- A continuous process for glyoxal valorisation using tailored Lewis-acid zeolite catalysts
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The aqueous-phase heterogeneously catalysed isomerisation of bio-oil derived glyoxal is herein introduced as a novel route for the sustainable production of glycolic acid. While commercial ultra-stable Y zeolites displayed only moderate performance, their evaluation enabled us to highlight the crucial role of Lewis acidity in the reaction. Gallium incorporation into these zeolites boosted the glycolic acid yield, although the best catalytic results were obtained over tin-containing MFI-type zeolites, reaching 91% yield of the desired product at full conversion. These materials comprised hydrothermally-synthesised Sn-MFI as well as a novel catalyst obtained by the introduction of tin into silicalite-1 by means of a simpler and more scalable method, i.e. alkaline-assisted metallation. In-depth spectroscopic characterisation of these systems uncovered a substantial similarity of the tin centres obtained by the top-down and bottom-up synthetic approaches. NMR spectroscopic studies gave evidence that the reaction follows a 1,2-hydride shift mechanism solely catalysed by Lewis-acid sites. The Sn-MFI analogue could be reused in 5 cycles without the need for intermediate calcination, did not evidence any tin leaching, and demonstrated suitability for utilisation under continuous-flow operation. The tin-based zeolites exhibited remarkable performance also in alcoholic solvents, leading to the one-pot production of relevant alkyl glycolates.
- Dapsens, Pierre Y.,Mondelli, Cecilia,Kusema, Bright T.,Verel, Rene,Perez-Ramirez, Javier
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Read Online
- Demethylative Alkylation of Methionine Residue by Employing the Sulfonium as the Key Intermediate
-
Methionine (Met) offers a valuable handle to achieve peptide chemical modification owing to its unique thioether functional group. In contrast with cysteine, the site-selective functionalization of the hydrophobic and redox-sensitive thioether motif on peptides is still challenging, and strategies for diversification on the Met residue are rarely disclosed. Herein we report a transition-metal-free and redox-neutral approach for Met diversification with substrate diversity, which could be applied to synthesize cyclic peptides.
- Chan, Albert S. C.,Ge, Yang,Hu, Qi-Long,Li, Jian,Liu, Jia-Tian,Song, Zhendong,Xiong, Xiao-Feng
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supporting information
p. 8543 - 8548
(2021/11/13)
-
- Preparation method of levocetirizine
-
The invention provides a preparation method of levocetirizine. The method comprises the following steps of: the step 1, carrying out a cyclization reaction on (R)-4-chlorodiphenyl methylamine and tris(2-chloroethyl)amine to obtain a compound represented by a formula (I); 2, performing condensation reaction of the compound shown in the formula (I) and 2-ethyl glycolate to obtain a compound shown ina formula (II); and the step 3, converting the compound shown in the formula (II) into levocetirizine. According to the preparation method, (R)-4-chlorodiphenyl methylamine and tris(2-chloroethyl)amine are taken as the initial raw materials, and cyclization reaction, condensation reaction and hydrolysis reaction are carried out so as to obtain levocetirizine. The synthetic route provided by the invention is short, the yield is high, and experimental results show that the yield of the levocetirizine prepared by the method provided by the invention can reach 47%, and the purity can reach 99.7%.
- -
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Paragraph 0021-0022
(2020/04/17)
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- A Reversible Liquid-to-Liquid Organic Hydrogen Carrier System Based on Ethylene Glycol and Ethanol
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Liquid organic hydrogen carriers (LOHCs) are powerful systems for the efficient unloading and loading molecular hydrogen. Herein, a liquid-to-liquid organic hydrogen carrier system based on reversible dehydrogenative coupling of ethylene glycol (EG) with ethanol catalysed by ruthenium pincer complexes is reported. Noticeable advantages of the current LOHC system is that both reactants (hydrogen-rich components) and the produced esters (hydrogen-lean components) are liquids at room temperature, and the dehydrogenation process can be performed under solvent and base-free conditions. Moreover, the hydrogenation reaction proceeds under low hydrogen pressure (5 bar), and the LOHC system has a relatively high theoretical gravimetric hydrogen storage capacity (HSC>5.0 wt %), presenting an attractive hydrogen storage system.
