- Ultrasonic enhancement on the hydrolysis of diethyl 1,2-benzenedicarboxylate
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The ultrasonic enhancement on the hydrolysis of diethyl 1,2-benzenedicarboxylate results from the dissipated heat when the cavitation micro-bubbles were vigorously collapsed. The effective temperature in a solution depends on the nature of the dissolved gas. The relatively broad region that spreads from the interface of the cavitation micro-bubble plays an important role in the sonolytic hydrolysis of esters.
- Yim, Bongbeen,Yoo, Youngeok,Nagata, Yoshio,Maeda, Yasuaki
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Read Online
- Synthesis of New Dialkyl 2,2′-[Carbonyl bis (azanediyl)]dibenzoates via Curtius Rearrangement
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The 2-(alkylcarbonyl)benzoic acids obtained by esterification of phthalic anhydride are converted into azide derivatives: alkyl 2-[(azidocarbonyl)amino]benzoates and to ureas: dialkyl 2,2′-[carbonyl bis (azanediyl)]dibenzoates. These transformations were carried out using classical Curtius rearrangement conditions in the presence of diphenylphosphoryl azide (DPPA) in a basic medium, followed by hydrolysis. Subsequently, a final condensation reaction of these urea derivatives enabled us to obtain, for the first time, the new alkyl derivatives, alkyl 2-[2,4-dioxo-1,2-dihydroquinazolin-3(4 H)-yl]benzoates. All the new compounds obtained in satisfactory yields were characterized by 1H and 13C NMR, and by X-ray crystallographic analysis.
- Yassine, Hasna,Bouali, Jamila,Oumessaoud, Asmaa,Ourhzif, El Mahdi,Hamri, Salha,Hafid, Abderrafia,Khouili, Mostafa,Pujol, Maria Dolors
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p. 1971 - 1979
(2021/01/21)
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- Palladium-Catalyzed Carboxylate-Assisted Ethoxycarboxylation of Aromatic Acids to Synthesize Monoethyl Phthalate Derivatives with Ethyl Bromodifluoroacetate
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A novel and efficient approach for direct carbonation of aromatic acids with ethyl bromodifluoroacetate as the carbonyl source is reported. A broad range of substrates bearing various functional groups were tolerated, leading to monoalkyl phthalate derivatives in moderate to good yields.
- Tao, Na,Wang, Jie,Yuan, Chunchen,Zeng, Runsheng,Zhao, Ying-Sheng
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supporting information
p. 8607 - 8610
(2019/11/03)
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- Automated on-line monitoring of the TiO2-based photocatalytic degradation of dimethyl phthalate and diethyl phthalate
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A fully automated on-line system for monitoring the TiO2-based photocatalytic degradation of dimethyl phthalate (DMP) and diethyl phthalate (DEP) using sequential injection analysis (SIA) coupled to liquid chromatography (LC) with UV detection was proposed. The effects of the type of catalyst (sol-gel, Degussa P25 and Hombikat), the amount of catalyst (0.5, 1.0 and 1.5 g L-1), and the solution pH (4, 7 and 10) were evaluated through a three-level fractional factorial design (FFD) to verify the influence of the factors on the response variable (degradation efficiency, %). As a result of FFD evaluation, the main factor that influences the process is the type of catalyst. Degradation percentages close to 100% under UV-vis radiation were reached using the two commercial TiO2 materials, which present mixed phases (anatase/rutile), Degussa P25 (82%/18%) and Hombikat (76%/24%). 60% degradation was obtained using the laboratory-made pure anatase crystalline TiO2 phase. The pH and amount of catalyst showed minimum significant effect on the degradation efficiencies of DMP and DEP. Greater degradation efficiency was achieved using Degussa P25 at pH 10 with 1.5 g L-1 catalyst dosage. Under these conditions, complete degradation and 92% mineralization were achieved after 300 min of reaction. Additionally, a drastic decrease in the concentration of BOD5 and COD was observed, which results in significant enhancement of their biodegradability obtaining a BOD5/COD index of 0.66 after the photocatalytic treatment. The main intermediate products found were dimethyl 4-hydroxyphthalate, 4-hydroxy-diethyl phthalate, phthalic acid and phthalic anhydride indicating that the photocatalytic degradation pathway involved the hydrolysis reaction of the aliphatic chain and hydroxylation of the aromatic ring, obtaining products with lower toxicity than the initial molecules.
