- Cobalt-Catalyzed Radical Hydroamination of Alkenes with N-Fluorobenzenesulfonimides
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An efficient and general radical hydroamination of alkenes using Co(salen) as catalyst, N-fluorobenzenesulfonimide (NFSI) and its analogues as both nitrogen source and oxidant was successfully disclosed. A variety of alkenes, including aliphatic alkenes, styrenes, α, β-unsaturated esters, amides, acids, as well as enones, were all compatible to provide desired amination products. Mechanistic experiments suggest that the reaction underwent a metal-hydride-mediated hydrogen atom transfer (HAT) with alkene, followed by a pivotal catalyst controlled SN2-like pathway between in situ generated organocobalt(IV) species and nitrogen-based nucleophiles. Moreover, by virtue of modified chiral cobalt(II)-salen catalyst, an unprecedented asymmetric version was also achieved with good to excellent level of enantiocontrol. This novel asymmetric radical C?N bond construction opens a new door for the challenging asymmetric radical hydrofunctionalization.
- Lv, Guowei,Meng, Qi,Qin, Tao,Xiong, Tao,Zhang, Ge,Zhang, Qian
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supporting information
p. 25949 - 25957
(2021/11/01)
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- Mechanically induced solvent-free esterification method at room temperature
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Herein, we describe two novel strategies for the synthesis of esters, as achieved under high-speed ball-milling (HSBM) conditions at room temperature. In the presence of I2 and KH2PO2, the reactions afford the desired esterification derivatives in 45% to 91% yields within 20 min of grinding. Meanwhile, using KI and P(OEt)3, esterification products can be obtained in 24% to 85% yields after 60 min of grinding. In addition, the I2/KH2PO2 protocol was successfully extended to the late-stage diversification of natural products showing the robustness of this useful approach. Further application of this method in the synthesis of inositol nicotinate was also discussed. This journal is
- Zheng, Lei,Sun, Chen,Xu, Wenhao,Dushkin, Alexandr V.,Polyakov, Nikolay,Su, Weike,Yu, Jingbo
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p. 5080 - 5085
(2021/02/05)
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- Activity and specificity studies of the new thermostable esterase EstDZ2
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In this paper, we study the activity and specificity of EstDZ2, a new thermostable carboxyl esterase of unknown function, which was isolated from a metagenome library from a Russian hot spring. The biocatalytic reaction employing EstDZ2 proved to be an efficient method for the hydrolysis of aryl p-, o- or m-substituted esters of butyric acid and esters of secondary alcohols. Docking studies revealed structural features of the enzyme that led to activity differences among the different substrates.
- Myrtollari, Kamela,Katsoulakis, Nikolaos,Zarafeta, Dimitra,Pavlidis, Ioannis V.,Skretas, Georgios,Smonou, Ioulia
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- Electrochemical Hydrogenation with Gaseous Ammonia
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As a carbon-free and sustainable fuel, ammonia serves as high-energy-density hydrogen-storage material. It is important to develop new reactions able to utilize ammonia as a hydrogen source directly. Herein, we report an electrochemical hydrogenation of alkenes, alkynes, and ketones using ammonia as the hydrogen source and carbon electrodes. A variety of heterocycles and functional groups, including for example sulfide, benzyl, benzyl carbamate, and allyl carbamate were well tolerated. Fast stepwise electron transfer and proton transfer processes were proposed to account for the transformation.
- Li, Jin,He, Lingfeng,Liu, Xu,Cheng, Xu,Li, Guigen
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supporting information
p. 1759 - 1763
(2019/01/16)
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- Hydroxy-Directed Amidation of Carboxylic Acid Esters Using a Tantalum Alkoxide Catalyst
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We describe herein a new strategy for the chemoselective synthesis of amides by using a metal-catalyzed hydroxy-directed reaction. A hydroxy group located at the β-position of an ester group promoted the activation of a carbonyl group with a tantalum alkoxide catalyst followed by amidation reactions, leading to a wide variety of β-hydroxyamides with excellent chemeselectivity. The chemoselective amidation strategy can be extended to the catalytic synthesis of dipeptide derivatives, which remains challenging research subjects in modern organic synthesis.
