- Asymmetric meso-CF3-BODIPY dyes based on cycloalkanopyrroles
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New meso-CF3-substituted BODIPY derivatives have been synthesized using the methodology that includes as a key step the condensation of pyrroles with trifluoro(2,3-cycloalkanopyrrol-2-yl)ethanols. The further reaction of dipyrromethanes thus obtained with DDQ followed by complexation with BF3 leads to either benzo[b]-fused (in the case of dipyrromethanes obtained from trifluoro(4,5,6,7-tetrahydroindol-2-yl)ethanol) or cycloheptano[b]-fused saturated or partially saturated BODIPY dyes. The latter exhibit strong red fluorescence (λem = 588–634 nm, Φf = 0.54–0.68), while benzo[b]-fused do not fluoresce at all in either polar or non-polar solvents. The performed quantum-chemical calculations (TD-CAM-B3LYP/SVP) explain the spectroscopic results.
- Hu, Rui,Petrushenko, Konstantin B.,Sagitova, Elena F.,Sobenina, Lyubov N.,Tomilin, Denis N.,Trofimov, Boris A.,Ushakov, Igor A.,Yang, Guoqiang
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Read Online
- Synthesis of β-nitro ketones from geminal bromonitroalkanes and silyl enol ethers by visible light photoredox catalysis
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Various β-nitro ketones, including those bearing a β-tertiary carbon, were prepared from geminal bromonitroalkanes and trimethylsilyl enol ethers of a broad range of ketones by visible light photoredox catalysis, which were then easily converted into β-amino ketones, 1,3-amino alcohols, α,β-unsaturated ketones, β-cyano ketones and γ-nitro ketones.
- Cao, Haoying,Ma, Shanshan,Feng, Yanhong,Guo, Yawen,Jiao, Peng
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supporting information
p. 1780 - 1783
(2022/02/17)
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- Arylboronic Acid-Catalyzed C-Allylation of Unprotected Oximes: Total Synthesis of N-Me-Euphococcine
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O-Unprotected keto-and aldoximes are readily C-allylated with allyl diisopropyl boronate in the presence of arylboronic acid catalysts to yield highly substituted N-α-secondary and tertiary homoallylic hydroxylamines. The method was used in the total synthesis of the trace alkaloid N-Me-Euphococcine.
- Kürti, László,Kattamuri, Padmanabha V.,Siitonen, Juha H.,Yousufuddin, Muhammed
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supporting information
(2020/03/24)
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- Site-specific catalytic activities to facilitate solvent-free aerobic oxidation of cyclohexylamine to cyclohexanone oxime over highly efficient Nb-modified SBA-15 catalysts
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The development of highly active and selective heterogeneous catalysts for efficient oxidation of cyclohexylamine to cyclohexanone oxime is a challenge associated with the highly sensitive nitrogen center of cyclohexylamine. In this work, dispersed Nb oxide supported on SBA-15 catalysts are disclosed to efficiently catalyze the selective oxidation of cyclohexylamine with high conversion (>75%) and selectivity (>84%) to cyclohexanone oxime by O2without any addition of solvent (TOF = 469.8 h?1, based on the molar amount of Nb sites). The role of the active-site structure identity in dictating the site-specific catalytic activities is probed with the help of different reaction and control conditions and multiple spectroscopy methods. Complementary to the experimental results, further poisoning tests (with KSCN or dehydroxylation reagents) and DFT computational studies clearly unveil that the surface exposed active centers toward activation of the reactants are quite different: the surface -OH groups can catch the NH2group from cyclohexylamine by forming a hydrogen bond and lead to a more facile cyclohexylamine oxidation to desired products, while the monomeric or oligomeric Nb sites with a highly distorted structure play a key role in the dissociation of O2molecules beneficial for insertion of active oxygen species into cyclohexylamine. These catalysts exhibit not only satisfactory recyclability for cyclohexylamine oxidation but also efficiently catalyze the aerobic oxidation of a wide range of amines under solvent-free conditions.
