- Photophysics of Perylene Diimide Dianions and Their Application in Photoredox Catalysis
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The two-electron reduced forms of perylene diimides (PDIs) are luminescent closed-shell species whose photochemical properties seem underexplored. Our proof-of-concept study demonstrates that straightforward (single) excitation of PDI dianions with green
- Li, Han,Wenger, Oliver S.
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supporting information
(2021/12/23)
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- Influence of Steric Effect on the Pseudo-Multicomponent Synthesis of N-Aroylmethyl-4-Arylimidazoles
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A pseudo-three-component synthesis of N-aroylmethylimidazoles 3 with three new C–N bonds formed regioselectively under microwave conditions was developed. Products were obtained by reacting two equivalents of aroylmethyl bromide (ArCOCH2 Br, 1) with the appropriate amidine salt (RCN2 H3.HX, 2) and with K2 CO3 as a base in acetonitrile. The bicomponent reaction also occurred, giving the expected 4(5)-aryl-1H-imidazoles 4. Notably, the ratio of products 3 and 4 is governed by steric factors of the amidine 2 (i.e., R = H, CH3, Ph). Therefore, a computational study was carried out to understand the reaction course regarding product ratio (3/4), regioselectivity, and the steric effects of the amidine substituent group.
- Elejalde-Cadena, Nerith Rocio,García-Olave, Mayra,Figueroa, David,Vidossich, Pietro,Miscione, Gian Pietro,Portilla, Jaime
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- Cobalt-Catalyzed Reductive C-O Bond Cleavage of Lignin β-O-4 Ketone Models via in Situ Generation of the Cobalt-Boryl Species
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An efficient and mild method for reductive C-O bond cleavage of lignin β-O-4 ketone models was developed to afford the corresponding ketones and phenols with PDI-CoCl2 as the precatalyst and diboron reagent as the reductant. The synthetic utility of the methodology was demonstrated by depolymerization of a polymeric model and gram-scale transformation. Mechanistic studies suggested that this transformation involves steps of carbonyl insertion, 1,2-Brook type rearrangement, β-oxygen elimination, and rate-limiting regeneration of the catalytic active Co-B species.
- Gao, Kecheng,Xu, Man,Cai, Cheng,Ding, Yanghao,Chen, Jianhui,Liu, Bosheng,Xia, Yuanzhi
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supporting information
p. 6055 - 6060
(2020/08/12)
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- Sulfur-mediated difunctionalization of internal and terminal alkynes for the synthesis of α-acetoxy ketones
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The sulfur-mediated difunctionalization of alkynes is reported to give α-acetoxy ketones in a one-pot operation under mild conditions with 19–92% yield. By using wet potassium acetate as both the aqueous base and nucleophilic reagent, both terminal alkynes and internal alkynes could be converted into the α-acetoxy ketone products.
- Li, Pingfan,Zhang, Zhong
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- Imidazolium-Based Ionic Network as a Robust Heterogeneous Catalyst in Synthesis of Phenacyl Derivatives
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A new imidazolium-based poly(ionic liquid) has been synthesized and used as a robust heterogeneous catalyst for the preparation of phenacyl derivatives by an SN2 reaction of different phenacyl bromides with a broad range of nucleophiles. The products are obtained in high yields under mild conditions. The catalyst can be recycled efficiently.
- Kakesh,Sayyahi,Badri,Tahanpesar
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p. 1218 - 1220
(2019/07/16)
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- PhI(OAc)2-promoted umpolung acetoxylation of enamides for the synthesis of α-acetoxy ketones
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Umpolung is a fundamental concept in organic chemistry, which provides an alternative strategy for the synthesis of target compounds which were not easily accessible by conventional methods. Herein, a mild and efficient PhI(OAc)2-promoted umpolung acetoxylation reactions of enamides was developed for the synthesis of α-acetoxy ketones. The reaction tolerates a wide range of functional groups and affords α-acetoxy ketones in good to excellent yields. PhI(OAc)2 serves as a source of acetoxy in the reaction.