- Salazar-Beltrán, Daniel,Hinojosa-Reyes, Laura,Maya-Alejandro, Fernando,Turnes-Palomino, Gemma,Palomino-Cabello, Carlos,Hernández-Ramírez, Aracely,Guzmán-Mar, Jorge Luis
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p. 863 - 870
(2019/04/17)
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- Practical selective monohydrolysis of bulky symmetric diesters
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The highly efficient selective monohydrolysis reaction we previously reported has been applied to monohydrolysis of several bulkyl symmetric diesters, including diethyl esters, dipropyl esters, and dibutyl esters. A greater proportion of a polar aprotic co-solvent, DMSO, and aqueous KOH appear to help improve the reactivity of bulky diesters compared to the corresponding dimethyl esters. The procedure is mild and practical, yielding the corresponding half-esters in high yields under simple conditions.
- Shi, Jianjun,Niwayama, Satomi
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p. 799 - 802
(2018/02/10)
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- Practical selective monohydrolysis of bulky symmetric diesters: Comparing with sonochemistry
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The conditions of the practical selective monohydrolysis of symmetric diesters we previously reported have been modified and applied to selective monohydrolysis of bulky symmetric diesters. While ultrasound is generally considered effective for two-phase reactions, its effect actually turned out to be rather marginal. Instead, use of a larger proportion of a polar aprotic co-solvent, DMSO, and aqueous KOH helped enhance the reaction rates and improve the yields of the half-esters. The reactions are simple, mild and practical without special devices.
- Shi, Jianjun,Zhao, Tian,Niwayama, Satomi
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p. 6815 - 6820
(2018/10/20)
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- Preparation method of butylphthalide and pharmaceutical intermediate thereof
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The present invention provides a new pharmaceutical intermediate and a method for preparing butylphthalide by using the new pharmaceutical intermediate. According to the method, o-phthalic acid monoester as a raw material and valerate are subjected to ester condensation, o-pentanoylbenzoic acid is prepared through hydrolysis and decarboxylation, and reducing with sodium borohydride and ring closure are performed to obtain the product. According to the present invention, the method has characteristics of inexpensive and easily-available raw material, mild reaction condition, no high-temperaturereaction, no Grignard reaction, production energy consumption reducing, production cost reducing and operation safety improving.
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Paragraph 0023
(2018/11/03)
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- Carboxylation of Aromatic and Aliphatic Bromides and Triflates with CO2 by Dual Visible-Light–Nickel Catalysis
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We report the efficient carboxylation of bromides and triflates with K2CO3 as the source of CO2 in the presence of an organic photocatalyst in combination with a nickel complex under visible light irradiation at room temperature. The reaction is compatible with a variety of functional groups and has been successfully applied to the synthesis and derivatization of biologically active molecules. In particular, the carboxylation of unactivated cyclic alkyl bromides proceeded well with our protocol, thus extending the scope of this transformation. Spectroscopic and spectroelectrochemical investigations indicated the generation of a Ni0 species as a catalytic reactive intermediate.
- Meng, Qing-Yuan,Wang, Shun,K?nig, Burkhard
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supporting information
p. 13426 - 13430
(2017/10/07)
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- Extremely fast gas/liquid reactions in flow microreactors: Carboxylation of short-lived organolithiums
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Carboxylation of short-lived organolithiums bearing electrophilic functional groups such as nitro, cyano, and alkoxycarbonyl groups with CO 2 to give carboxylic acids and active esters was accomplished in a flow microreactor system. The successful reactions indicate that gas/liquid mass transfer and the subsequent chemical reaction with CO2 are extremely fast. Carboxylation of short-lived organolithiums bearing electrophilic functional groups such as nitro, cyano, and alkoxycarbonyl groups with CO 2 to give carboxylic acids and active esters was accomplished in a flow microreactor system. The successful reactions indicate that gas/liquid mass transfer and the subsequent chemical reaction with CO2 are extremely fast (see scheme).
