- Synthesis and characterization of polyethylene terephthalate (PET) precursors and potential degradation products: Toxicity study and application in discovery of novel PETases
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Polyethylene terephthalate (PET) is widely used material and as such became highly enriched in nature. It is generally considered inert and safe plastic, but due to the recent increased efforts to break-down PET using biotechnological approaches, we realized the scarcity of information about structural analysis of possible degradation products and their ecotoxicological assessment. Therefore, in this study, 11 compounds belonging to the group of PET precursors and possible degradation products have been comprehensively characterized. Seven of these compounds including 1-(2-hydroxyethyl)-4-methylterephthalate, ethylene glycol bis(methyl terephthalate), methyl bis(2-hydroxyethyl terephtahalate), 1,4-benzenedicarboxylic acid, 1,4-bis[2-[[4-(methoxycarbonyl)benzoyl]oxy]ethyl] ester and methyl tris(2-hydroxyethyl terephthalate) corresponding to mono-, 1.5-, di-, 2,5- and trimer of PET were synthetized and structurally characterized for the first time. In-silico druglikeness and physico-chemical properties of these compounds were predicted using variety of platforms. No antimicrobial properties were detected even at 1000 μg/mL. Ecotoxicological impact of the compounds against marine bacteria Allivibrio fischeri proved that the 6 out of 11 tested PET-associated compounds may be classified as harmful to aquatic microorganisms, with PET trimer being one of the most toxic. In comparison, most of the compounds were not toxic on human lung fibroblasts (MRC-5) at 200 μg/mL with inhibiting concentration (IC50) values of 30 μg/mL and 50 μg/mL determined for PET dimer and trimer. Only three of these compounds including PET monomer were toxic to nematode Caenorhabditis elegans at high concentration of 500 μg/mL. In terms of the applicative potential, PET dimer can be used as suitable substrate for the screening, identification and characterization of novel PET-depolymerizing enzymes.
- Djapovic, Milica,Milivojevic, Dusan,Ilic-Tomic, Tatjana,Lje?evi?, Marija,Nikolaivits, Efstratios,Topakas, Evangelos,Maslak, Veselin,Nikodinovic-Runic, Jasmina
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-
- Electrochemical esterification via oxidative coupling of aldehydes and alcohols
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An electrolytic method for the direct oxidative coupling of aldehydes with alcohols to produce esters is described. Our method involves anodic oxidation in presence of TBAF as supporting electrolyte in an undivided electrochemical cell equipped with graphite electrodes. This method successfully couples a wide range of alcohols to benzaldehydes with yields ranging from 70 to 90%. The protocol is easy to perform at a constant voltage conditions and offers a sustainable alternative over conventional methods.
- Smeyne, Dylan,Verboom, Katherine,Bryan, Maria,LoBue, James,Shaikh, Abid
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supporting information
(2021/03/26)
-
- Expanding the Tool Kit of Automated Flow Synthesis: Development of In-line Flash Chromatography Purification
-
Recent advancements in in-line extraction and purification technology have enabled complex multistep synthesis in continuous flow reactor systems. However, for the large scope of chemical reactions that yield mixtures of products or residual starting materials, off-line purification is still required to isolate the desired compound. We present the in-line integration of a commercial automated flash chromatography system with a flow reactor for the continuous synthesis and isolation of product(s). A proof-of-principle study was performed to validate the system and test the durability of the column cartridges, performing an automated sequence of 100 runs over 2 days. Three diverse reaction systems that highlight the advantages of flow synthesis were successfully applied with in-line normal- or reversed-phase flash chromatography, continuously isolating products with 97-99% purity. Productivity of up to 9.9 mmol/h was achieved, isolating gram quantities of pure product from a feed of crude reaction mixture. Herein, we describe the development and optimization of the systems and suggest guidelines for selecting reactions well suited to in-line flash chromatography.
- Thomson, Christopher G.,Banks, Colin,Allen, Mark,Barker, Graeme,Coxon, Christopher R.,Lee, Ai-Lan,Vilela, Filipe
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supporting information
p. 14079 - 14094
(2021/07/31)
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- Solvent-free synthesis of symmetric methylene diestersviadirect reaction of aromatic carboxylates with 1,n-dihaloalkanes
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An efficient methodology for the synthesis of symmetrical methylene diesters was developed through direct reaction of various aromatic carboxylates with 1,n-dihaloalkanes under solvent-free conditions. This strategy offers a high product yield, facile work-up and purification, and an environmentally friendly approach to obtain long-chain methylene carboxylate scaffolds with increased diversity.
- Bai, Lin,Ding, Shenglong,Ma, Xiaofang
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p. 28711 - 28715
(2021/09/22)
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- METHODS FOR DEPOLYMERIZING POLYESTERS
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A method for depolymerizing a polyester may comprise heating a polyester at a temperature and for a period of time in the presence of a supported metal-dioxo catalyst, optionally, in the presence of H2, to induce hydrogenolysis of ester groups in the polyester and provide monomers of the polyester.
- -
-
Paragraph 0012; 0058-0059
(2021/10/22)
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- Hydrogen-bond-assisted transition-metal-free catalytic transformation of amides to esters
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The amide C-N cleavage has drawn a broad interest in synthetic chemistry, biological process and pharmaceutical industry. Transition-metal, luxury ligand or excess base were always vital to the transformation. Here, we developed a transition-metal-free hydrogen-bond-assisted esterification of amides with only catalytic amount of base. The proposed crucial role of hydrogen bonding for assisting esterification was supported by control experiments, density functional theory (DFT) calculations and kinetic studies. Besides broad substrate scopes and excellent functional groups tolerance, this base-catalyzed protocol complements the conventional transition-metal-catalyzed esterification of amides and provides a new pathway to catalytic cleavage of amide C-N bonds for organic synthesis and pharmaceutical industry. [Figure not available: see fulltext.]
