- Zinc(II)-Catalyzed Synthesis of Secondary Amides from Ketones via Beckmann Rearrangement Using Hydroxylamine-O-sulfonic Acid in Aqueous Media
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A zinc(II)-catalyzed single-step protocol for the Beckmann rearrangement using hydroxylamine-O-sulfonic acid (HOSA) as the nitrogen source in water was developed. This direct method efficiently produces secondary amides under open atmosphere in a pure form after basic aqueous workup. It isenvironmentally benign and operationally simple.
- Verma, Saumya,Kumar, Puneet,Khatana, Anil K.,Chandra, Dinesh,Yadav, Ajay K.,Tiwari, Bhoopendra,Jat, Jawahar L.
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p. 3272 - 3276
(2020/11/02)
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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)
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- 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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- SO2F2-Activated Efficient Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
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A novel, mild and practical protocol for the efficient activation of the Beckmann rearrangement utilizing the readily available and economical sulfuryl fluoride (SO2F2 gas) has been developed. The substrate scope of the operationally simple methodology has been demonstrated by 37 examples with good to nearly quantitative isolated yields (over 90 % yield in most cases) in a short time, including B(OH)2, COOH, NH2, and OH substituted substrates. A tentative mechanism was proposed involving formation and elimination of key intermediate, sulfonyl ester.
- Zhang, Guofu,Zhao, Yiyong,Xuan, Lidi,Ding, Chengrong
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p. 4911 - 4915
(2019/07/31)
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- General rhodium-catalyzed oxidative cross-coupling reactions between anilines: Synthesis of unsymmetrical 2,2′-diaminobiaryls
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Described herein is a dual chelation-assisted RhCl3-catalyzed oxidative C-H/C-H cross-coupling reaction of aniline derivatives. The highlight of this methodology is the chemo- and regioselective cross-coupling between electronically similar substrates, which represents a highly challenging task in oxidative Ar-H/Ar-H cross-coupling reactions. Furthermore, this Cp?-free catalytic reaction tolerates a range of functional groups and requires only a low molar ratio of coupling partners. These features expedite the synthesis of unsymmetrical 2,2′-diaminobiaryls.
- Shi, Yang,Liu, Jiahui,Yang, Yudong,You, Jingsong
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supporting information
p. 5475 - 5478
(2019/05/16)
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- PtCl4-catalyzed cyclization of N-acetyl-2-alkynylanilines: A mild and efficient synthesis of N-acetyl-2-substituted indoles
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An efficient synthesis of N-acetyl-2-substituted indole derivatives via direct intramolecular hydroamination of N-acetyl-2-alkynylaniline derivatives was developed. The reaction could be applied to a wide range of substrates employing only 1–2 mol% of PtCl4 as the catalyst to furnish the desired indole products in moderate to excellent yields. The current protocol is efficient, reliable and scalable, and could serve as an important tool for convenient and rapid access to this important class of N-heterocyclic skeleton from readily available substrates.
- Chaisan, Nattawadee,Kaewsri, Wilailak,Thongsornkleeb, Charnsak,Tummatorn, Jumreang,Ruchirawat, Somsak
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supporting information
p. 675 - 680
(2018/01/18)
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- Selective, Catalytic, and Metal-Free Coupling of Electron-Rich Phenols and Anilides Using Molecular Oxygen as Terminal Oxidant
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Selective oxidative homo- and cross-coupling of electron-rich phenols and anilides was developed using nitrosonium tetrafluoroborate as a catalyst. Oxidative coupling of phenols revealed unusual selectivities, which translated into the unprecedented synthesis of inverse Pummerer-type ketones. Mechanistic studies suggest that oxidative coupling of phenols and anilides shares a common pathway via homolytical heteroatom-hydrogen bond cleavage. Nitrosonium salt catalysis was applied for cross-dehydrogenative coupling initiated by generation of heteroatom-centered radicals.
- Bering, Luis,Vogt, Melina,Paulussen, Felix M.,Antonchick, Andrey P.
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supporting information
p. 4077 - 4080
(2018/07/15)
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- Aerobic oxidative homocoupling reaction of anilides using heterogeneous metal catalysts
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We have developed a heterogeneous catalytic oxidative homocoupling reaction of dimethoxyanilides under an oxygen atmosphere. The resulting homo-dimers are useful for the construction of heterocycles, demonstrating the potential of heterogeneous metal catalysts.