- Tsuji, Hiroaki,Yamamoto, Hisashi
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supporting information
p. 14218 - 14221
(2016/11/13)
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- The insertion of arynes into the O-H bond of aliphatic carboxylic acids
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The insertion of arynes into the O-H bond of aliphatic carboxylic acids promoted by sodium carboxylates is described. The reactions led to the formation of aryl carboxylates in good yields with good chemoselectivities under mild conditions.
- Wen, Chunxiao,Chen, Qian,He, Zhenwen,Yan, Xinxing,Zhang, Changyuan,Du, Zhiyun,Zhang, Kun
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supporting information
p. 5470 - 5473
(2015/09/15)
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- A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions
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A novel tropylium-based coupling reagent has been developed to facilitate the synthesis of a series of esters, amides, lactones and peptides under mild reaction conditions. Remarkably, this reagent can be used in catalytic amounts in conjunction with a sacrificial reagent, offering a new and efficient method for nucleophilic coupling reactions of carboxylic acids.
- Nguyen, Thanh V.,Lyons, Demelza J.M.
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supporting information
p. 3131 - 3134
(2015/06/17)
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- Intermolecular C-O addition of carboxylic acids to arynes: Synthesis of o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones
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An efficient and simple route to biologically and pharmaceutically important o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones has been developed utilizing readily available carboxylic acids and commercially available o-(trimethylsilyl)aryl tr
- Dubrovskiy, Anton V.,Larock, Richard C.
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p. 2789 - 2798
(2013/03/29)
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- O-acylation of substituted phenols with various alkanoyl chlorides under phase-transfer catalyst conditions
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Esterification of several types of mono-and disubstituted phenols with various mono-and dialkanoyl chlorides was performed in phase-transfer catalysis conditions, using tetrabutylammonium chloride in a mixture of aqueous NaOH and dichloromethane. The process is particularly efficient (almost quantitative yields) as well as rapid (only 5 min reaction time, at a temperature of0°C). Taylor & Francis Group, LLC.
- Simion, Alina Marieta,Hashimoto, Iwao,Mitoma, Yoshiharu,Egashira, Naoyoshi,Simion, Cristian
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experimental part
p. 921 - 931
(2012/02/01)
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- THERAPEUTIC FOR HEPATIC CANCER
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A novel pharmaceutical composition for treating or preventing hepatocellular carcinoma and a method of treatment are provided. A pharmaceutical composition for treating or preventing liver cancer is obtained by combining a chemotherapeutic agent with an anti-glypican 3 antibody. Also disclosed is a pharmaceutical composition for treating or preventing liver cancer which comprises as an active ingredient an anti-glypican 3 antibody for use in combination with a chemotherapeutic agent, or which comprises as an active ingredient a chemotherapeutic agent for use in combination with an anti-glypican 3 antibody. Using the chemotherapeutic agent and the anti-glypican 3 antibody in combination yields better therapeutic effects than using the chemotherapeutic agent alone, and mitigates side effects that arise from liver cancer treatment with the chemotherapeutic agent.
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- Comparisons of O-acylation and Friedel-Crafts acylation of phenols and acyl chlorides and Fries rearrangement of phenyl esters in trifluoromethanesulfonic acid: Effective synthesis of optically active homotyrosines
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Reactions involving phenol derivatives and acyl chlorides have to be controlled for competitive O-acylations and C-acylations (Friedel-Crafts acylations and Fries rearrangements) in acidic condition. The extent for these reactions in trifluoromethanesulfonic acid (TfOH), which is used as catalyst and solvent, is examined. Although diluted TfOH was needed for effective O-acylation, concentrated TfOH was required for effective C-acylations in mild condition. These results have been applied to the novel synthesis of homotyrosine derivatives. Both Fries rearrangement of N-TFA-Asp(OBn)-OMe and Friedel-Crafts acylation of phenol with N-TFA-Asp(Cl)-OMe in TfOH afforded the homotyrosine skeleton, followed by reduction and deprotection afforded homotyrosines maintaining stereochemistry of Asp as an optically pure form.