- Nagaki, Aiichiro,Takahashi, Yusuke,Yoshida, Jun-Ichi
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p. 7931 - 7934
(2014/07/07)
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- Photocatalysis in dimethyl carbonate green solvent: Degradation and partial oxidation of phenanthrene on supported TiO2
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Dimethyl carbonate (DMC) is here proposed-for the first time-as a green organic solvent for photocatalytic synthesis. In this work, the photocatalytic partial oxidation of phenanthrene in dimethyl carbonate (DMC) by using anatase TiO2as the photocatalyst is described as paradigmatic example of a green synthetic process starting from polycyclic aromatic hydrocarbons (PAHs). For comparison, the same reaction carried out also in ethanol, 1-propanol or 2-propanol is reported. The use of DMC as the solvent allowed us to achieve 19% and 23% selectivity towards 9-fluorenone and 6H-benzo[c]chromen-6-one, respectively. The proposed approach may represent both a new green synthetic process and an environmentally friendly route to degradation of PAHs. This journal is
- Bellardita,Loddo,Mele,Panzeri,Parrino,Pibiri,Palmisano
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p. 40859 - 40864
(2015/01/08)
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- A facile and efficient protocol for esterification and acetalization in a PEG1000-D(A)IL/toluene thermoregulated catalyst-media combined systems
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A novel efficient and recyclable temperature-dependent biphasic catalyst and reaction media combined system comprised of PEG-1000 linked dicationic acidic ionic liquid and toluene was developed and applied in esterification of aromatic acids and acetalization of aromatic aldehydes with good to excellent yields. This system is characteristic of temperature-dependent reversible biphasic property, simple and facile recyclability, high catalytic activity and extensive substrate and reaction adaptability.
- Wang, Yinglei,Zhi, Huizhen,Luo, Jun
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- Comparison of large-scale routes to manufacture chiral exo-2-norbornyl thiourea
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Two routes aimed at the manufacture of chiral exo-2-norbornyl thiourea (1) on large scale are described. The first approach involves five chemical steps and hinges on a classical resolution via diastereomeric salt formation. The synthesis utilizes amine 2 as the resolution handle. The second approach includes two chemical steps and a chiral chromatography of (±)-1. Despite the larger initial investment necessary to acquire the chiral stationary phase used in the chromatographic approach, the shorter reaction sequence and efficiency of the chromatographic separation make the second route a more attractive option for long-term applications.
- Caille, Seb,Boni, Jerome,Cox, Geoffrey B.,Faul, Margaret M.,Franco, Pilar,Khattabi, Saab,Klingensmith, Liane M.,Larrow, Jay F.,Lee, James K.,Martinelli, Michael J.,Miller, Larry M.,Moniz, George A.,Sakai, Kenichi,Tedrow, Jason S.,Hansen, Karl B.
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body text
p. 133 - 141
(2010/04/29)
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- Ring-opening of cyclic anhydrides using ionic liquids
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Four novel Bronsted acidic ionic liquids with two different acid sites on the imidazolium cations were synthesised and employed as catalysts and solvents for the ring-opening of cyclic anhydrides to synthesise half-esters. The results showed that these novel Bronsted acidic ionic liquids were efficient and recyclable. Good yields, short reaction times and mild reaction conditions were achieved.
- Jiang, Dong,Wang, Yuan Yuan,Xu, Yan Nan,Dai, Li Yi
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experimental part
p. 167 - 169
(2009/10/15)
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- Monitoring of phthalic acid monoesters in river water by solid-phase extraction and GC-MS determination
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An analytical method for monitoring 10 phthalic acid monoesters in river water was investigated by solid-phase extraction, methylation with diazomethane, and GC-MS. Two cartridge-type solid phases packed with octadesyl-coated silica (C18) and styrenedivinyl polymer (PS-2) and one disk-type solid phase made from octadesyl-coated styrene-divinylbenzene polymer (SDB-XD) were investigated in solid-phase extraction. PS-2 gave the highest recoveries of the three solid phases, and recoveries of more than 80% of the monoesters in filtered water samples were obtained at pH 2 to 3 with PS-2 at the spiked level of 0.1 μg L-1, except for monomethyl-phthalate (MMP), in which more than 72% of the monoesters were recovered. For the monoesters in the suspended solids (SS), an acidic methanol extract of SS was added to purified water acidified to pH 2, and the monoesters were extracted with PS-2. The recoveries of the monoesters in SS were more than 80%, but the recoveries of MMP were more than 57%. The method detection limit (MDL) of each phthalic acid monoester in 500 mL of water sample and in 2 mg of dry weight of SS ranged from 0.010 to 0.030 μg L-1 and from 1 to 11 μg g-1 respectively. Monitoring of phthalic acid monoesters in the Tama River in Tokyo was conducted every month from March 1999 to February 2000 using the present method. MMP, mono-n-butyl-phthalate (MBP), and mono-(2-ethylhexyl)-phthalate (MEHP) were detected at concentrations of 0.030-0.0340, 0.010-0.480, and 0.010-1.30 μg L-1. respectively, in the filtered water samples but were not detected in SS. Dimethyl-phthalate (DMP), di-n-butyl-phthalate (DBP), and di-(2-ethylhexyl)-phthalate (DEHP) were detected in the river water at concentrations of 0.010-0.092, 0.008-0.540, and 0.013-3.60 μg L-1, respectively. Diethyl-, di-iso-butyl-, and benzylbutyl-phthalates were also detected at concentrations of nanograms per liter, whereas the corresponding monoesters did not appear. The concentrations of MBP and MEHP in the river water were slightly lower than those of the corresponding diesters at the majority of sampling sites and sampling times.