- Huang, Changyu,Li, Jinpeng,Wang, Jiaquan,Zheng, Qingshu,Li, Zhenhua,Tu, Tao
-
-
- Polyethylene Terephthalate Deconstruction Catalyzed by a Carbon-Supported Single-Site Molybdenum-Dioxo Complex
-
Polyethylene terephthalate (PET) is selectively depolymerized by a carbon-supported single-site molybdenum-dioxo catalyst to terephthalic acid (PTA) and ethylene. The solventless reactions are most efficient under 1 atmosphere of H2. The catalyst exhibits high stability and can be recycled multiple times without loss of activity. Waste beverage bottle PET or a PET + polypropylene (PP) mixture (simulating the bottle + cap) proceeds at 260 °C with complete PET deconstruction and quantitative PTA isolation. Mechanistic studies with a model diester, 1,2-ethanediol dibenzoate, suggest the reaction proceeds by initial retro-hydroalkoxylation/β-C?O scission and subsequent hydrogenolysis of the vinyl benzoate intermediate.
- Gao, Yanshan,Kratish, Yosi,Li, Jiaqi,Liu, Shanfu,Marks, Tobin J.
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supporting information
p. 19857 - 19861
(2020/09/21)
-
- PROCESS FOR PREPARING A POWDERY ORGANIC PEROXIDE FORMULATION
-
Process for preparing a powdery organic peroxide formulation, said process comprises the following steps: a) preparing a reaction mixture comprising: - 40-80 wt% water - 10-25 wt% of an acid chloride or chloroformate, - 1 -4 wt% hydrogen peroxide, - 2-8 wt% alkali metal hydroxide, - 1 -25 wt% of a phlegmatizer selected from the group consisting of ethylene glycol dibenzoate, phenyl benzoate, trimethylol propane tribenzoate, glyceryl tribenzoate, ethylene glycol ditoluate, 1,3-propanediol ditoluate, ethylene glycol 4-tert-butylbenzoate, ethylene glycol monobenzoate monotoluate, 2,3- butanediol dibenzoate, 4-methylphenyl benzoate acid ester, trimethylolpropane dibenzoate, and combinations thereof - 0.002-0.20 wt% of a surfactant, and - 0.25-5.0 wt% of an inert organic solvent, all percentages based on the weight of the reaction mixture, b) heating the reaction mixture at a temperature in the range 5-50°C.
- -
-
Page/Page column 12
(2019/07/13)
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- A Straightforward Conversion of Activated Amides and Haloalkanes into Esters under Transition-Metal-Free Cs 2 CO 3 /DMAP Conditions
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The esterification of activated amides, N -acylsaccharins, under transition-metal-free conditions with good functional group tolerance has been developed, resulting in C-N cleavage leading to efficient synthesis of a variety of esters in moderate to good yields. This work demonstrates that esterification may proceed by using simple N -acylsaccharins, haloalkanes, and Cs 2 CO 3 as oxygen source.
- Chen, Liuqing,Gu, Ying,Jian, Junsheng,Liu, Yueping,Miao, Liqiong,Wang, Zijia,Zeng, Zhuo
-
supporting information
p. 4078 - 4084
(2019/10/28)
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- Fluoride-Catalyzed Esterification of Amides
-
In recent years, it has been demonstrated that amide carbon–nitrogen bonds can be activated and selectively cleaved using transition metal catalysts. However, these methodologies have been restricted to specific amides; a one-to-one relationship exists between the catalytic system and the amides and also uses large amounts of transition-metal catalysts and ligands. Hence, we now report a general strategy for esterification of common amides using fluoride as a catalyst. This method shows high functional group tolerance, and notably it requires only a slight excess of the alcohol nucleophile, which is a rare case in transition-metal-free amide transformations. Moreover, this approach may provide a new understanding for further studies on esterification of amides and is expected to stimulate the development of alternative methods for direct functionalization of amides.
- Wu, Hongxiang,Guo, Weijie,Daniel, Stelck,Li, Yue,Liu, Chao,Zeng, Zhuo
-
p. 3444 - 3447
(2018/02/21)
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- Synthesis of glycol diesters through the depolymerization of polyethylene glycols with carboxylic acids using a proton-exchanged montmorillonite catalyst
-
A convenient and sustainable method for the synthesis of glycol diesters was developed through the depolymerization of polyethylene glycols (PEGs) with carboxylic acids using proton-exchanged montmorillonite as an efficient solid acid catalyst. Several functionalized glycol diesters were obtained in good yields from PEGs and readily available carboxylic acids. Upon reaction completion, the catalyst could be easily separated by filtration and reused with its activity remaining unchanged.
- Maeno, Zen,Midogochi, Kaoru,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro
-
supporting information
p. 832 - 835
(2018/02/06)
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- Catalytic Alkynylation of Cyclic Acetals and Ketals Enabled by Synergistic Gold(I)/Trimethylsilyl Catalysis
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A completely regioselective and challenging gold(I)-catalyzed ring-opening of cyclic 1,3-dioxolanes and dioxanes by trimethylsilyl alkynes to set diol-derived propargyl trimethylsilyl bis-ethers is reported. This unprecedented and not trivial transformation does not operate with the catalytic methodologies recently reported for catalytic alkynylation of acyclic acetals/ketals, and is uniquely enabled by the application of a recently introduced synergistic gold(I)-silicon catalysis concept capable of producing simultaneously catalytic amounts of two key players, a silicon-based Lewis superacid and a nucleophilic gold acetylide.