- Zhou, Quan-Quan,Zou, You-Quan,Ben-David, Yehoshoa,Milstein, David
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p. 15487 - 15490
(2020/10/02)
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- Preparation method of glycolic acid or glycolate
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The invention discloses a preparation method of glycolic acid or glycolate. The method comprises the following steps of: formaldehyde and carbon monoxide are introduced into a reactor containing a reaction solution to carry out polymerization reaction, wherein the reaction solution contains an acid catalyst; after the relative molecular mass of a polymer generated by the polymerization reaction reaches 2,000 and above, the polymerization reaction system is cooled to crystallize and precipitate the generated polymer; solid-liquid separation is carried out on the material in the reactor; and excessive water or alcohol is added into the obtained solid phase to carry out a depolymerization reaction to obtain glycolic acid or glycolate. Compared with the prior art, the method disclosed by the invention is good in process stability, low in energy consumption, good in economic practicability and high in product yield, and has a very good application prospect.
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Paragraph 0152-0154
(2020/09/20)
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- Silica-supported HClO4 promotes catalytic solvent- and metal-free O-H insertion reactions with diazo compounds
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Solvent-free O-H insertion reactions in the presence of diazo carbonyl compounds were carried-out in very mild conditions. Unlike the traditional metal-catalysed version, employing rhodium acetate dimer, this method uses eco-friendly silica-supported HClO4 as the catalyst. Only 0.3 mol% of this Br?nsted acid catalyst, that can also be recycled several times, is necessary to guarantee very good yields (up to 97%) in the O-H insertion reactions. Reaction set-up is simple and permitted the preparation of forty-three α-hydroxy and α-alkoxy esters/ketones in just 1 h and at room temperature.
- Gallo, Rafael Douglas C.,Burtoloso, Antonio C. B.
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p. 4547 - 4556
(2018/10/17)
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- Preparation method of chlorophenoxyacetic ester
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The invention provides a preparation method of chlorophenoxyacetic ester, wherein the preparation method comprises the following steps: A) carrying out reaction of glycolic acid and alcohol in tolueneto obtain glycolic ester; B) carrying out reaction of glycolic ester and metal alkoxide to obtain a metal salt of glycolic ester; and C) carrying out reaction of the metal salt of glycolic ester andchlorobenzene to obtain the chlorophenoxyacetic ester. The chlorophenoxyacetic ester is synthesized by condensation of chlorobenzene with the metal salt of glycolic ester, the use of chlorophenol withunpleasant odor is effectively avoided, the production of highly toxic dioxins is eliminated, and the product quality and the operating environment of the production site are greatly improved. Motherliquor containing effective ingredients cannot be produced, so the loss of effective ingredients is effectively avoided and the yield of the product is improved.
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Paragraph 0064; 0065
(2019/01/08)
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- Ru-Catalyzed Transfer Hydrogenation of Nitriles, Aromatics, Olefins, Alkynes and Esters
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This paper reports the preparation of new ruthenium(II) complexes supported by a pyrazole-phosphine ligand and their application to transfer hydrogenation of various substrates. These Ru complexes were found to be efficient catalysts for the reduction of nitriles and olefins. Heterocyclic compounds undergo transfer hydrogenation with good to moderate yields, affording examples of unusual hydrogenation of all-carbon-rings. Internal alkynes with bulky substituents show selective reduction to olefins with the unusual E–selectivity. Esters with strong electron-withdrawing groups can be reduced to the corresponding alcohols, if ethanol is used as the solvent. Possible mechanisms of hydrogenation and olefin isomerization are suggested on the basis of kinetic studies and labelling experiments.
- Alshakova, Iryna D.,Gabidullin, Bulat,Nikonov, Georgii I.
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p. 4860 - 4869
(2018/10/02)
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- ARTIFICIAL METALLOENZYMES CONTAINING NOBLE METAL-PORPHYRINS
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The present invention is drawn to artificial metalloenzymes for use in cyclopropanation reactions, amination and C—H insertion.
