotriazines were obtained in good yields by the mercury(II) oxide-oxidation of N-phenylsulfonyl-N''-arylbenzamidrazones prepared from N-(phenylsulfonyl)benzohydrazonoyl chlorides and anilines.From the synthetic viewpoint for benzotriazines, this method may be of high utility on account of the availability of starting materials and higher yields.
- Ito, Suketaka,Tanaka, Yumo,Kakehi, Akikazu
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p. 859 - 864
(2007/10/02)
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