- Ding, Wei,Mao, Liqiu,Peng, Haoyu,Yin, Dulin,Zhong, Wenzhou
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p. 3409 - 3422
(2020/06/09)
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- Copper-Catalyzed Radical C-C Bond Cleavage and [4+1] Annulation Cascade of Cycloketone Oxime Esters with Enaminothiones
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Carbon-carbon bond formation is among the most important reactions in organic synthesis. Reconstruction of a carbon-carbon bond through ring-opening C-C bond cleavage of a strained carbocycle usually occurs via a thermodynamically preferable pathway. However, carbon-carbon bond formation through thermodynamically less favorable C-C bond cleavage has seldom been documented. Herein, we disclose an unusual C-C bond cleavage of cycloketone oxime esters for [4+1] annulation. Under anaerobic copper(I) catalysis, cycloketone oxime esters underwent regioselective, thermodynamically less favorable radical C-C bond cleavage followed by annulation with enaminothiones; that is, α-thioxo ketene N,S-acetals efficiently affording 2-cyanoalkyl-aminothiophene derivatives. Cyclobutanone, -pentanone, -hexanone, and -heptanone oxime esters could act as the effective C1 building blocks in the annulation reaction. An iminyl radical mechanism is proposed for the rare C-C bond cleavage/[4+1] annulation cascade.
- He, Yuan,Lou, Jiang,Wu, Kaikai,Wang, Hongmei,Yu, Zhengkun
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supporting information
(2019/02/14)
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- Transition-Metal-Promoted Direct C?H Cyanoalkylation and Cyanoalkoxylation of Internal Alkenes via Radical C?C Bond Cleavage of Cycloketone Oxime Esters
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Transition-metal-catalyzed alkyl-Heck-type cross-coupling of olefinic C?H bonds has been a challenge in the C?H activation area. Herein, we report FeCl3-promoted efficient direct C?H cyanoalkylation of internal alkenes, that is, ketene dithioacetals, with cycloketone oxime esters via radical C?C bond cleavage under the redox-neutral conditions. With CuCl2 as the catalyst under a dioxygen atmosphere direct C?H cyanoalkoxylation of the same internal alkenes was achieved. The cyanoalkylated tetrasubstituted alkene products could be diversely transformed to cyanoalkyl-funtionalized N- and S-heterocyclic compounds. The mechanistic studies have revealed that these C?H cyanoalkylation and cyanoalkoxylation reactions proceed through a radical pathway. (Figure presented.).
- Lou, Jiang,He, Yuan,Li, Yunlong,Yu, Zhengkun
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supporting information
p. 3787 - 3799
(2019/07/10)
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- Preparation of cyclic prodiginines by mutasynthesis in pseudomonas putida kt2440
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Prodiginines are a group of naturally occurring pyrrole alkaloids produced by various microorganisms and known for their broad biological activities. The production of nature-inspired cyclic prodiginines was enabled by combining organic synthesis with a mutasynthesis approach based on the GRAS (generally recognized as safe) certified host strain Pseudomonas putida KT2440. The newly prepared prodiginines exerted antimicrobial effects against relevant alternative biotechnological microbial hosts whereas P. putida itself exhibited remarkable tolerance against all tested prodiginines, thus corroborating the bacterium’s exceptional suitability as a mutasynthesis host for the production of these cytotoxic secondary metabolites. Moreover, the produced cyclic prodiginines proved to be autophagy modulators in human breast cancer cells. One promising cyclic prodiginine derivative stood out, being twice as potent as prodigiosin, the most prominent member of the prodiginine family, and its synthetic derivative obatoclax mesylate.
- Klein, Andreas Sebastian,Brass, Hannah Ursula Clara,Klebl, David Paul,Classen, Thomas,Loeschcke, Anita,Drepper, Thomas,Sievers, Sonja,Jaeger, Karl-Erich,Pietruszka, J?rg
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p. 1545 - 1552
(2018/10/21)
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- Copper-catalyzed synthesis of thiazol-2-yl ethers from oxime acetates and xanthates under redox-neutral conditions
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A novel copper-catalyzed annulation of oxime acetates and xanthates for the synthesis of thiazol-2-yl ethers with remarkable regioselectivity has been developed. Various oxime acetates, whether derived from aryl ketones or alkyl ketones, or natural product cores are suitable for this conversion. Unique dihydrothiazoles were also obtained when both reaction sites were methine. Mechanistic studies indicated that imino copper(iii) intermediates were involved. In addition, this protocol proceeded under redox-neutral conditions and did not require additives or ligands.