- Suzuki,Yaguchi,Suzuki,Suga
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p. 3757 - 3763
(2007/10/03)
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- Ring opening of cyclic anhydrides: Synthesis of achiral half-esters using Lewis acids
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A rapid and high yield preparation of half-esters from cyclic anhydrides using alcohols and Lewis acids is described.
- Sabitha, Gowravaram,Srividya,Yadav
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p. 4015 - 4018
(2007/10/03)
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- Involvement of a novel mouse hepatic microsomal esterase, ES46.5K, in the hydrolysis of phthalate esters
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ES46.5K, a novel esterase from mouse hepatic microsomes (Watanabe K., et al., Biochem. Mol. Biol. Int., 31, 25-30 (1993)), catalyzed hydrolysis of phthalate esters. ES46.5K and mouse hepatic microsomes hydrolyzed diethyl-, dibutyl-, diisobutyl-, dioctyl- and diethylhexyl phthalates, whereas dicyclohexyl- and dipbenyl phthalates having ring structure were not hydrolyzed by the enzymes. V(max) (μmol/min/mg protein)/K(m) (μM) ratios of ES46.5K for diethyl-, dibutyl-, diisobutyl-, dioctyl- and diethylhexyl phthalates were 291, 2786, 565, 51 and 57, respectively, while those of microsomes were 0.58, 0.83, 1.71, 0.05 and 1.10, respectively. The hydrolytic activity of ES46.5K was inhibited by diisopropylfluorophosphate and bis-p- nitrophenylphosphate. These results suggest that ES46.5K has high catalytic activity for phthalate esters and some role in the metabolism of phthalate esters in mice.
- Kayano, Yuichiro,Watanabe, Kazuhito,Matsunaga, Tamihide,Yamamoto, Ikuo,Yoshimura, Hidetoshi
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p. 749 - 751
(2007/10/03)
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- NOUVEAUX DECONTAMINANTS. ACTION DES PERACIDES A GROUPE ESTER SUR QUELQUES TOXIQUES INSECTICIDES OU DE GUERRE
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A new peroxyacid-ester series has been obtained and used in the destruction of toxic agents.These structures oROCOC6H4CO3H and ROCO(CH2)nCO3H are more stable than the unsubstituted compounds.The reaction with paraoxon (O,O-diethyl O-paranitrophenylphosphate) and HD (2,2'-dichlorodiethylsulfide) goes to completion in a very short time.The influence of the R group and the length of the chain (n=2......12) has been studied.The addition of some long chain tetraalkyl-ammonium salts enhances the rate of the reaction by micellar catalysis.
- Lion, C.,Hedayatullah, M.,Bauer, P.,Boukou-Poba, J. P.,Charvy, C.,et al.
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p. 555 - 560
(2007/10/02)
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- RATIO OF LYATE IONS ACTIVITIES IN TWO-COMPONENTS PROTOGENIC SOLVENTS
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Kinetic method for the evaluation of lyate ions activities in two-component protogenic solvents has been discussed.Spectral methods for the measurement of equilibria between alkoxide and hydroxide ions have been compared.A correlation between dissociation constants of water and of weak organic acids in solvent mixtures has been found.By means of this correlation, ratios of lyate ions activities in water-ethanol and water-propanol mixtures have been calculated.These activity ratios, together with the known composition of reaction products, have been used to evaluate the selectivity of the neutral and alkaline solvolysis of phthalic anhydride and benzyl chloride in solvent mixtures quoted above.
- Mollin, Jiri,Pavelek, Zdenek,Kasparek, Frantisek
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p. 1115 - 1130
(2007/10/02)
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- Pd(0)-Catalyzed Electroreductive Cleavage of Allylic Acetates1
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Pd(0)-catalyzed electroreductive cleavage of allylic acetates yielding alkenes and/or allyltrimethylsilanes is described.Deprotection of allyl esters can be performed in the same electrolysis system.
- Torii, Sigeru,Tanaka, Hideo,Katoh, Tetsuo,Morisaki, Kazuo
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p. 3207 - 3208
(2007/10/02)
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