- Fujimoto, Shigenobu,Matsumoto, Kenji,Iwata, Takayuki,Shindo, Mitsuru
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supporting information
p. 973 - 976
(2017/02/15)
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- Biomimetic oxidation of acetaminophen prodrugs catalyzed by iron porphyrins: Effect of nitrogen and thiolate axial ligands on drug and metabolite formation
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Metalloporphyrins (MP) are often employed in biomimetic catalysis due to their structural and functional similarity to the heme prosthetic group of oxygenating enzymes. In these enzymes, the iron porphyrin is primarily protein-bound at the active site by cysteine (cytochrome P450, CYP), histidine (peroxidase), and tyrosine (catalase), acting as axial ligands. The diverse functionality and variable oxidizing power exhibited by different oxygenating enzymes is [in part] attributed to the ligating amino acid, and the relationship between iron and the heteroatom. Attempts to mimic this relationship by developing MP systems that behave similarly to CYP enzymes have mainly focused on incorporating nitrogen (N)-heterocycles. Although it is widely known that different enzyme families favor distinctive products, sulfur is easily oxidized and prone to form disulfide bonds, and as such, thiolates for the most part remain unexplored. Herein, we report our findings from the biomimetic oxidation of phenacetin, methacetin, and acetanilide by meta-chloroperoxybenzoic acid (m-CPBA), catalyzed by hindered iron (III) porphyrins that are chelated by different axial ligands. Nine axial ligands that vary in pKa (2.8-11.2), size, and heteroatomic identity were examined, to more accurately determine the factors that contribute to function and effect. The [three] thiolate ligands afforded the greatest yields of acetaminophen in the majority of cases. Furthermore, nitrogen- and sulfur-containing ligands were observed to promote different reaction pathways, regardless of pKa or ligand size.
- Chapman, Chiara M.,Pruneau, John M.,Laverack, Chloe A.,Dutton, Andrew S.,Jones, Graham B.
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p. 204 - 215
(2015/12/05)
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- AIBN-promoted amidation of anilines with 1, 3-diketones via oxidative cleavage of C–C bond under aerobic conditions
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N-Acylation of anilines with 1, 3-diketones promoted by AIBN (2-2′-azoisobutyronitrile) under metal-free and peroxide-free conditions in the presence of molecular oxygen as oxidant has been described. This protocol proceeds by the oxidative cleavage of C–C bond with simultaneous intermolecular C–N bond formation under mild conditions.
- Rao, Sadu Nageswara,Mohan, Darapaneni Chandra,Adimurthy, Subbarayappa
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p. 4889 - 4894
(2016/07/18)
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- Selective N-acetylation of aromatic amines using acetonitrile as acylating agent
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A method for N-acetylation of amines has been developed using acetonitrile as an acylating agent and in situ generated trimethylsilyl iodide as the catalyst under microwave heating condition. The reaction is selective toward aromatic amines while aliphatic amines remain intact. The process eliminates the requirement of toxic acylating reagents like acetic anhydride and acetyl chloride.
- Saikia, Ujwal Pratim,Hussain, Farhaz L.,Suri, Mrinaly,Pahari, Pallab
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supporting information
p. 1158 - 1160
(2016/03/09)
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- Photo-Fries rearrangement of aryl acetamides: Regioselectivity induced by the aqueous micellar green environment
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Photochemical reactions tend to give more than one photoproduct. However, such a reaction can be a powerful synthetic tool when it is possible to conduct it in regioselective conditions yielding a single photoproduct. Water-surfactant solutions as reaction media can be considered as an approach in this context because they show products with different features than those from isotropic solutions. Here we describe results obtained from studying the effect on the prototypical photoreaction, known as the photo-Fries reaction of several substituted acetanilides and α-naphthyl acetamide within surfactant micelles (ionic and non-ionic micelles). This reaction involves homolytic cleavage of a C-N bond to yield a singlet radical pair. The surfactant micelles control the rotational and translational mobility of the radical pair, resulting in noticeable photoproduct selectivity.