- Berthet, Mathéo,Songis, Olivier,Taillier, Catherine,Dalla, Vincent
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p. 9916 - 9922
(2017/09/23)
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- Nanosized mesoporous metal–organic framework MIL-101 as a nanocarrier for photoactive hexamolybdenum cluster compounds
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Inclusion compounds of photoluminescent hexamolybdenum cluster complexes in the chromium terephthalate metal-organic framework, MIL-101 (MIL, Matérial Institut Lavoisier) were successfully synthesized in two different ways and characterized by means of powder X-Ray diffraction, chemical analysis and nitrogen sorption. Some important functional properties of hexamolybdenum cluster complexes for biological and medical applications, in particular singlet oxygen generation ability, luminescence properties, cellular uptake behavior and cytotoxicity were studied. It was revealed that the inclusion compounds possessed significant singlet oxygen generation activity. The materials obtained showed a low cytotoxicity, thus allowing them to be used in living cells. Confocal microscopy of human larynx carcinoma (Hep-2) cells incubated with the inclusion compounds showed that MIL-101 performed as a nanocarrier adhering to the external cell membrane surface and releasing the cluster complexes which that penetrated into the cells. Moreover, photoinduced generation of reactive oxygen species (ROS) in Hep-2 cells incubated with inclusion compounds was demonstrated. The cluster supported on MIL-101 was shown to possess in vivo phototoxicity.
- Cheplakova, Anastasia M.,Solovieva, Anastasiya O.,Pozmogova, Tatiana N.,Vorotnikov, Yuri A.,Brylev, Konstantin A.,Vorotnikova, Natalya A.,Vorontsova, Elena V.,Mironov, Yuri V.,Poveshchenko, Alexander F.,Kovalenko, Konstantin A.,Shestopalov, Michael A.
-
p. 100 - 107
(2016/11/18)
-
- A solid acid catalysis of the preparation process of benzoic acid ester plasticizer (by machine translation)
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The present invention discloses a solid acidify catalytic benzoic acid ester plasticizer of the preparation process, the preparation method is: to benzoic acid and alcohol as the raw material, with agent and catalyst in direct reaction to produce benzoic acid ester compound; catalytic system of the invention compared with the sulfuric acid, toluene sulfonic acid and sulfuric acid to sodium has a better catalytic activity, so the catalyst less consumption, in addition, because of the use of the is supported on a solid acid catalyst, after the reaction directly filtering can realize the separation of the catalyst, and the catalyst can be reused, makes the production process more simple, and can be basically prevent the generation of waste water, makes the production process more green environmental protection. (by machine translation)
- -
-
Paragraph 0020; 0021
(2017/07/05)
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- DBU-Based Dicationic Ionic Liquids Promoted Esterification Reaction of Carboxylic Acid with Primary Chloroalkane Under Mild Conditions
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Abstract: A series of DBU-based (DBU = 1, 8-diazabicyclo [5.4.0] undec-7-ene) dicationic ionic liquids with different anions were successfully synthesized by the reaction of DBU and 1, 6-dichlorohexane. Therein, the dicationic ionic liquid 1, 1′-(hexane-1, 6-diyl)bis(1, 8-diazabicyclo [5.4.0]undec-7-enium) dichlorine (IL-1) was successfully employed as an efficient catalyst in esterification reaction of carboxylic acids with primary chloroalkanes under mild conditions without any additional basic reagents. Moreover, the optimum catalyst could be efficiently reused for five times without any significant change on the catalytic effect. The improved protocol is not only efficient, but also green and pollution-free.
- Liu, Yang,Mao, Guijie,Zhao, Hongyan,Song, Jinyi,Han, Huatao,Li, Zhuofei,Chu, Wenyi,Sun, Zhizhong
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p. 2764 - 2771
(2017/09/14)
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- Effective management of polyethers through depolymerization to symmetric and unsymmetric glycol diesters using a proton-exchanged montmorillonite catalyst
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From the standpoint of green sustainable chemistry, it is very important to build a resource recycling system. Herein, an efficient and practical method for catalytic depolymerization of polyethers to glycol diesters was developed using proton-exchanged montmorillonite (H-mont). H-mont uniquely exhibited high catalytic activity for the depolymerization of polyethers with benzoic anhydride to symmetric glycol dibenzoates under mild reaction conditions. Various symmetric and unsymmetric glycol diesters were obtained from the reaction of diverse polyethers with carboxylic acid derivatives. The high catalytic efficiency for this depolymerization of H-mont is interpreted by its character, in which the montmorillonite layers act as an effective two-dimensional macroligand to form the intercalated complex with polyethers. Furthermore, a new protocol for the utilization of waste polyethers in water was developed based on the catalytic and adsorption abilities of H-mont.
- Maeno, Zen,Yamada, Shota,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro
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p. 2612 - 2619
(2017/07/17)
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- A two-benzoic acid preparation method of dihydric alcohol ester plasticizers (by machine translation)
-
A two-benzoic acid dihydric alcohol ester plasticizers of the preparation method, the method to benzoic acid and dihydric alcohol as raw materials, in under the catalytic action, 100 - 250 °C, to carry out the esterification reaction, the reaction 0.5 - 48h. By distilling under reduced pressure, to obtain two-benzoic acid dihydric alcohol ester product. Two-benzoic acid ester is a non-toxic alcohol plasticizer, can replace the phthalic acid ester used for plastic, rubber in the industry field. The method for preparing the product of high yield, product is easy to separate, environment friendly, has very good application prospect. (by machine translation)
- -
-
Paragraph 0016
(2017/06/14)
-
- Preparation method of dicarboxylic dihydric alcohol ester plasticizer
-
A preparation method of dicarboxylic dihydric alcohol ester plasticizer includes the steps of conducting esterification reaction for 0.5-48 h with monobasic acid and dihydric alcohol as the raw materials under the catalysis effect at a temperature of 100-250 DEG C, and conducting reduced pressure distillation to obtain the dicarboxylic dihydric alcohol ester product. Dicarboxylic dihydric alcohol ester is non-toxic plasticizer and can replace phthalic acid ester to be used for the field of plastic industry, rubber industry and the like. The product prepared through the method is high in yield, easy to separate and friendly to the environment and has good application prospects.