- Murashige, Ryo,Hayashi, Yuka,Ohmori, Syo,Torii, Ayuko,Aizu, Yoko,Muto, Yasuyuki,Murai, Yuta,Oda, Yuji,Hashimoto, Makoto
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experimental part
p. 641 - 649
(2011/03/19)
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- Intermolecular C-O addition of carboxylic acids to arynes
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(Figure Presented) A novel, efficient, and expedient route to biologically and pharmaceutically important o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones has been developed starting from readily available carboxylic acids and commercially available o-(trimethylsilyl)aryl triflates.
- Dubrovskiy, Anton V.,Larock, Richard C.
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scheme or table
p. 3117 - 3119
(2010/08/22)
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- Anti-Claudin 3 Monoclonal Antibody and Treatment and Diagnosis of Cancer Using the Same
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Monoclonal antibodies that bind specifically to Claudin 3 expressed on cell surface are provided. The antibodies of the present invention are useful for diagnosis of cancers that have enhanced expression of Claudin 3, such as ovarian cancer, prostate cancer, breast cancer, uterine cancer, liver cancer, lung cancer, pancreatic cancer, stomach cancer, bladder cancer, and colon cancer. The present invention provides monoclonal antibodies showing cytotoxic effects against cells of these cancers. Methods for inducing cell injury in Claudin 3-expressing cells and methods for suppressing proliferation of Claudin 3-expressing cells by contacting Claudin 3-expressing cells with a Claudin 3-binding antibody are disclosed. The present application also discloses methods for diagnosis or treatment of cancers.
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- Conjugate reduction of α,β-unsaturated esters and amides with tributyltin hydride in the presence of magnesium bromide diethyl etherate
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We report herein that the conjugate reduction of α,β-unsaturated esters and amides, such as aryl acrylates, pantolactone esters of acrylic acids, diethyl itaconate and N-crotonylcamphorsultam, with tributyltin hydride proceeded in moderate to high yields in the presence of magnesium bromide diethyl etherate. The effect of metal halide enhancing the yields is also described.
- Hirasawa, Satomi,Tajima, Yoshie,Kameda, Yoko,Nagano, Hajime
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p. 10930 - 10938
(2008/02/12)
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- PYRIDAZINONE COMPOUNDS AS CALCILYTICS
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Various calcilytic compounds and pharmaceutical compositions containing these compounds are disclosed. Calcilytic compounds are compounds capable of inhibiting calcium receptor activity. Methods for preparing calcilytic compounds, oral bioavailability of calcilytic compounds, and their use as calcium receptor antagonists are also disclosed.
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Page/Page column 26-27
(2010/11/27)
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- Reaction of alkylcarbonyloxymethyl halides with phenols: reevaluating the influence of steric hindrance
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Evidence is presented that contradicts an earlier finding that, in the absence of steric hindrance, the coupling reaction of alkylcarbonyloxymethyl (ACOM) halides with phenols favors acylated product. A one-step synthesis is used to generate sterically unhindered ACOM iodides, which are then reacted with several phenols to give mainly alkylated phenol.
- Thomas, Joshua D.,Sloan, Kenneth B.
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p. 8785 - 8787
(2007/10/03)
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- An eco-friendly method for the synthesis of aryl and alkyl esters of carboxylic acids using acid activated Indian bentonite
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Esterification of various carboxylic acids with phenol and alcohols has been achieved using acid activated Indian bentonite (AAIB) as catalyst. The catalyst is versatile, and the reaction is found to work well for primary, secondary and tertiary alcohols. The yields are very good under specific reaction conditions.