- Chen, Ming,Zhang, Wei,Ren, Zhi-Hui,Gao, Wen-Yun,Wang, Yao-Yu,Guan, Zheng-Hui
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p. 761 - 768
(2017/06/05)
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- Fine Tuning the Redox Potentials of Carbazolic Porous Organic Frameworks for Visible-Light Photoredox Catalytic Degradation of Lignin β-O-4 Models
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We report a facile approach to fine tune the redox potentials of π-conjugated porous organic frameworks (POFs) by copolymerizing carbazolic electron donor (D) and electron acceptor (A) based comonomers at different ratios. The resulting carbazolic copolymers (CzCPs) exhibit a wide range of redox potentials that are comparable to common transition-metal complexes and are used in the stepwise photocatalytic degradation of lignin β-O-4 models. With the strongest oxidative capability, CzCP100 (D:A = 0:100) exhibits the highest efficiency for the oxidation of benzylic β-O-4 alcohols, while the highly reductive CzCP33 (D:A = 66:33) gives the highest yield for the reductive cleavage of β-O-4 ketones. CzCPs also exhibit excellent stability and recyclability and represent a class of promising heterogeneous photocatalysts for the production of fine chemicals from sustainable lignocellulosic biomass.
- Luo, Jian,Zhang, Xiang,Lu, Jingzhi,Zhang, Jian
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p. 5062 - 5070
(2017/08/17)
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- Novel and efficient transformation of enamides into α-acyloxy ketones via an acyl intramolecular migration process
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Hydrogen peroxide and anhydride mediated transformation of enamides to afford substituted α-acyloxy ketones is described. This transition-metal-free cascade reaction has a broad substrate scope and high efficiency. The acyl intramolecular migration procedure successfully achieved this acyloxylation process under mild conditions and increased the atom efficiency.
- Zhou, Xiaoqiang,Ma, Haojie,Cao, Jinhui,Liu, Xingxing,Huang, Guosheng
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supporting information
p. 10070 - 10073
(2016/11/06)
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- Aerobic Oxidation of Olefins and Lignin Model Compounds Using Photogenerated Phthalimide-N-oxyl Radical
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A metal-free protocol to generate phthalimide-N-oxyl (PINO) radicals from N-hydroxyphthalimide (NHPI) via a photoinduced proton-coupled electron transfer process is reported. Using donor-substituted aromatic ketones, such as 4,4′-bis(diphenylamino)benzophenone (DPA-BP), PINO radicals are efficiently produced and subsequently utilized to functionalize olefins to afford a new class of alkyl hydroperoxides. The DPA-BP/NHPI/O2 photocatalytic system exhibits high efficiency toward the aerobic oxidation of β-O-4 lignin models.
- Luo, Jian,Zhang, Jian
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p. 9131 - 9137
(2016/10/17)
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- Integration of aqueous biphasic with magnetically recyclable systems: Polyethylene glycol-grafted Fe3O4 nanoparticles catalyzed phenacyl synthesis in water
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The present work trends to define an efficient phenacyl catalytic synthesis method employing a new nano-magnetite-supported organocatalyst. Polyethylene glycol (PEG) was bonded successfully onto silica coated ferrite and the resultant nanoparticles (PEG@SiO2@Fe3O4) characterized by fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), thermal gravimetric analysis (TGA), vibrating sample magnetometry (VSM), energy dispersive X-ray analysis (EDAX) and X-ray diffraction (XRD) that exhibited a good catalytic activity in the reaction. The nanoparticles could be easily separated from the reaction mixture by an external magnet and reused in seven reaction cycles without significant loss of activity.
- Amini, Atefeh,Sayyahi, Soheil,Saghanezhad, Seyyed Jafar,Taheri, Narges
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- Synthesis of 2-Aminoazoles from Thioesters via α-Heterosubstituted Ketones by Copper-Mediated Cross-Coupling
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Facile synthesis of a variety of α-heterosubstituted ketones under mild conditions was achieved by copper-mediated cross-coupling of thioesters with functionalized organostannanes. Application of this coupling methodology provided a concise pathway for the conversion of carboxylic acids to 2-aminoimidazoles, 2-aminothiazoles, and 2-aminooxazoles via thioesters in practical yields.