- -
-
Paragraph 0016
(2017/06/02)
-
- Chemoselective Radical Dehalogenation and C-C Bond Formation on Aryl Halide Substrates Using Organic Photoredox Catalysts
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Despite the number of methods available for dehalogenation and carbon-carbon bond formation using aryl halides, strategies that provide chemoselectivity for systems bearing multiple carbon-halogen bonds are still needed. Herein, we report the ability to tune the reduction potential of metal-free phenothiazine-based photoredox catalysts and demonstrate the application of these catalysts for chemoselective carbon-halogen bond activation to achieve C-C cross-coupling reactions as well as reductive dehalogenations. This procedure works both for conjugated polyhalides as well as unconjugated substrates. We further illustrate the usefulness of this protocol by intramolecular cyclization of a pyrrole substrate, an advanced building block for a family of natural products known to exhibit biological activity.
- Poelma, Saemi O.,Burnett, G. Leslie,Discekici, Emre H.,Mattson, Kaila M.,Treat, Nicolas J.,Luo, Yingdong,Hudson, Zachary M.,Shankel, Shelby L.,Clark, Paul G.,Kramer, John W.,Hawker, Craig J.,Read De Alaniz, Javier
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p. 7155 - 7160
(2016/08/30)
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- A 1,2-diyl process for preparation of carboxylic acid esters
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The invention discloses a synthetic method of 1, 2-diol dicarboxylic ester. The method comprises the following step: by taking 2,3-dichloro-5, 6-dicyan-1,4-benzoquinone as a dehydrogenation agent, carrying out reaction on cycloacetal and carboxylic acid in a dried organic solvent for 6-48 hours at 20-140 DEG C to obtain 1, 2-diol dicarboxylic ester, wherein the molar ratio of cycloacetal to carboxylic acid is (1-10): 1 and the molar ratio of the dehydrogenation agent to carboxylic acid is (1-10): 1. The method overcomes the defects that in the prior art, a strong acid or an expensive coupling agent is required, monoester needs to be pre-prepared when asymmetrical dicarboxylic ester is synthesized, and 1,2-diol in the process is excessive in amount and the like. The synthetic method has the advantages that 1) by taking 2,3-dichloro-5,6-dicyan-1,4-benzoquinone as the dehydrogenation agent, non-metal coupling is realized, and heavy metal ions are prevented from being left in a product; 2) the reaction product is easy to separate and the dehydrogenation agent is easy to regenerate; 3) the process is simple, the cost is low, the product is good in specificity and environmental-friendly; and 4) the conversion efficiency is high. The synthetic method disclosed by the invention plays an important role in industrial production of 1, 2-diol dicarboxylic ester.
- -
-
Paragraph 0013; 0014; 0015; 0016; 0017
(2016/10/17)
-
- Octahedral molybdenum cluster complexes with aromatic sulfonate ligands
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This article describes the synthesis, structures and systematic study of the spectroscopic and redox properties of a series of octahedral molybdenum metal cluster complexes with aromatic sulfonate ligands (nBu4N)2[{Mo6X8}(OTs)6] and (nBu4N)2[{Mo6X8}(PhSO3)6] (where X- is Cl-, Br- or I-; OTs- is p-toluenesulfonate and PhSO3- is benzenesulfonate). All the complexes demonstrated photoluminescence in the red region and an ability to generate singlet oxygen. Notably, the highest quantum yields (>0.6) and narrowest emission bands were found for complexes with a {Mo6I8}4+ cluster core. Moreover, cyclic voltammetric studies revealed that (nBu4N)2[{Mo6X8}(OTs)6] and (nBu4N)2[{Mo6X8}(PhSO3)6] confer enhanced stability towards electrochemical oxidation relative to corresponding starting complexes (nBu4N)2[{Mo6X8}X6].
- Efremova, Olga A.,Vorotnikov, Yuri A.,Brylev, Konstantin A.,Vorotnikova, Natalya A.,Novozhilov, Igor N.,Kuratieva, Natalia V.,Edeleva, Mariya V.,Benoit, David M.,Kitamura, Noboru,Mironov, Yuri V.,Shestopalov, Michael A.,Sutherland, Andrew J.
-
supporting information
p. 15427 - 15435
(2016/10/13)
-
- An Effective Method for the Construction of Esters Using Cs2CO3 as Oxygen Source
-
An effective method for the construction of esters from acyl chloride and halohydrocarbon using Cs2CO3 as an oxygen source was achieved for the first time. The methodology has a wide scope of substrates and can be scaled up. The study of a preliminary reaction mechanism demonstrated that the O in the products comes from Cs2CO3 and this esterification proceeds through a free radical reaction. It was also found that CO2 can also be used in this esterification reaction as an oxygen source.
- Ren, Lanhui,Wang, Lianyue,Lv, Ying,Li, Guosong,Gao, Shuang
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p. 5172 - 5175
(2015/11/24)
-
- Copper-catalyzed Csp3-O cross-coupling of unactivated alkyl halides with organic peroxides
-
An efficient Cu-catalyzed Csp3-O coupling of peroxides with haloalkanes is described. High yields of products were achieved under mild conditions. Significantly, in addition to primary alkyl halides, secondary alkyl halogenated hydrocarbons could also be applied to this system. The new reaction system could tolerate a wide range of organic peroxides.