- Zhu, Zhongzhi,Tang, Xiaodong,Cen, Jinghe,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 3767 - 3770
(2018/04/17)
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- Construction of tertiary chiral centers by Pd-catalyzed asymmetric allylic alkylation of prochiral enolate equivalents
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Abstract The palladium-catalyzed decarboxylative allylic alkylation of enol carbonates derived from lactams and ketones is described. Employing these substrates with an electronically tuned Pd catalyst system trisubstituted chiral centers are produced. These stereocenters have been previously challenging to achieve using Pd complex/chiral P-N ligand systems.
- Kita, Yusuke,Numajiri, Yoshitaka,Okamoto, Noriko,Stoltz, Brian M.
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supporting information
p. 6349 - 6353
(2015/08/18)
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- Oxidation of primary amines to oximes with molecular oxygen using 1,1-diphenyl-2-picrylhydrazyl and WO3/Al2O3 as catalysts
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The oxidative transformation of primary amines to their corresponding oximes proceeds with high efficiency under molecular oxygen diluted with molecular nitrogen (O2/N2 = 7/93 v/v, 5 MPa) in the presence of the catalysts 1,1-diphenyl-2-picrylhydrazyl (DPPH) and tungusten oxide/alumina (WO3/Al2O3). The method is environmentally benign, because the reaction requires only molecular oxygen as the terminal oxidant and gives water as a side product. Various alicyclic amines and aliphatic amines can be converted to their corresponding oximes in excellent yields. It is noteworthy that the oxidative transformation of primary amines proceeds chemoselectively in the presence of other functional groups. The key step of the present oxidation is a fast electron transfer from the primary amine to DPPH followed by proton transfer to give the α-aminoalkyl radical intermediate, which undergoes reaction with molecular oxygen and hydrogen abstraction to give α-aminoalkyl hydroperoxide. Subsequent reaction of the peroxide with WO3/Al2O3 gives oximes. The aerobic oxidation of secondary amines gives the corresponding nitrones. Aerobic oxidative transformation of cyclohexylamines to cyclohexanone oximes is important as a method for industrial production of ε-caprolactam, a raw material for Nylon 6.
- Suzuki, Ken,Watanabe, Tomonari,Murahashi, Shun-Ichi
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p. 2301 - 2310
(2013/04/24)
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- Selective ammoximation of ketones and aldehydes catalyzed by a trivanadium-substituted polyoxometalate with H2O2 and ammonia
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The ammoximation of different ketones and aldehydes to their corresponding oximes catalyzed by K6[PW9 V3O 40]·4H2O was carried out with hydrogen peroxide and ammonia in isopropanol at room temperature. High yields of oximes were obtained in this catalytic system. This catalytic system was proved to be heterogeneous by the ammoximation activity of removal of catalyst and the elemental analysis of the filtrate after reaction. A possible procedure for the ammoximation catalyzed by K6[PW9V3O40] ·4H2O with H2O2 and NH 3·H2O was proposed. The fresh and used catalysts were characterized by IR and 31P MAS NMR, which revealed the good stability of the catalyst.
- Xue, Xiaoling,Song, Fangyuan,Ma, Baochun,Yu, Yongze,Li, Cheng,Ding, Yong
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- Europium(III) triflate-catalyzed Trofimov synthesis of polyfunctionalized pyrroles
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The synthesis of polyfunctionalized pyrroles by reaction of a ketoxime with dimethyl acetylenedicarboxylate using europium(III) triflate as the catalyst is described. Copyright
- Madabhushi, Sridhar,Vangipuram, Venkata Sairam,Mallu, Kishore Kumar Reddy,Chinthala, Narsaiah,Beeram, China Ramanaiah
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supporting information; body text
p. 1413 - 1416
(2012/07/13)
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- PTERIDINONES AS INHIBITORS OF POLO - LIKE KINASE
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The present invention provides compounds having a structure according to Formula (I) or a salt or solvate thereof, wherein ring A, X, R1, R2, R3, R4, R5 and R6, are defined herein. The invention further provides pharmaceutical compositions including the compounds of the invention and methods of making and using the compounds and compositions of the invention, e.g., in the treatment and prevention of various disorders, such as Parkinson's disease.
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Page/Page column 73
(2011/07/09)
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- Catalytic process for the ammoximation of carbonyl compounds
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The present disclosure pertains to a process for preparing an oxime in which a carbonyl compound is reacted in the liquid phase with NH3 and H2O2 in the presence of a catalyst to form the corresponding oxime, wherein the catalyst comprises a catalytic component selected from the oxides of metals of group 5 and group 6. The use of a niobia catalyst is particularly preferred. The process according to the disclosure is suitable for the manufacture of numerous oximes, in particular cyclohexanone oxime.