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Paragraph 0338
(2018/11/21)
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- Generation and Reactivity of Electron-Rich Carbenes on the Surface of Catalytic Gold Nanoparticles
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The reactive nature of carbenes can be modulated, and ultimately reversed, by receiving additional electron density from a metal. Here, it is shown that Au nanoparticles (NPs) generate an electron-rich carbene on surface after transferring electron density to the carbonyl group of an in situ activated diazoacetate, as assessed by Fourier transformed infrared (FT-IR) spectroscopy, magic angle spinning nuclear magnetic resonance (MAS NMR), and Raman spectroscopy. Density functional theory (DFT) calculations support the observed experimental values and unveil the participation of at least three different Au atoms during carbene stabilization. The surface stabilized carbene shows an extraordinary stability against nucleophiles and reacts with electrophiles to give new products. These findings showcase the ability of catalytic Au NPs to inject electron density in energetically high but symmetrically allowed valence orbitals of sluggish molecules.
- Oliver-Meseguer, Judit,Boronat, Mercedes,Vidal-Moya, Alejandro,Concepción, Patricia,Rivero-Crespo, Miguel ángel,Leyva-Pérez, Antonio,Corma, Avelino
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supporting information
p. 3215 - 3218
(2018/03/13)
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- Investigation of synthetic pathways of carboxylic acid phthalocyanines from glycolic and lactic acids
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We present the study of synthetic pathways to prepare carboxylic acid substituted phthalocyanines from glycolic and lactic acids. Hydroquinone was used as an alternative catalyst for cyclotetramerization reaction of metal free and zinc phthalocyanines, which were characterized by 1H MR spectroscopy, infrared absorption and mass analysis. The photophysical and photochemical properties in dimethyl sulfoxide (DMSO) were analyzed. We verified that the presence of the methyl radical group, that distinguish both structures, diminish the macrocycle aggregation in solution and promote higher quantum yields of fluorescence and for singlet oxygen generation.
- do Nascimento, Francisco B.,Ribeiro, Anderson O.
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p. 106 - 116
(2017/08/07)
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- Preparation method of 2-hydroxy acid ester
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The invention relates to a preparation method of 2-hydroxy acid ester and belongs to the technical field of organic synthesis. According to the preparation method of 2-hydroxy acid ester, 2-hydroxy alkyl cyanogens is taken as a raw material to be added to a reaction solution formed by hydrogen chloride, alcohol and water, and after reaction, 2-hydroxy acid ester is obtained. According to the preparation method of 2-hydroxy acid ester, use of a large amount of nonpolar solvent is not needed, and a target product can be obtained by a one-pot method, thus lowering production cost, improving production efficiency and the purify of the target product, and having energy-saving and environment-friendly effects.
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Paragraph 0031; 0033
(2017/04/11)
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- Heat-insulation reaction system and process for preparing glycolate through oxalate hydrogenation
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The invention relates to a heat-insulation reaction system for preparing glycolate through oxalate hydrogenation, belonging to the technical field of glycolate preparation. The system comprises a circulating gas preheater, a vaporization tower, a reaction gas preheater and a hydrogenation reactor communicated in sequence, wherein an outlet of the hydrogenation reaction is communicated with the reaction gas preheater, and the reaction gas preheater is communicated with the circulating gas preheater. The invention also relates to a process for preparing glycolate by using the heat-insulation reaction system. By using the system and process disclosed by the invention, the exothermic reaction temperature rise can be favorably controlled, side reaction can be inhibited, the activity of a catalyst can be improved, the service life of the catalyst can be prolonged, the problems of low oxalate conversion rate, low selectivity of glycolate serving as a product and the like are solved, and the energy consumption is reduced because heating is realized by virtue of system reaction heat. The heat-insulation reaction system and process for preparing glycolate through oxalate hydrogenation have the advantages that the oxalate conversion rate is high, the selectivity of glycolate serving as the product is high, waste heat of the system can be sufficiently utilized, and the energy consumption and the cost can be reduced.
- -
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Paragraph 0027; 0028; 0029
(2016/10/07)
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- An artificial metalloenzyme with the kinetics of native enzymes
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Natural enzymes contain highly evolved active sites that lead to fast rates and high selectivities. Although artificial metalloenzymes have been developed that catalyze abiological transformations with high stereoselectivity, the activities of these artificial enzymes are much lower than those of natural enzymes. Here, we report a reconstituted artificial metalloenzyme containing an iridium porphyrin that exhibits kinetic parameters similar to those of natural enzymes. In particular, variants of the P450 enzyme CYP119 containing iridium in place of iron catalyze insertions of carbenes into C-H bonds with up to 98% enantiomeric excess, 35,000 turnovers, and 2550 hours-1 turnover frequency. This activity leads to intramolecular carbene insertions into unactivated C-H bonds and intermolecular carbene insertions into C-H bonds. These results lift the restrictions on merging chemical catalysis and biocatalysis to create highly active, productive, and selective metalloenzymes for abiological reactions.