- Kobayashi, Hiroyuki,Eickhoff, John A.,Zakarian, Armen
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p. 9989 - 9999
(2015/11/03)
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- Iron-Catalyzed Dioxygenation of Alkenes and Terminal Alkynes by using (Diacetoxyiodo)benzene as Oxidant
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An iron-catalyzed syn-diacetoxylation of alkenes and 1,2-oxyacetoxylation of terminal alkynes has been developed using (diacetoxyiodo)benzene as oxidant. A broad range of internal and terminal alkenes, including electron-rich as well as electron-deficient alkenes, gave the desired products in good to excellent yields with high diastereoselectivity (up to >99:1 dr). In addition the high catalytic activity of iron catalysis for the 1,2-oxyacetoxylation of terminal alkynes is also reported. The roles of catalyst, oxidant and other reaction parameters were evaluated for activation of the unsaturated bond.
- Srinivas,Rawat, Vikas S.,Sreedhar, Bojja
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supporting information
p. 3587 - 3596
(2016/01/25)
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- Flexible stereoselective functionalizations of ketones through umpolung with hypervalent iodine reagents
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The functionalization of carbonyl compounds in the α-position has gathered much attention as a synthetic route because of the wide biological importance of such products. Through polarity reversal, or "umpolung", we show here that typical nucleophiles, such as oxygen, nitrogen, and even carbon nucleophiles, can be used for addition reactions after tethering them to enol ethers. Our findings allow novel retrosynthetic planning and rapid assembly of structures previously accessible only by multistep sequences. A Nu approach: An efficient α-functionalization of ketones with a range of simple and useful nucleophiles is possible by using hypervalent iodine reagents (see scheme; Nu′ can be the Nu itself or a protected form of this nucleophile group).
- Mizar, Pushpak,Wirth, Thomas
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p. 5993 - 5997
(2014/06/10)
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- A photochemical strategy for lignin degradation at room temperature
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The development of a room-temperature lignin degradation strategy consisting of a chemoselective benzylic oxidation with a recyclable oxidant ([4-AcNH-TEMPO]BF4) and a catalytic reductive C-O bond cleavage utilizing the photocatalyst [Ir(ppy)2(dtbbpy)]PF6 is described. This system was tested on relevant lignin model substrates containing β-O-4 linkages to generate fragmentation products in good to excellent yields.
- Nguyen, John D.,Matsuura, Bryan S.,Stephenson, Corey R. J.
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supporting information
p. 1218 - 1221
(2014/02/14)
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- Straightforward and highly efficient synthesis of α-acetoxy ketones through gold-catalyzed intermolecular oxidation of terminal alkynes
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A variety of terminal alkynes were efficiently converted into the corresponding α-acetoxy ketones through gold-catalyzed intermolecular oxidation in the presence of 8-methylquinoline 1-oxide as the oxidant. The reaction probably proceeds through an α-oxo gold carbene intermolecular O-H insertion.
- Wu, Chao,Liang, Zhiwu,Yan, Dong,He, Weimin,Xiang, Jiannan
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p. 2605 - 2611
(2013/09/24)
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- Silver(I)-catalyzed reaction of terminal alkynes with (diacetoxyiodo) benzene: A convenient, efficient and clean preparation of α-acetoxy ketones
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Silver(I)-catalyzed reaction of terminal alkynes with (diacetoxyiodo) benzene in wet acetonitrile at room temperature afforded the corresponding α-acetoxy ketones in 55-93% yields. The salient features of this reaction are the effective utilization of PhI
- Deng, Guisheng,Luo, Jing
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p. 5937 - 5944
(2013/07/27)
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- Activity of 6-aryl-pyrrolo[2,3-d]pyrimidine-4-amines to Tetrahymena
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A series 6-aryl-pyrrolo[2,3-d]pyrimidine-4-amines (43 compounds), some of which are epidermal growth factor tyrosine kinase inhibitors, were tested for their protozoal toxicity using an environmental Tetrahymena strain as model organism. The protozoacidal activity of the analogues was found to be highly dependent on a 4-hydroxyl group at the 6-aryl ring, and a chiral 1-phenylethanamine substituent in position 4. Further, the potency was affected by the aromatic substitution pattern of the phenylethanamine: the unsubstituted, the meta-fluoro and the para-bromo substituted derivatives had the lowest minimum protozoacidal concentrations (8-16 μg/mL). Surprisingly, both enantiomers were found to have high potency suggesting that this compound class could have several modes of action. No correlation was found between the compounds protozoacidal activity and the in vitro epidermal growth factor receptor tyrosine kinase inhibitory potency. This suggests that the observed antimicrobial effects are related to other targets. Testing towards a panel of kinases indicated several alternative modes of action.