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Page/Page column 3
(2011/08/08)
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- Catalytic process for the ammoximation of carbonyl compounds
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The present invention pertains to a process for preparing an oxime in which a carbonyl compound is reacted in the liquid phase with NH3 and H2O2 in the presence of a catalyst to form the corresponding oxime, characterised in that the catalyst comprises a catalytic component selected from the oxides of metals of group 5 and group 6. The use of a niobia catalyst is particularly preferred. The process according to the invention is suitable for the manufacture of numerous oximes, in particular cyclohexasone oxime.
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Page/Page column 4; 5
(2011/09/12)
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- O-acyl derivatives of cyclopentanone and cycloheptanone oximes
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By acylation of cyclopentanone and cycloheptanone oximes with carboxylic acids anhydrides or chlorides new esters were obtained of cyclopentanone and cycloheptanone oximes and their spectral characteristics were investigated.
- Zhukovskaya,Dikusar
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experimental part
p. 180 - 185
(2010/08/19)
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- Aerobic oxidation of primary amines to oximes catalyzed by DPPH and WO 3/Al2O3
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(Chemical Equation Presented) Catalytic teamwork: Aerobic oxidation of primary amines to the corresponding oximes proceeds highly efficiently in the presence of the catalysts 1,1-diphenyl-2-picrylhydrazyl (DPPH) and WO 3/Al2O3 under mild conditions (see scheme). This new method is both selective and environmentally benign.
- Suzuki, Ken,Watanabe, Tomonari,Murahashi, Shun-Ichi
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supporting information; experimental part
p. 2079 - 2081
(2009/02/06)
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- Mercury-catalyzed rearrangement of ketoximes into amides and lactams in acetonitrile
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(Chemical Equation Presented) An acetonitrile solution of mercury(II) chloride has been found to catalyze efficiently the conversion of a diverse range of ketoximes into their corresponding amides/lactams.
- Ramalingan, Chennan,Park, Yong-Tae
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p. 4536 - 4538
(2008/02/04)
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- A simple synthesis of oximes
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The conversion of alicyclic and aliphatic carbonyl compounds as well as aromatic aldehydes into the corresponding oximes (up to quantitative yields) was achieved by simply grinding these reactants, hydroxylamine hydrochloride and sodium hydroxide without solvent. However, this procedure was unsuccessful in the case of aromatic ketones. In this case it was necessary to add silica gel as a catalyst. Springer-Verlag 2006.
- Damljanovic, Ivan,Vukicevic, Mirjana,Vukicevic, Rastko D.
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p. 301 - 305
(2007/10/03)
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- Chlorination of oximes with aqueous H2O2/HCl system: Facile synthesis of gem-chloronitroso- and gem-chloronitroalkanes, gem-chloronitroso- and gem-chloronitrocycloalkanes
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Chlorination of cyclic and linear ketone oximes with aqueous H 2O2/HCl in a two-phase dichloromethane-water system selectively affords gem-chloronitroso compounds in yields of up to 94%. One-pot oxidation of the resulting gem-chloronitroso compounds with peracetic acid, prepared in situ, gives gem-chloronitroalkanes and cycloalkanes in yields of up to 82%. The advantages of the method are that it is facile and environmentally benign and does not require gaseous chlorine. Georg Thieme Verlag Stuttgart.
- Terent'ev, Alexander O.,Krylov, Igor B.,Ogibin, Yuri N.,Nikishin, Gennady I.
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p. 3819 - 3824
(2008/02/09)
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- A new route to lactam precursors from cycloalkanes: Direct production of nitrosocycloalkanes or cycloalkanone oximes by using tert-Butyl nitrite and N-hydroxyphthalimide
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Clean and selective: Nitrosation and oximation of cycloalkanes was achieved by treating them with tBuONO under Ar in the presente presence of a catalytic amount of N-hydroxyphthalimide (see scheme). The novel, clean nitrosation procedure uses halogen-free, relatively mild reaction conditions and results in good product selectivity (almost no organic byproducts) and high recovery of the catalyst.