- Dydio,Key,Nazarenko,Rha,Seyedkazemi,Clark,Hartwig
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p. 102 - 106
(2016/10/14)
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- Catalytic behaviour of mesoporous metal phosphates in the gas-phase glycerol transformation
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The catalytic behaviour of mesoporous simple (M = Al, Fe, Co, Mn) and binary (Al/M; M = Fe,V,Ca; molar ratio Al/Fe = 50; Al/V = 2; Al/Ca = 1) metal phosphates, synthesized by an economical gelation method, in the gas-phase glycerol reaction at temperatures between 220 °C and 280 °C, has been investigated. The morphology, textural properties and the acidity by pyridine TPD, of the phosphates were also determined. The activity of the phosphates in the formation of the main reaction product (acrolein) depended not only on their acidity (mainly acid sites of weak-medium strength) but also on the redox sites and morphology exhibited. Thus, the aluminium-vanadium phosphate showed the highest value of yield to acrolein, 62% (equivalent to a productivity of 0.88 gACRgcath) at 280 °C, whereas the amorphous FePO4 and AlPO4 were appreciably more active than the rest of the simple phosphates, exhibiting a high crystalline character. The apparent activation energy values obtained for the acrolein formation ranged between 18 and 91 kJ/mol. Based on the identified products in this study, some possible reactions involved in the glycerol transformation have been suggested.
- Lopez-Pedrajas,Estevez,Navarro,Luna,Bautista
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- Natural preservatives
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In the present invention, provided is a compound, which has good antibacterial effects and is denoted by general formula (I), or a pharmaceutical acceptable salt thereof where R1 is saturated or unsaturated straight chains or branch chains of an alkyl group in general formula (I); R2 is hydrogen, methyl or is selected from a general formula (2); and R3 is hydrogen, saturated or unsaturated straight chains or branch chains of an alkyl group, and X is hydrogen or is selected from a hydroxyl group in general formula (2).COPYRIGHT KIPO 2015
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Paragraph 0052; 0053
(2016/12/26)
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- Synthesis of Cu-Zn-Zr-Al-O catalysts via a citrate complex route modified by different solvents and their dehydrogenation/hydrogenation performance
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The quaternary Cu-Zn-Zr-Al-O catalysts have been prepared by a citrate-complex method using deionized water, ethanol, and ethyl acetate as solvents. The solvents with different polarity and solubility have a prominent influence on the reaction pathway(s) of the synthesis. When using ethanol as solvent to prepare the catalysts, the selectivity and yield to ethyl acetate of 89.5 wt% and 70.6 wt%, respectively, corresponding to 78.9 wt% conversion of ethanol, are achieved. This catalyst also shows good catalytic activity and stability (>120 h at 220 °C) in the conversion of ethanol containing 7 wt% of water. Its remarkable performance is due to the existence of smaller CuO particles and their more uniform dispersion, which is beneficial to form Cu-MxOy (M = Zn, Zr, Al) interfaces. The catalyst showing more strong basic sites associated with the high density of O2- that migrated from the interaction of Cu-MxOy, which is favorable for the dehydrogenative dimerization of ethanol to ethyl acetate; furthermore, the moderate chemisorption and desorption of H2 makes this catalyst more favorable for ethanol dehydrogenation. This catalyst also proves to be effective for a series of ethyl ester hydrogenations (e.g., ethyl acetate and diethyl oxalate), indicating a general promotion of these reactions using ethanol as the solvent to prepare the catalysts.
- Ding, Jian,Chen, Jiangang
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p. 82822 - 82833
(2015/10/19)
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- Synthesis and application of glycolic esters in methanol-gasoline as bifunctional additives
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Summary : To explore new and multifunctional additives for methanol-gasoline, glycolic esters were synthesized and screened as phase stabilizer and saturation vapor pressure depressor. The effect of the esters' structure on the efficiency was discussed. It was found that the stability of the blends depend on the length of the glycolic esters' alkoxy group, and hexyl glycolic and octyl glycolic were found to be the most effective in various gasoline-methanol blends. Additionally, the glycolic esters can depress the saturation vapor pressure of methanol-gasoline effectively as well, and decyl glycolic is the most effective one. With these data, it can be concluded that the glycolic esters have the great potential to be used as bifunctional gasoline-methanol additives.