- Kaspersen, Svein Jacob,Hoff, Bard Helge,Sundby, Eirik,Charnock, Colin
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p. 35 - 41,7
(2020/07/30)
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- β-cyclodextrin immobilized onto dowex resin: A unique microvessel and heterogeneous catalyst in nucleophilic substitution reactions
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The catalytic activity of β-cyclodextrin immobilized on Dowex resin as an efficient solid-liquid phase transfer catalyst was developed for the synthesis of alkyl thiocyanates and phenacyl derivatives in water. The nucleophilic substitution reactions were performed under mild reaction condition and gave the products in excellent yields. Furthermore, the catalyst could be recycled by facile separation without any loss of activity.
- Kiasat, Ali Reza,Zarinderakht, Nasrollah,Sayyahi, Soheil
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experimental part
p. 699 - 702
(2012/05/05)
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- A sustainable byproduct catalyzed domino strategy: Facile synthesis of α-formyloxy and acetoxy ketones via iodination/nucleophilic substitution/hydrolyzation/oxidation sequences
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The sustainable byproduct catalyzed domino strategy has been performed for the facile synthesis of α-formyloxy and acetoxy ketones via iodination/nucleophilic substitution/hydrolyzation/oxidation sequences from simple and readily available aromatic ketone
- Zhu, Yan-Ping,Gao, Qing-He,Lian, Mi,Yuan, Jing-Jing,Liu, Mei-Cai,Zhao, Qin,Yang, Yan,Wu, An-Xin
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supporting information; experimental part
p. 12700 - 12702
(2012/01/03)
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- Biocatalytic reduction of prochiral aromatic ketones to optically pure alcohols by a coupled enzyme system for cofactor regeneration
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A simple, highly efficient, and economical biphasic cell-free system was developed for biocatalytic reduction of prochiral aromatic ketones to furnish enantiopure alcohols. This system is characterized by using endogenous enzymes of the cell-free extract to form enzyme-coupled NADPH recycling system. Besides, it offered much higher productivity than whole cells and greatly simplified the preparation process of biocatalysts in comparison with isolated enzymes. Various prochiral aromatic ketones, especially α-substituted acetophenone derivatives, were reduced to chiral alcohols with excellent enantiomeric excess (ee) and moderate to good yield by this cell-free system.
- Yan, Zhen,Nie, Yao,Xu, Yan,Liu, Xiang,Xiao, Rong
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supporting information; experimental part
p. 999 - 1002
(2011/03/21)
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- Copper(II) and 2,2'-biimidazole-promoted novel reaction of 4,4,4-trifluoro-1-phenylbutane-1,3-diones with iodobenzene diacetate
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A new and efficient way was developed to carry out the reaction of 4,4,4-trifluoro-1-phenylbutane-1,3-dione with iodobenzene diacetate under the assistance of Cu(II) and 2,2'-biimidazole at a low temperature in excellent yield. 2-Acetoxyacetophenone was obtained unexpectedly.