- Vijayakumar,Iyengar, Pushpa,Nagendrappa, Gopalpur,Prakash, B. S. Jai
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p. 922 - 925
(2007/10/03)
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- Conjugate reduction of aryl acrylates with tributyltin hydride in the presence of magnesium bromide diethyl etherate
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The conjugate reduction of aryl acrylates performed with tributyltin hydride in the presence of magnesium bromide diethyl etherate in dichloromethane gave the corresponding saturated esters in moderate to high yields. The reduction of α-methylene-γ-benzyloxycarboxylic acid esters proceeded syn-selectively, but α-methylene-β-oxycarboxylic acid esters afforded reductive elimination products under the reaction conditions.
- Hirasawa, Satomi,Nagano, Hajime,Kameda, Yoko
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p. 2207 - 2209
(2007/10/03)
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- Methods for therapy of radiation cutaneous syndrome
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Compounds of a histone deacetylase inhibitor. The compounds are capable of simultaneously stimulating epithelium regrowth, inhibiting cutaneous fibroblast proliferation, decreasing collagen deposit, suppressing fibrogenic growth factor and subsiding inflammatory cytokine, and are useful inhibiting the main features of radiation cutaneous syndrome. Results include a decrease in skin swelling, promotion of epithelium healing, and prevention of cutaneous fibrosis, ulceration and necrosis. The present invention provides methods of treating, preventing or ameliorating radiation-induced skin damage by administering a therapeutically effective amount of a histone deacetylase inhibitor.
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- Mapping the substrate selectivity and enantioselectivity of esterases from thermophiles
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To identify potential applications of nineteen esterases from thermophiles, we mapped their substrate selectivity and enantioselectivity using a library of 50 esters. We measured the selectivities colorimetrically using Quick E, which uses pH indicators to detect hydrolysis and a chromogenic reference compound as an internal control. The substrate selectivity mapping revealed one esterase, E018b, with a strong preference for acetyl esters (14- to 25-fold over hexanoate). The enantioselectivity mapping revealed a number of cases of high enantioselectivity. Thirteen of the 19 esterases showed moderate or better enantioselectivity (>19) toward 1-phenethyl butyrate favoring the (R)-enantiomer and two esterases (E008, E013) showed moderate or better enantioselectivity (>20) toward methyl 2-chloropropionate favoring the (S)-enantiomer. Three esterases (E001, E004, E005) showed high (>46) enantioselectivity toward menthyl acetate favoring the (R)-enantiomer. This rapid mapping of the selectivity simplifies the characterization of new enzymes.
- Somers, Neil A.,Kazlauskas, Romas J.
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p. 2991 - 3004
(2007/10/03)
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- O-acylation mechanism of p-substituted phenols with various alkanoyl chlorides under phase transfer catalysis conditions
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The phenolic ester synthesis between equimolecular amounts of phenols and various alkanoyl chlorides in the presence of aqueous sodium hydroxide solution in a two-phase system (20 mL of each 10% NaOH and dicloromethane, respectively) was reinvestigated under PTC conditions (10 mmol of tetrabutyl ammonium chloride, BNC). The esterification was complete within several minutes and the obtained ester was in high purity. For example, phenyl acetate was obtained quantitatively at 0°C in 5 minutes using a stoichiometric amount of BNC. This acylation procedure is technically simple and does not require anhydrous conditions. A bimolecular electrophilic attack of alkanoyl chloride against the ion-pair in the organic phase, which was formed between the quaternary ammonium cation and the phenoxide anion, must be a rate-determining step, because a plot of the logarithm of relative rate constants of various alkanoyl chlorides vs Taft's polar substituents constants (taking into account the steric constants, Es) gave a good linear relationship. We have found a simple, rapid, convenient, easily separating and efficient PTC technique to synthesize phenolic esters.