- Iguchi, Daniela,Erra-Balsells, Rosa,Bonesi, Sergio M.
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p. 105 - 116
(2016/01/20)
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- Synthesis, biological evaluation and mechanism study of a class of cyclic combretastatin A-4 analogues as novel antitumour agents
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In the course of our search for novel antitumor agents, a series of cyclic combretastatin A-4 (CA-4) analogues bearing an amide group, A-B or B-C ring condensation, and CC or CN bond in the B ring were designed, synthesized and identified as new microtubule inhibitors. The structure-activity relationship (SAR) studies showed that the hexa-cyclic compounds bearing B-C ring condensation, containing a CC bond in the B ring (4a) provided excellent antiproliferative activities at nanomolar concentrations against various cancer cell lines (IC50 = 46-80 nM). 4a inhibited tubulin assembly at a micromolar range (IC50 = 2.56 ± 0.15 μM) as evidenced by a molecular docking study, which revealed that 4a exerted tubulin polymerisation inhibitory activity by binding to the colchicine binding site of tubulin. Further molecular biology studies showed that 4a disrupted intracellular microtubule polymerisation and thus induced G2/M phase arrest and apoptotsis in A549 cells. Altogether, these results we obtained can guide the design of novel potent molecules for future development.
- Yan, Jun,Pang, Yanqing,Chen, Jie,Sheng, Jianfei,Hu, Jinhui,Huang, Ling,Li, Xingshu
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p. 98527 - 98537
(2015/12/04)
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- Synthesis and biological evaluation of new rhodanine analogues bearing 2-chloroquinoline and benzo[h]quinoline scaffolds as anticancer agents
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Several rhodanine derivatives (9-39) were synthesized for evaluation of their potential as anticancer agents. Villsmeier cyclization to synthesize aza-aromatic aldehydes, rhodanine derivatives preparation and Knoevenagel type of condensation between the rhodanines and aza-aromatic aldehydes are key steps used for the synthesis of 31 compounds. In vitro antiproliferative activity of the synthesized rhodanine derivatives (9-39) was studied on a panel of six human tumor cell lines viz. HGC, MNK-74, MCF-7, MDAMB-231, DU-145 and PC-3 cell lines. Some of the compounds were capable of inhibiting the proliferation of cancer cell lines at a micromolar concentration. Six compounds are found to be potent against HGC cell lines; compound 15 is found to be active against HGC - Gastric, MCF7 - Breast Cancer and DU145 - Prostate Cancer cell lines; compound 39 is potent against MNK-74; four compounds are found to be potent against MCF-7 cell lines; three compounds are active against MDAMB-231; nine compounds are found to be potent against DU-145; three compounds are active against PC-3 cell lines. These compounds constitute a promising starting point for the development of novel and more potent anticancer agents in future.
- Ramesh, Vadla,Ananda Rao, Boddu,Sharma, Pankaj,Swarna,Thummuri, Dinesh,Srinivas, Kolupula,Naidu,Jayathirtha Rao, Vaidya
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p. 569 - 580
(2014/07/21)
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- Hypervalent iodine mediated synthesis of carbamate protected p-quinone monoimine ketals and p-benzoquinone monoketals
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A simple and efficient method for the synthesis of p-quinone monoimide ketals and p-benzoquinone monoketals by using a hypervalent iodine reagent, diacetoxyiodobenzene, has been developed. These two types of ketals are achieved from a single starting material by varying the reaction conditions.
- Bodipati, Naganjaneyulu,Peddinti, Rama Krishna
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body text
p. 4549 - 4553
(2012/07/14)
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- Synthesis and antimalarial activity of Baylis-Hillman adducts from substituted 2-chloroquinoline-3-carboxaldehydes
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Various quinoline carboxaldehydes were prepared from corresponding anilides using classical Vilsmeier-Haack reaction conditions and transformed into their Baylis-Hillman adducts. The synthesized Baylis-Hillman adducts were screened for their in vitro antimalarial activity against Plasmodium falciparum . Most of the compounds out of 21 compounds synthesized and screened exhibited substantial antimalarial activity. by Walter de Gruyter.