- Tang, Ying,Cheng, Qitong,Zhang, Jie,Yang, Changchun,Wang, Shanshan,Wang, Xiaoli,Zhao, Zhen
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p. 1109 - 1113
(2015/01/30)
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- Electrophilicity and nucleophilicity of commonly used aldehydes
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The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
- Pratihar, Sanjay
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p. 5781 - 5788
(2014/07/22)
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- Preparation and application of Hydroxyacetic Acid Esters as Methanol-Gasoline additives
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In this paper, hydroxyacetic acid esters (glycolic esters) were synthesized and used as phase stabilizer and saturation vapour pressure depressor of methanol-gasoline. The results show that the stabilities of the blends depend on the length of the glycoli
- Jiang, Xiaoyan,Tang, Ying
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p. 8447 - 8450
(2013/11/06)
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- Bridging racemic lactate esters with stereoselective polylactic acid using commercial lipase catalysis
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A productive and enantioselective hydrolysis of racemic mixtures of lactate esters with commercial Candida rugosa lipase was performed. This step contributes to a novel envisioned route for stereoselective PLA production by combining recent chemocatalytic developments with this biocatalytic contribution, foreseeing two separate l- and d-lactate enantiomer streams. A study of the hydrolysis kinetics identified an unexpected rate determining step at the origin of an unprecedented ester reactivity order.
- Van Wouwe, Pieter,Dusselier, Michiel,Basic, Aurelie,Sels, Bert F.
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supporting information
p. 2817 - 2824
(2013/10/08)
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- Antitumor platinum(II) complexes containing platinum-based moieties of present platinum drugs and furoxan groups as nitric oxide donors: Synthesis, DNA interaction, and cytotoxicity
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Six novel platinum(II) complexes 1-6 bearing different furoxan moieties as nitric oxide (NO) donors have been designed, synthesized, and characterized by elemental analysis and 1H NMR, IR, and ESI-MS spectroscopy. The furoxan groups were introduced to the platinum complexes to release NO, which may take synergic action with the platinum-based moieties on the tumor cells. It was found that all compounds exhibited considerable cytotoxicity against human HCT-116 and SGC-7901 cell lines via DNA binding together with NO-releasing features, especially for compound 3. This finding is in accordance with the previous reports that NO hybrids show higher cytotoxicity against colon cancer cell lines compared with their parent compounds.
- Zhao, Jian,Gou, Shaohua,Sun, Yanyan,Fang, Lei,Wang, Zhimei
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p. 10317 - 10324
(2013/01/15)
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- Synthesis of deuterium and C-13-labelled ethyl glycolate and their subsequent use in the synthesis of labelled analogues of the DNA adduct O 6-carboxymethyl-2′-deoxyguanosine
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The adduct O6-carboxymethyl-2′-deoxyguanosine (O 6CMdG) is of importance as it has been previously linked to high red meat diet in humans, and as yet, a liquid chromatography-mass spectrometry (LC-MS) method has not been developed due to lack of appropriate standards. The synthesis of the deuterated and C-13 analogues required the use of [ 2H2]- and [13C2]ethyl glycolate to label the carboxymethyl moiety of O6CMdG. [2H 2]Ethyl glycolate was synthesised via acid hydrolysis of ethyl diazoacetate using deuterated solvents (59% yield), whilst [13C 2]ethyl glycolate was synthesised from [13C 2]glycine in a three-step procedure (35% yield). The labelled ethyl glycolates were then used to synthesise [2H2]- and [ 13C2]O6CMdG for future use as internal standards in the LC-MS analysis of biological samples.
- Moore, Sharon A.,Shuker, David E. G.
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experimental part
p. 855 - 858
(2012/03/26)
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- Combinatorial synthesis of 3,5-Dimethylene substituted 1,2,4-Triazoles
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Combinatorial cyclizations of imidates and hydrazides with methylene linked R groups, generated from the corresponding nitriles and carboxylic acids, respectively, provided a large library of 3,5-dimethylene substituted 1,2,4- trizoles. 2011 Bentham Science Publishers Ltd.