- Chen, Huan-Huan,Wang, Guang-Zu,Han, Jin,Xu, Meng-Yu,Zhao, Yong-Qiang,Xu, Hua-Jian
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p. 212 - 217
(2014/01/06)
-
- Nanoscaled inclusion complexes of β-cyclodextrin with binuclear compounds based on diols containing fragments of selected aromatic monocarboxylic acids
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Stable nanoscaled mono- and dimeric inclusion complexes of β-cyclodextrin with hosts based on symmetric diols of various length containing fragments of benzoic, nicotinic, or isonicotinic acid were synthesized.
- Kurochkina,Grachev,Batalova
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p. 753 - 757
(2014/06/09)
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- Facile esterification of carboxylic acid using amide functionalized benzimidazolium dicationic ionic liquids
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Herein, we report the synthesis of a new series of amide functionalized dicationic benzimidazolium based ionic liquids (DBimILs) and appraised their efficacy towards perceptive esterification of carboxylic acids with alkyl/allyl/aryl halides in presence of triethylamine. The amide groups present in this new series of DBimILs are expected to form hydrogen bonding with the carboxylic acids and this could facilitate the esterification reactions under mild conditions devoid of any added catalyst or organic solvent. The plausible mechanism for the enhanced catalytic activity in presence of this new series of ILs has been proposed. The corresponding alkyl/allyl/aryl esters isolated from this reaction were of high purity after simple extraction, which wipe out the necessity for further purification. This protocol addresses clean methodology and the efficient recyclability as well as reusability of the catalyst.
- Muskawar, Prashant Narayan,Thenmozhi,Gajbhiye, Jayant M.,Bhagat, Pundlik Rambhau
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p. 214 - 220
(2014/07/08)
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- Metal-free DDQ-mediated oxidative C-O coupling of acetalic sp3 C-H bonds with carboxylic acids
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A simple and efficient DDQ-mediated oxidative C-O coupling reaction between acetalic sp3 C-H and carboxylic acid O-H bonds has been developed. This novel transformation smoothly proceeds without any metal catalyst and allows for the highly efficient synthesis of (un)symmetric glycol diesters in a single step. This journal is
- Li, Jiang-Sheng,Xue, Yuan,Fu, Dong-Mei,Li, Dao-Lin,Li, Zhi-Wei,Liu, Wei-Dong,Pang, Huai-Lin,Zhang, Yue-Fei,Cao, Zhong,Zhang, Ling
-
p. 54039 - 54042
(2015/02/05)
-
- The first water-soluble hexarhenium cluster complexes with a heterocyclic ligand environment: Synthesis, luminescence, and biological properties
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The hexarhenium cluster complexes with benzotriazolate apical ligands [{Re6(μ3-Q)8}(BTA)6] 4- (Q = S, Se; BTA = benzotriazolate ion) were obtained by the reaction of [{Re6(μ3-Q)8}(OH) 6]4- with molten 1H-BTA (1H-benzotriazole). The clusters were crystallized as potassium salts and characterized by X-ray single-crystal diffraction, elemental analyses, and UV-vis and luminescence spectroscopy. In addition, their cellular uptake and toxicity were evaluated. It was found that both clusters exhibited luminescence with high lifetimes and quantum yield values; they were taken up by the cells illuminating them under UV irradiation and, at the same time, did not exhibit acute cytotoxic effects.
- Shestopalov, Michael A.,Zubareva, Kristina E.,Khripko, Olga P.,Khripko, Yuri I.,Solovieva, Anastasiya O.,Kuratieva, Natalia V.,Mironov, Yuri V.,Kitamura, Noboru,Fedorov, Vladimir E.,Brylev, Konstantin A.
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p. 9006 - 9013
(2014/12/10)
-
- OPTICAL DEVICES
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The invention relates to optical devices; especially intraocular lens made from high refractive index polymers produced from hydroxyalkyl acrylates and methacrylates containing aromatic groups and carbonyl groups. The invention also relates to the starting monomers, the polymers produced; the application of the same for the manufacture of optical devices and the products derived therefrom.
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-
Page/Page column 10-11
(2012/02/05)
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- Odd-even effect of dopant molecules on clearing temperatures of nematic liquid-crystal phases
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Nematic liquid-crystal phases doped with the novel dopant compounds 1 (C6F5COO(CH)nOCOC6F5, n = 17) and 2 (C6H5-COO(CH)nOCOC6H 5, n = 17) showed an "opposite odd-even effect" on clearing temperatures. The tendency was exactly opposite to that reported for liquid-crystal dimers. A mechanism is postulated on the basis of the difference in the formation of molecular aggregations of even- and odd-number-dopant molecules in the host liquid-crystal molecules.
- Kishikawa, Keiki,Haga, Yuri,Inoue, Takahiro,Watanabe, Tomohiro,Takahashi, Masahiro,Kohmoto, Shigeo
-
supporting information
p. 1465 - 1467
(2013/01/16)
-
- Imidazol(in)ium-2-carboxylates as latent, thermally activated organocatalysts for transesterification reactions
-
1,3-Disubstituted imidazol(in)ium-2-carboxylates (ImCO2) were used as precatalysts for transesterification reactions of unactivated ethyl benzoate with monohydric alcohols, dihydric alcohols, and amino alcohols. Highly active N-heterocyclic carbenes (NHCs) are usually not used directly as catalysts because of their air and moisture sensitivity. Here they were liberated in situ by thermal decarboxylation of ImCO2 at designated temperatures. The results showed that the yield of the reactions reached up to 95 within 3 h using only 0.5 mol catalyst. No active enol esters, molecular sieves, or a 20-fold excess of alcohol were used to drive the reaction to completion. It was proved that unsaturated imidazolium-2-carboxylates have a better activity than saturated species in this type of reaction. Different types of substituting groups of ImCO2 exhibited varied transesterification activity.