- Hirabayashi, Tomotaka,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 1120 - 1123
(2007/10/03)
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- Simple, efficient and one-pot method for synthesis of aminomethylene gem-diphosphonic acid derivatives from ketones via Beckmann rearrangement
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A simple, expeditious and convenient synthesis of aminomethylene gem-diphosphonic acid derivatives in one-pot reaction using ketones, hydroxylamine hydrochloride, phosphorus trichloride and water as starting materials in the presence of pyridine via Beckmann rearrangement is described in the modest yields.
- Wu, Mingshu,Chen, Ruyu,Huang, You
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p. 2441 - 2444
(2007/10/03)
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- A convenient one-pot method of converting alcohols into oximes
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The one-pot conversion of primary and secondary alcohols into oximes is reported using chromium trioxide supported on alumina and hydroxylamine hydrochloride under solvent free condition. This oxidation-oxime formation reaction has been applied to a range of aliphatic and benzylic alcohols.
- Kiasat, Ali Reza,Kazemi, Foad,Nourbakhsh, Kazem
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p. 1809 - 1812
(2007/10/03)
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- Selective heterocyclic amidine inhibitors of human inducible nitric oxide synthase
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The potency and selectivity of a series of 5-hetero-2-iminohexahydroazepines were examined as inhibitors of the three human NOS isoforms. The effect of ring substitution of the 5-carbon for a heteroatom is presented. Potencies (IC50's) for these inhibitors are in the low micromolar range for hi-NOS with some examples exhibiting a 500× selectivity versus hec-NOS.
- Moormann, Alan E.,Metz, Sue,Toth, Mihaly V.,Moore, William M.,Jerome, Gina,Kornmeier, Christine,Manning, Pamela,Hansen Jr., Donald W.,Pitzele, Barnett S.,Webber
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p. 2651 - 2653
(2007/10/03)
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- Reduction of conjugated nitroalkenes with zinc borohydride. A mild method for converting monosubstituted nitroalkenes to nitroalkanes and disubstituted ones to oximes
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Mono-β-substituted conjugated nitroalkenes are readily reduced by zinc borohydride in 1,2-dimethoxyethane to the corresponding nitroalkanes, whereas the disubstituted ones furnish the corresponding oximes in excellent yields.
- Ranu,Chakraborty
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p. 5317 - 5322
(2007/10/02)
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- Highly Selective Reduction of Conjugated Nitroalkenes with Zinc Borohydride in DME
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Zinc borohydride in 1,2-dimethoxyethane reduces α-substituted conjugated nitroalkenes to the corresponding oximes and non-α-substituted ones to the corresponding nitroalkanes in excellent yields.
- Ranu, Brindaban C.,Chakraborty, Rupak
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p. 3579 - 3582
(2007/10/02)
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- REACTION D'OXIMATION DES CETONES V. MECANISME ET EFFETS DE STRUCTURE DANS LA REACTION DE DESHYDRATATION ACIDO-CATALYSEE DES CARBINOLAMINES
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The equilibrium constants of formation and the rate constants of dehydratation of carbinolamines resulting from the addition of hydroxylamine to 19 ketones, - 5 aliphatic, 5 aromatic and 9 cyclanic -, have been measured at 25 deg C in water/methanol 60/40 v/v.We show that the acid catalyzed process predominates in the range of pH 6 to 7 for acetophenones or pH 7 to 8.5 for saturated ketones.The rate constants ratios and Hammett ρ constant of the reaction suggest an sp3 (early) transition state.The changes in rate constant are discussed in terms of torsional and non-bonding steric effects.For several hindered ketones, e.g. 3,3,5,5-tetramethylcyclohexanone, we show the existence of a steric hindrance to the approach of the catalyst; in that case the result is a strong decrease of the rate of the dehydratation.
- Lamaty, G.,Roque, J. P.,Natat, A.,Silou, T.
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p. 2667 - 2676
(2007/10/02)
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- Novel Intramolecular Photorearrangement of Nitronate Anions
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The photochemistry of alkanenitronate anions is described.Irradiation of the alkanenitronate anions leads to hydroxamic acids by oxygen photorearrangement via ?-?* triplet excited states.The stoichiometry of reaction, anion structure and selectivity of migration, the nature of the excited state, the quantum yield of reaction, rehybridization on excitation, and the base dependency are discussed.From the results of a detailed structural study of 19 products it was found that this photorearrangement is a highly regio- and stereospecific reaction.
- Yamada, Kazutoshi,Tanaka, Seiji,Naruchi, Kiyoshi,Yamamoto, Makoto
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p. 5283 - 5289
(2007/10/02)
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