- Zhou, Chunmei,Zeng, Runsheng,Zou, Jianping
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experimental part
p. 294 - 298
(2010/10/21)
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- One-pot synthesis of α-formyloxy ketones from enolizable ketones
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One-pot synthesis of α-formyloxy tones as well as α-acetoxy ketones from enolizable ketones and [hydroxy(tosyloxy) iodo] benzene (HTIB)/polymer supported [hydroxy(tosyloxy) iodo] benzene (PSHTIB) in N,N-dimethylformamide (DMF)/N, N-dimethylacetamide (DMA)
- Kumar, Sunil,Kumar, Ashok,Gupta, Rakesh K.,Kumar, Devinder
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p. 338 - 345
(2008/04/01)
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- Synthesis and biological evaluation of quinoline salicylic acids as P-selectin antagonists
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Leukocyte recruitment of sites of inflammation and tissue injury involves leukocyte rolling along the endothelial wall, followed by firm adherence of the leukocyte, and finally transmigration of the leukocyte across cell junctions into the underlying tissue. The initial rolling step is mediated by the interaction of leukocyte glycoproteins containing active moieties such as sialyl Lewisx (sLex) with P-selectin expressed on endothelial cells. Consequently, inhibition of this interaction by means of a small molecule P-selectin antagonist is an attractive strategy for the treatment of inflammatory diseases such as arthritis. High-throughput screening of the Wyeth chemical library identified the quinoline salicylic acid class of compounds (1) as antagonists of P-selectin, with potency in in vitro and cell-based assays far superior to that of sLex. Through iterative medicinal chemistry, we identified analogues with improved P-selectin activity, decreased inhibition of dihydrooratate dehydrogenase, and acceptable CYP profiles. Lead compound 36 was efficacious in the rat AIA model of rheumatoid arthritis.
- Kaila, Neelu,Janz, Kristin,DeBernardo, Silvano,Bedard, Patricia W.,Camphausen, Raymond T.,Tam, Steve,Tsao, Desirée H.H.,Keith Jr., James C.,Nickerson-Nutter, Cheryl,Shilling, Adam,Young-Sciame, Ruth,Wang, Qin
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- Chemoenzymatic synthesis of enantiomerically pure 1,2-diols employing immobilized lipase in the ionic liquid [bmim]PF6
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Significantly enhanced enantioselectivity in the enzymatic kinetic resolution of 1,2-diols employing immobilized lipase from Pseudomonas cepacia (PS-C, 'Amano') results from the use of the ionic liquid [bmim]PF6 as reaction medium.
- Kamal, Ahmed,Chouhan, Gagan
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p. 8801 - 8805
(2007/10/03)
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- Ketone precursors for organoleptic compounds
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The invention discloses ketones of formula I: wherein, Y is an optionally substituted alkyl, cycloalkyl, or cycloalkylalkyl, wherein each alkyl group is straight or branched and each alkyl and cycloalkyl group is saturated or unsaturated; R1is hydrogen or a C1-6alkyl group that is substituted, saturated or unsaturated, straight or branched; A is a chromophoric substituted aromatic ring or ring system; n is an integer; and with the proviso that formula I is not 2-ethoxy-1-phenyl-ethanone. These compositions are useful for the delivery of organoleptic compounds, especially of flavors, fragrances, masking agents and antimicrobial compounds.
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- Synthesis of α-acetoxy and formyloxy ketones by thallium(III) promoted α-oxidation
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Treatment of ketones with thallium(III) triflate in amide solvents at 60°C for 30 min followed by addition of small amounts of H2O cleanly provided the corresponding α-acyloxy ketones.
- Lee,Jin,Choi
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p. 956 - 957
(2007/10/03)
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- Acid-catalyzed solvolysis of polyenol ethers. III. Effect of the alkoxy moiety
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The dependence of the solvolysis of polyenol ethers on the nature of the alkoxy moiety has been studied. A new reaction path, leading to the formation of ω-hydroxy (methoxy) substituted aldehydes and -esters, was established. The proposed reaction pathway (scheme 6) is initiated by an electron transfer from the polyenol ether to molecular oxygen, followed by combination of the two radicals to a peroxide zwitterion. Upon protonation, solvent adds to the ω-carbon atom of the polyene to give an intermediate that can either loose water to form an ester, or loose the alkoxy moiety to give an aldehyde. This mechanism is believed to be involved in the strong mutagenic activity displayed by many polyenol ethers, including the natural mutagen fecapentaene-12.