- Srihari, Ejjirothu,Kumar, Gangala Siva,Kumar, Chebolu Naga Sesha Sai Pavan,Seth, Ratnesh Kumar,Biswas, Sukla,Sridhar, Balasubramanian,Rao, Vaidya Jayathirtha
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scheme or table
p. 111 - 119
(2011/11/30)
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- Nitroethane in polyphosphoric acid: A new reagent for acetamidation and amination of aromatic compounds
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A new method of acetamidation of aromatic compounds based on their reaction with nitroethane in polyphosphoric acid has been developed. Upon the hydrolysis of acetamides during the reaction mixture workup, the corresponding amines can be obtained. Georg Thieme Verlag Stuttgart New York.
- Aksenov, Alexander V.,Aksenov, Nicolai A.,Nadein, Oleg N.,Aksenova, Inna V.
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experimental part
p. 2628 - 2630
(2010/12/18)
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- Synthesis of APTRA derivatives as building blocks for low-affinity fluorescent Ca2+ indicators
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A new method for the synthesis of trialkyl aminophenoltriacetates (APTRA triesters) and the functionalization of these into suitable building blocks for potential fully conjugated low-affinity fluorescent Ca2+ indicators are described. Georg Th
- Metten, Bert,Smet, Mario,Boens, Noel,Dehaen, Wim
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p. 1838 - 1844
(2007/10/03)
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- Acetamidoquinone and acetamidohydroxy derivatives as inhibitors for both dihydroxyacetamido epoxidase and dehydrogenase
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A series of monohydroxy and dihydroxyacetanilides, acetamidoquinones and bromoacetamidoquinones have been synthesised and tested as substrates and/or inhibitors of highly purified dihydroxyacetamido epoxidase (DHAE) and dihydroxy acetamido dehydrogenase (DHADH) from Streptomyces LL-C10337. None was found to act as substrates but many selectively inhibit the enzymes. Kinetic analysis has shown that all the compounds act as reversible competitive inhibitors with respect to the substrates 2,5-dihydroxyacetanilide and 2,3-epoxy-1,4-benzoquinone-5-acetanilide. Monohydroxy acetanilides showed weak inhibition to these enzymes compared to the dihydroxy derivatives while the more powerful inhibitors were the benzoquinoneacetanilide and its 5-bromo equivalent.
- Whiteley, Chris G.
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p. 1221 - 1227
(2007/10/03)
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- Production of benzophenone derivatives
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A method for producing a compound of the formula: wherein R is an acyl group or a silyl group, the rings A and B respectively may have one to four substituent(s), or a salt thereof, which comprists reacting a compound of the formula: wherein R has the same meaning as defined above, the ring A may have one to four substituents at the position(s) other than 2-position, or a salt thereof, with a compound of the formula: wherein Y is a hydroxyl group or a halogen atom, the ring B may have one to four substituent(s), or its salt, in the presence of a catalyst other than polyphosphonic acid. The method produces aminobenzophenone derivative of the formula (I) in a high purity, a high yield, with a conventional and commercially advantageous procedure.
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- Antiallergic (1H-tetrazol-5-yl)tetrazolo[1,5-a]quinolines and derivatives thereof
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(1H-Tetrazol-5-yl)tetrazolo[1,5-a]quinolines and related compounds which are useful as antiallergic agents are described herein. The compounds are prepared by the reaction of an appropriate halocyanoquinoline or isoquinoline with ammonium chloride and an
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- Photochemistry of Host-Guest Complex.III. Effect of Guest Cation on the Photoreactivity of Acetophenone Oxime Derivatives Having Crown Ether Moiety
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The syn-anti isomerisation of acetylbenzocrown ether oximes was stimulated by the complex-formation with sodium ion.The photolysis of these oximes gave mother ketones and amides through an oxaziridine intermediate.The photolysis of the oximes was depressed by the formation of host-guest complexes.Reactivity in the photolysis of the crown ether oximes corresponds to that 3,4-dimethoxyacetophenone oxime, whereas the reactivity of the complexed crown ether oxime with sodium ion corresponds to that of p-cyanoacetophenone oxime.Such behavior is explained by the change of the electronic properties of excited states of acetophenone oxime chromophore, which enhances the intersystem crossing.
- Tada, Masaru,Hirano, Hideki,Suzuki, Atsushi
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p. 2304 - 2308
(2007/10/02)
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