- Wang, Yanqin,Li, Zhenjiang
-
experimental part
p. 502 - 507
(2012/07/17)
-
- Imidazol(in)ium-2-carboxylates as Latent, Thermally Activated Organocatalysts for Transesterification Reactions
-
1,3-Disubstituted imidazol(in)ium-2-carboxylates (ImCO2) were used as precatalysts for transesterification reactions of unactivated ethyl benzoate with monohydric alcohols, dihydric alcohols, and amino alcohols. Highly active N-heterocyclic carbenes (NHCs) are usually not used directly as catalysts because of their air and moisture sensitivity. Here they were liberated in situ by thermal decarboxylation of ImCO2 at designated temperatures. The results showed that the yield of the reactions reached up to 95% within 3 h using only 0.5 mol% catalyst. No active enol esters, molecular sieves, or a 20-fold excess of alcohol were used to drive the reaction to completion. It was proved that unsaturated imidazolium-2-carboxylates have a better activity than saturated species in this type of reaction. Different types of substituting groups of ImCO2 exhibited varied transesterification activity.
- Wang, Yanqin,Li, Zhenjiang
-
p. 502 - 507
(2016/04/10)
-
- Inclusion compound of β-cyclodextrin with binuclear guests containing residues of some pharmocologically important aromatic monocarboxylic acids
-
Stable monomeric and dimeric inclusion compounds of β-cyclodextrin with binuclear guests containing the residues of some pharmacologically important aromatic monocarboxylic acids were obtained. Pleiades Publishing, Ltd., 2011.
- Grachev,Charaev,Kurochkina,Batalova,Soboleva,Vasyanina,Nifant'ev
-
experimental part
p. 2129 - 2135
(2012/03/12)
-
- Rapid transesterification of aliphatic and aromatic esters using sodium bis(ethylenedioxy)borate-a mild catalyst
-
A simple, selective transesterification of aliphatic and aromatic esters using a mild base sodium bis(ethylenedioxy)borate is described. The transesterification reactions were performed both in microwave and ultrasonication. Aromatic compounds forms diesters of ethylene glycol while aliphatic compounds forms only monoesters. The IR, MS and NMR characterization are given. In this work, an environmentally benign process for the production of biodiesel from oils using heterogeneous catalyst was developed. Mild borate catalyst was adopted for the production of biodiesel. A study for optimizing the reaction conditions such as the reaction time, the reaction condition, the use of co-solvent and the amount of catalyst, was performed.
- Ramasubramanian,Gopi, Sreeraj,Matharasi, D. Priya,Narasimhan
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experimental part
p. 3660 - 3662
(2012/01/30)
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- Molybdenum hexacarbonyl mediated alkoxycarbonylation of aryl halides
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Mo(CO)mediates the alkoxycarbonylation of aryl halides in their reaction with alcohols to afford arenecarboxylic acid esters. The molybdenum carbonyl complexes act as the catalyst and the source with carbon monoxide. The alkoxycarbonylation proceeds with a small excess of carbon monoxide in the form of Mo(CO)and the procedure is simple compared to the conventional method, which uses palladium catalyst under gaseous carbon monoxide. Using this procedure, a variety of carboxylic acid esters were prepared. Georg Thieme Verlag Stuttgart ? New York.
- Ren, Wei,Emi,Yamane, Motoki
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experimental part
p. 2303 - 2309
(2011/09/19)
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- Reduction of diesters of 1,2-diols. Regioselective C-O bond cleavage of the anionic forms
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The electrochemical reduction of benzoate diesters of glycols has been studied in acetonitrile and N,N-dimethylformamide as solvents. The reductions occur in two closely spaced one-electron steps, and it was found that the dianion diradicals decompose by one of two routes, depending on the substituents on the ethylene moiety: cleavage of two benzoates to produce alkene or formation of benzil by way of a postulated cyclic intermediate to produce also the dianion of the diol. These correspond to cleavage of the R-OC(O)Ar bonds and the RO-C(O)Ar bonds, respectively. When the radical formed by the former cleavage is a primary or secondary radical, the reaction is too slow to compete with the latter reaction that produces benzil. However, when that radical is either tertiary or benzylic, the former cleavage reaction is fast and no benzil is detected. The dianions of p-cyano- and p-nitrobenzoate esters are rather stable on the voltammetric time scale. However, the addition of lithium ions results in detectable formation of 4,4′-dicyanobenzil from four different p-cyanobenzoate diesters.
- Macias-Ruvalcaba, Norma A.,Moy, Cheryl L.,Zheng, Zi-Rong,Evans, Dennis H.