- Woodard, Scott S.,Jerome, Kevin D.
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experimental part
p. 132 - 137
(2012/04/18)
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- Synthesis and in vitro enzyme hydrolysis of trioxadiaza- and tetraoxadiaza-crown ether-based complexing agents with disposable ester pendant arms
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New disposable ester derivatives of the complexing agents N,N′-bis(carboxymethyl)piperazine, -homopiperazine, -1,7-diaza-15-crown-5 and -1,10-diaza-18-crown-6 were synthesized with a variety of synthetic methods and fully characterized. Hydrolytic properties of the pendant arms were studied under different pH conditions as well as in the presence and absence of porcine liver esterase enzyme and approximate hydrolysis half lives were determined by 1H NMR technique. In vitro studies on pig liver cell homogenates and living thin chicken liver slices proved that the selected double ester 4b can penetrate liver tissues spontaneously, liberate the free complexing agent N,N′-bis(carboxymethyl)-18-ane-N2O4 (ODDA) inside the cells and are potentially capable of removing lead and other toxic metal ions from the liver. Georg Thieme Verlag Stuttgart.
- Ivanyi, Timea,Lazar, Istvan
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p. 3555 - 3564
(2007/10/03)
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- Transition Metal-Catalyzed Cyclopropanation of Alkenes in Water: Catalyst Efficiency and in Situ Generation of the Diazo Reagent
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(Matrix Presented) A cyclopropanation reaction involving ethyl diazoacetate and olefins proceeds with surprisingly high efficiency in aqueous media using| Rn(II) carboxylates. Nishiyama's Ru(II) Py box and Katsuki's Co(II) Salen complexes that allow for highly enantioselective cyclopropanations in organic solvents can also be applied to aqueous cyclopropanations with similar results. In situ generate of ethyl diazoacetate and cyclopropanation also proceeds efficiently. A chemoselective O-H insertion is also possible in water when hydrophobic catalysts and alcohols are used.
- Wurz, Ryan P.,Charette, Andre B.
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p. 4531 - 4533
(2007/10/03)
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- Domino processes as a tool for recovering substandard reactions. Synthesis and use of nitroacetic acid esters and amides
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(equation presented) Elusive nitroacetic acid esters and amides were obtained through a halogen exchange reaction of the corresponding bromoacetic acid derivatives with polymer-supported nitrite anion. The process is flawed by a side product catalyzed deg
- Scardovi, Noemi,Casalini, Andrea,Peri, Francesca,Righi, Paolo
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p. 965 - 968
(2007/10/03)
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- Insertion of carbenes into O-H bonds of alcohols catalysed by platinum complexes
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The addition of diazoesters to alcohols in the presence of a catalytic amount of platinum complexes provides the corresponding O-H insertion products in good to excellent yields.
- Schils, Raphael,Simal, Francois,Demonceau, Albert,Noels, Alfred F.,Eremenko, Igor L.,Sidorov, Aleksei A.,Nefedov, Sergei E.
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p. 7849 - 7852
(2007/10/03)
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- Kinetic resolution of aliphatic oxiranes mediated by in situ formed molydenum(VI) (oxo-diperoxo) hydroxy acid amide / chiral diol complexes
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In situ formed molybdenum(VI) (oxo-diperoxo) hydroxy acid amide / chiral diol complexes mediate the efficient kinetic resolution of simple aliphatic oxiranes.This method furnishes high enantiomeric yields of the residual oxirane.The oxidative cleavage of the oxiranes to carbonyl compounds is a non-stoichiometric reaction in the presence of oxygen. oxiranes / kinetic resolution / chiral molybdenum(VI) (oxo-diperoxo) complexes
- Schurig, Volker,Betschinger, Frank
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p. 555 - 560
(2007/10/02)
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- Synthesis and NMR studies of chiral 4-oxazolidinones and rhodanines
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Sterically hindered N-(o-tolyl) and N-(o-chlorophenyl) substituted 2-thioxo-4-oxazolidinones 1 and-thiazolidinones (rhodanines) 2 forming enantiomers by partial rotation around the C - N bond are synthesized. Their chirality is proven by the presence of diastereotopic protons (or carbon atoms) detected by 1H or 13C NMR (1c, 2c). In the presence of (S)(+)-1-(9-anthryl)-2,2,2-trifluoroethanol as an auxilliary the enantiomers showed 1H shift differences of 0.01 ppm for otherwise isochronous nuclei.