- Hashimoto, Iwao,Kawaji, Takatoshi,Mitoma, Yoshiharu,Simion, Alina M.,Semion, Cristian,Ishimoto, Keiko,Prakash, G.K. Surya,Olah, George A.,Tashiro, Masashi
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p. 149 - 155
(2007/10/03)
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- L-DOPA ethyl ester salts and uses thereof
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The present invention provides non-hygroscopic, crystalline salts of levodopa ethyl ester (LDEE), wherein the salt is the octanoate salt, the myristate salt, the succinate salt, the succinate dihydrate salt, the fumarate salt or the fumarate dihydrate salt of levodopa ethyl ester. The subject invention also encompasses compositions comprising a levodopa ethyl ester salt and a carrier and processes for making these compositions. In addition, the subject invention concerns pharmaceutical compositions comprising a levodopa ethyl ester salt and a pharmaceutically acceptable carrier, as well as processes for making these pharmaceutical compositions. Furthermore, the subject invention includes methods of treating a subject afflicted with Parkinson's disease, senile dementia, dementia of the Alzheimer's type, a memory disorder, depression, hyperactive syndrome, an affective illness, a neurodegenerative disease, a neurotoxic injury, brain ischemia, a head trauma injury, a spinal trauma injury, schizophrenia, an attention deficit disorder, multiple sclerosis and seizures by the administration of levodopa ethyl ester salts.
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- Methods for therapy of connective tissue disease
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Compounds of a histone deacetylase inhibitor. The compounds are capable of simultaneously modulating cell cycle-related gene expression and inflammatory cytokine production, and are useful as anti-inflammatory agents in connective tissue disease resulting from altered patterns of immunoregulation. The present invention provides methods of treating, preventing or ameliorating connective tissue diseases, which share common features including inflammation of skin, joints and soft tissues as well as altered patterns of immunoregulation, by administering a therapeutically effective amount of a histone deacetylase inhibitor.
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- Hydrogenation of alkenes or alkynes using decaborane in methanol
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Alkenes and alkynes were reduced to corresponding alkanes in methanol using decaborane (B10H14) in the presence of Pd/C as catalyst under nitrogen in high yields. (C) 2000 Elsevier Science Ltd.
- Lee, Seung Hwan,Park, Yong June,Yoon, Cheol Min
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p. 887 - 889
(2007/10/03)
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- Regioselective Acylation of Anisole with Carboxylic Acids over HZSM-5 Catalyst
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Over a HZSM-5 catalyst, the liquid-phase acylation of anisole with carboxylic acid gave the phenyl carboxylic ester at lower temperatures (423 K) 4-acyl anisole was the predominant product.
- Wang, Q. L.,Ma, Yudao,Ji, Xingdong,Yan, Hao,Qiu, Qin
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p. 2307 - 2308
(2007/10/02)
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- The Synthesis of Phenyl Carboxylates from p-Bromophenol and Carboxylic Acid
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The reaction of p-bromophenol with carboxylic acids in the presence of triphenylphosphine and triethylamine proceeded at a high temperature, with the elimination of hydrogen bromide, to give phenyl carboxylates and small amounts of p-bromophenyl carboxylates.
- Hashimoto, Shizunobu,Furukawa, Isao
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p. 2839 - 2840
(2007/10/02)
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- A Novel Synthesis of Phenyl Carboxylates
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The direct synthesis of phenyl carboxylates from phenols and carboxylic acids is reported.The reactions proceeded easily when triphenylphosphine and carbon tetrachloride were used as dehydrating agents in the presence of a tertiary amine at room temperature, thus giving esters in high yields.
- Hashimoto, Shizunobu,Furukawa, Isao
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p. 2227 - 2228
(2007/10/02)
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- 13C-NMR. Spectral Differences between Corresponding Methyl Esters, Phenyl Esters and 2-Substituted Chromones
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The 13C-NMR. spectra of 2-substituted chromones (3) are compared with the data of the analogous methyl and phenyl esters (1 and 2).The chemical shift differences found are most prominent for the C-atoms in β-position to the ester carbonyl and chromone C(2), respectively.These shift differences are discussed in terms of conformational differences between the esters 1 and 2 and the analogous chromones 3.
- Sequin, Urs
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p. 2654 - 2664
(2007/10/02)
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