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p. 4829 - 4834
(2007/10/03)
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- Kinetics and quantitative structure-activity relationships for pseudomonas sp. Lipase-catalyzed hydrolysis of both monoesters and diesters of ethylene glycol
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The goal of this work is to study kinetics and quantitative structure-activity relationships for steady states of Pseudomonas sp. lipase-catalyzed hydrolysis of both diesters and monoesters of ethylene glycol. Based on the steady-state kinetics of the enzyme-catalyzed hydrolysis of the diesters of ethylene glycol, the diesters and the monoesters react simultaneously as soon as monoester has started to build up in the reaction medium. In other words, the apparent Km values of the diesters are the Km values of the diesters (KmA) plus the Km values of the monoesters (KmB), and all Vmax values are about the same. Moreover, the pH-stat titration curve of the enzyme-catalyzed hydrolysis of the diesters of ethylene glycol is initially hyperbolic, then there is a sharp falloff in the hydrolysis rate. The abrupt stoppage of the reaction (relaxation stage) may be due to the existence of two phases in the reaction medium, that is, the product (ethylene glycol) and the substrates (the diesters of ethylene glycol) are not miscible. Furthermore, quantitative structure-activity relationships for varied acyl groups of mono- and diesters of ethylene glycol are studied. The fact that both pKmA and pK mB values are linearly correlated with the hydrophobicity constant (π) but not with the electronic substituent constants (σ*) indicates that the affinity of these substrates for the enzyme depends only on the hydrophobicitv of substrates. Copyright
- Chiou, Shyh-Ying,Cheng, Yu-Ru,Lu, Chun-Ping,Lin, Yan-Fu,Lin, Long-Yau,Lin, Gialih
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p. 201 - 207
(2007/10/03)
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- Zinc oxide (ZnO) as a new, highly efficient, and reusable catalyst for acylation of alcohols, phenols and amines under solvent free conditions
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Zinc oxide (ZnO) is a highly efficient catalyst for the acylation of a variety of alcohols, phenols and amines with acid chlorides or acid anhydrides under solvent free conditions. Primary, secondary, tertiary, allylic and benzylic alcohols, diols and phenols with electron donating or withdrawing substituents can be easily acylated in good to excellent yield.
- Hosseini Sarvari, Mona,Sharghi, Hashem
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p. 10903 - 10907
(2007/10/03)
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- Personal care products containing high refractive index esters and methods of preparing the same
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The invention includes personal care compositions and methods of preparing these personal care compositions that include incorporation of a polyol polyester that is the reaction product of an aliphatic polyol that does not contain an ether group, and benzoic acid, wherein the resultant polyol polyester has a refractive index at 25° C. of greater than about 1.5. The aliphatic polyol may have two to three carbon atoms. Alternatively, the invention includes personal care compositions and methods of preparing personal care compositions including incorporating a polyol polyester into a personal care formulation. The polyol polyester is represented by formula (I): wherein R is an aliphatic alkyl group that does not contain an ether group and has a refractive index of greater than about 1.5 at 25° C. Also described are methods of preparing personal care compositions comprising a first phase and a second phase, wherein the second phase contains any of the polyol polyesters described above.
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Page/Page column 4
(2008/06/13)
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- PERSONAL CARE PRODUCTS CONTAINING HIGH REFRACTIVE INDEX ESTERS AND METHODS OF PREPARING THE SAME
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The invention includes personal care compositions and methods of preparing these personal care compositions that include incorporation of a polyol polyester that is the reaction product of an aliphatic polyol that does not contain an ether group, and benzoic acid, wherein the resultant polyol polyester has a refractive index at 25° C of greater than about 1.5. The aliphatic polyol may have two to three carbon atoms. Alternatively, the invention includes personal care compositions and methods of preparing personal care compositions including incorporating a polyol polyester into a personal care formulation. The polyol polyester is represented by formula (I): wherein R is an aliphatic alkyl group that does not contain an ether group and has a refractive index of greater than about 1.5 at 25° C. Also described are methods of preparing personal care compositions comprising a first phase and a second phase, wherein the second phase contains any of the polyol polyesters described above.
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Page/Page column 9; 10
(2008/06/13)
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- Acyl iodides in organic synthesis: II. Reactions with acyclic and cyclic ethers
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Reaction of acyl iodides RCOI (R = Me, Ph) was studied with acyclic and cyclic ethers (Et2O, MeCHCH2(O), ClCH2CHCH 2(O), THF, O(CH2CH2)2O, EtOCH 2CH2OH, EtOCH=CH2, PhOEt]. The reaction occurred with the rupture of one or two CO bonds furnishing the corresponding iodides and esters.
- Voronkov,Trukhina,Vlasova
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p. 1579 - 1581
(2007/10/03)
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- Development of new dyeing photoinitiators for free radical polymerization based on the 1H-pyrazolo[3,4-b]quinoxaline skeleton. Part 2
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Several dyes containing a pyrazoloquinoxaline moiety have been synthesized and evaluated as novel photoinitiators for free radical polymerization induced with the argon-ion laser. The kinetic study of photoinitiated polymerization, performed for viscous monomeric formulations with the use of the most effective dye-N-phenylglycine derivative photoinitiating systems has shown unusual kinetic properties. The experimental data show the presence of "Marcus inverted region"-like kinetic behavior. Analysis of possible reasons for this specific feature suggests that one of the processes that may be responsible for such a specific property is the back electron transfer process. Study of photo-initiated polymerization has shown that there is a linear relationship between the rate of polymerization and the square root of the efficiency of singlet oxygen formation. This finding clearly indicates that the electron transfer process between the tested dyes and electron donors occurs via a triplet state. The observed relationship is also in good agreement with the general equation describing the rate of polymerization, which is (among other parameters) a function of the square root of the quantum yield of triplet state formation. In the paper, it is also shown that the structure of the dye has a strong effect on its polymerization photoinitiation ability. The dyes tested were prepared in such a way as to, (i) restrict the rotational freedom of selected parts of the molecule and (ii) increase the quantum yield of the triplet state formation. The latter was achieved by introducing to the molecule a heavy atom (ZCl2, CI) or different heavy atoms (CICl2).