- Nieuwenhuis, Saskia A. M.,Vertegaal, Louis B. J.,De Zoete, Marian C.,Van Der Gen, Arne
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p. 13207 - 13230
(2007/10/02)
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- Metal-Metal Exchange of α-Metallo Ketones. Novel Formation of α-Acyl Anion and α-Keto Carbonium Ion Equivalents from (Aryl)phenacyl TlIII, PbIV, and HgII Systems
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The novel class of α-metallo ketones RCOCH2TlIIItolyl(OCOCF3) where R = phenyl, substituted phenyl, thienyl, pyridinyl, and tert-butyl have been synthesized and characterized by 1H NMR and 13C NMR.These compounds serve as anion equivalents in the TiCl4-mediated aldol condensation.Metal-metal exchange with iodosylbenzene or lead tetraacetate leads to α-nucleophilic substitution derived from the formal α-keto carbonium ion equivalent.The corresponding p-CH3OC6H4COCH2PbIVC6H4OCH3-p-(OCOCH3)2 and (p-CH3OC6H4COCH2)2HgII analogues were synthesized and shown to likewise behave as either enolate anion or α-keto carbonium ion equivalents upon metal-metal exchange with TiIV, PbIV, or IIII.The importance of this work is that the range of reactivity of α-metallo ketones may be selectively adjusted by metal-metal or metal-metalloid exchange.
- Moriarty, Robert M.,Penmasta, Raju,Prakash, Indra,Awasthi, Alok K.
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p. 1022 - 1025
(2007/10/02)
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- Reactions of Substituted Phenacyl Bromides with Various Bases: p-Methyl- and p-Methoxyphenacyl Bromide. II
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The products obtained from the reaction of p-methyl- and p-methoxyphenacyl bromide with various bases are described.
- Baghdadchi, Jamil,Chan, Albert P.,Hutchinson, James H.
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p. 973 - 974
(2007/10/02)
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- SYNTHESIS OF 1,4-DIKETONES BY THE COUPLING REACTION OF TRIMETHYLSILYL ENOL ETHERS WITH LEAD TETRAACETATE
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Synthesis of 1,4-diketones in good yields was achieved by the coupling reaction of the trimethylsilyl enol ethers of acetophenone,thiophene or furan with lead tetraacetate in dry dichloromethane and tetrahydrofuran at -78 degC.
- Moriarty, Robert M.,Penmasta, Raju,Prakash, Indra
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p. 873 - 876
(2007/10/02)
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- Facile synthesis of glycol metabolites of phenethylamine drugs
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High yields of potential glycol metabolites of p-synephrine, epinephrine, octopamine, and normacromerine can be obtained from the readily available monosubstituted and disubstituted acetophenones. The general procedure involves alpha-bromination followed by displacement with acetate ion and reduction with lithium aluminum hydride. Yields ranged from 46 to 91%. Furthermore, the procedure minimizes some problems inherent in aromatic glycol synthesis which include dimerization and pinacol-pinacolone rearrangement.
- Holshouser,Kolb
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p. 619 - 621
(2007/10/02)
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- The Reaction of Acetophenones with Manganese(III) Acetate
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The reaction of 4'-methoxyacetophenone with manganese(III) acetate in the presence of ammonium chloride yielded 2-chloro-4'-methoxyacetophenone (2a) and 2,2-dichloro-4'-methoxyacetophenone (3a).The reaction of 2a with these reagents gave 3a, 4'-methoxy-2,2,2-trichloroacetophenone and 1,4-bis(4-methoxyphenyl)2,2,3,3,-tetrachloro-1,4-butanedione (8a).The reactions of 2a and 2-bromoacetophenone with manganese(III) acetate yielded the corresponding 2,3-dihalo-1,4-diphenyl-1,4-butanediones, 1,4-diphenyl-2-halo-2-butene-1,4-diones, 2,3-dihalo-2-butene-1,4-diones, 2,2-dibromoacetophenone, and 8a.The reaction pathways are discussed.
- Kurosawa, Kazu,Yamaguchi, Katsutoshi
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p. 1757 - 1760
(2007/10/02)
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