- Kucybala, Zdzislaw,Pyszka, Ilona,Paczkowski, Jerzy
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p. 1559 - 1567
(2007/10/03)
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- A novel one-pot synthesis of esters by exchange reactions between carbonates and anhydrides
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A new method for the synthesis of esters by exchange reaction between anhydrides and carbonates, without any solvent, in the presence of Ti or Sn based catalyst is presented.
- Berti, Corrado,Colonna, Martino,Marianucci, Elisabetta,Sweileh, Bassam,Pilati, Francesco
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p. 917 - 927
(2007/10/03)
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- Azomethine dyes revisited. Photobleaching of azomethine dyes under photoreducing conditions
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This paper presents the results of a study on the bleaching process of azomethine dyes (AMDs) during their irradiation in the presence of an electron donor N-phenylglycine (NPG). The bleaching process and singlet oxygen formation for the dyes under study occurred with very low quantum yields. Experimental results showed that the bleaching of azomethine dyes may be due to both singlet and triplet states. The prominence of the triplet state was suggested by an analysis of double reciprocal plots for bleaching quantum yields and [NPG]. Additional support for this mechanism was given by results from laser flash experiments with a cyclized form of the dye. In these experiments, a transient optical absorption was attributed to a triplet state, and this state was quenched by NPG with a rate constant of 1.2 × 107 M-1 s-1. A similar experiment performed for a branched dye shows a broad, weak transient absorption which may also indicate a small amount of triplet-state formation. Changes in the dye structure affected the rate of photobleaching. The introduction of heavy atoms into a dye molecule only slightly increased the color-loss efficiency. The decrease or restriction of the freedom of the phenyl-group rotation did not increase the rate of the bleaching process. Significant influence of the azomethine dye structure on photobleaching rates was observed only when there was a strong electron withdrawing group in the R2 position. The most significant increase of the bleaching rate was observed when the branching of the dye was limited, especially when the rotation of substituents around the C=N bond was prevented by structural constraints.
- Kucybala, Zdzislaw,Pyszka, Ilona,Marciniak, Bronislaw,Hug, Gordon L.,Paczkowski, Jerzy
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p. 2147 - 2154
(2007/10/03)
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- Efficient photooxygenation of olefins by a C60 derivative bearing an organofluorine tail
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A C60 derivative bearing an organofluorine tail through the dimethylsilyl moiety (1) was proved to be an efficient photosensitizer in C6F6. Photooxygenation of olefins or dienes was accomplished by catalysis of 1 (0.5 - 1.5 mo1%) at room temperature under an oxygen atmosphere.
- Nagashima, Hideo,Hosoda, Koji,Abe, Tomoaki,Iwamatsu, Shoichi,Sonoda, Takaaki
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p. 469 - 470
(2007/10/03)
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- A new convenient method for selective monobenzoylation of diols
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A new facile method for monoacylation of diols has been developed. A variety of cyclic and acyclic diols, in particular 1,2-diols, was selectively monobenzoylated in good yields by their reaction with benzoyl chloride in the presence of a catalytic amount of dimethyltin dichloride and inorganic bases.
- Maki, Toshihide,Iwasaki, Fumiaki,Matsumura, Yoshihiro
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p. 5601 - 5604
(2007/10/03)
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- Synthesis of 9,10-phenanthrenequinones by photocyclization of derivatives of benzoins: Scope and limitation of the methodology
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Symmetric 9,10-phenanthrenequinones with methyl, methoxy, and chloro substituents at the 3 and 6 positions have been synthesized by photocyclization of 4,5-bis-(aryl)-2-phenyl-1,3,2-dioxaboroles and 2,3- diarydioxenes followed by oxidative hydrolysis.
- Togashi, Denisio Masaharu,Nicodem, David Ernest,Marchiori, Roberto,Marchiori, Maria Luisa P. De F. C.
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p. 1051 - 1063
(2007/10/03)
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- Synthesis of symmetrical and unsymmetrical 1,2-Diketones through cathodic intramolecular coupling of diesters
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Electroreduction of diesters [R1COO(CH2)2OCOR2] with Mg electrode has been found to give the corresponding unsymmetrical 1,2-Diketones (R1COCOR2) with excellent yields.
- Kashimura, Shigenori,Murai, Yoshihiro,Washika, Chise,Yoshihara, Daisuke,Kataoka, Yasuki,Murase, Hiroaki,Shono, Tatsuya
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p. 6717 - 6720
(2007/10/03)
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- Singlet oxygen and electron-transfer mechanisms in the dicyanoanthracene-sensitized photooxidation of 2,3-diphenyl-1,4-dioxene
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The 9,10-dicyanoanthracene-sensitized photooxidation of 2,3-diphenyl-1,4-dioxene in CH3CN produces ethylene glycol dibenzoate and small amounts of epoxide. Most of the diester is formed from singlet oxygen via the dioxetane, and only a small amount by electron transfer. The epoxide is a primary electron-transfer product. Various mechanistic possibilites for the electron-transfer are considered.
- Silverman, Scott K.,Foote, Christopher S.
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p. 7672 - 7675
(2007/10/02)
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- PHOTOOXYGENATION OF PTERIDIN-2,4,7-TRIONES
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The pteridin-2,4,7-trione 6,8'-endoperoxides are synthesized and their thermal reactions are examined.The pteridin-2,4,7-triones (1) reacted smoothly with singlet oxygen to yield the pteridin-2,4,7-trione 6,8'-endoperoxides (2-5).On warming the endoperoxide (2a) reverted to the starting pteridin-2,4,7-trione (1a) with liberation of singlet oxygen, which was confirmed by trapping experiment using typical singlet oxygen acceptors (7-12).
- Nishio, Takehiko,Nishiyama, Tadashi,Omote, Yoshimori
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p. 2979 - 2990
(2007/10/02)
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