- Dogan,Burgemeister,Icli,Mannschreck
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p. 7157 - 7164
(2007/10/02)
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- Herbicidal 2-(phenoxy or phenylthio)-2-(pyrimidinyloxy or 1,3,5-triazinyloxy)-alkanoic acids
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2-(Phenoxy or phenylthio)-2-(pyrimidinyloxy or 1,3,5-triazinyloxy)alkanoic acid compounds, such as ethyl 2-(2-fluorophenoxy)-2-(4,6-dimethylpyrimidin-2-yl-oxy)acetate, were prepared by the reaction of a phenol or thiophenol compound with a 2-chloro-2-(pyrimidinyloxy or 1,3,5-triazinyloxy)alkanoate ester compound or by the reaction of a pyrimidinol or 1,3,5-triazinol with a 2-bromo-2-(phenoxy or phenylthio)alkanoate ester. These compounds, and, especially, agriculturally acceptable salts, esters, and amides of these compounds, were found to have herbicidal utility.
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-
-
- Reactions with Betaines, XXIII. Reactions of Nitrogen- and Sulphur-Betaines with Reactive Halides
-
Trimethylammonium acetic betain (1) reacts with phenacyl bromide and ethyl bromoacetate, respectively, to give the ester bromides 2 and 7.These can be hydrolyzed with aqueous sodium hydrogencarbonate at 20 deg C to yield besides 1 both C-benzoyl-methanol (3) and the glycolic acid ester 8, respectively.The reaction can also be performed in one step by reacting the betain (1) (with can act as a base) in a double molar ratio with the active halide. - Keywords: Trimethylammonium acetic acid betain; Trimethylammonium acetic acid phenacyl ester bromide; Trimethylammonium acetic acid acetoxy ethyl ester bromide; Phenacyl alcohol; Ethyl glycolate
- Wittmann, Helga,Ziegler, Erich
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p. 103 - 112
(2007/10/02)
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- The decomposition of ethyl diazoacetate over zeolite NaCuX
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The decomposition of ethyl diazoacetate catalyzed by Cu(II)-exchanged zeolite NaX, has been studied.Catalytic activity required at least 25 percent sodium exchange of the zeolite.From 25 percent exchange to higher levels the decomposition rate increased linearly with the copper introduced into the zeolite.With cyclohexane as the solvent, the (ethoxycarbonyl)carbene formed was found to yield dimers, diethyl maleate and diethyl fumarate, and also compounds resulting from reaction with the solvent or with residual water present in the zeolite.Reduction of Cu(II) to Cu(I) increased the activity of the catalysts.The degree of hydration of the zeolite had a large effect on the activity of the catalyst and on the selectivity of the reaction.Complexation of the Cu(II) ions with NH3 or 1,2-propanediamine reduced the activity of the zeolite drastically.Zeolite NaCuX showed no induction time in contrast to several copper salts tested.
- Oudejans, J. C.,Kaminska, J.,Bekkum, H. van
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p. 537 - 541
(2007/10/02)
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- An Improved Electrochemical Preparation of Alkoxytriphenylphosphonium Salts
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Constant current electrolysis of triphenylphosphine in acetonitrile containing an alcohol and benzoic or succinic acid in a one-compartment cell gave better yields of the title compounds than the previously reported controlled potential electrolysis in a divided cell.Constant voltage electrolysis was also found to be effective.The phosphonium salts reacted with carboxylic acids to form esters in high yields.Keywords - alkoxytriphenylphosphonium perchlorates; triphenylphosphine; anodic oxidation; constant current electrolysis; constant voltage electrolysis; ester formation
- Ohmori, Hidenobu,Nakai, Shiro,Miyasaka, Hitoshi,Masui, Masaichiro
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p. 4192 - 4194
(2007/10/02)
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- Deamination via Nitrogen Derivatives of Sulfonic Acids: N-Alkyl-N-nitroso-4-toluenesulfonamides, N-Alkyl-N-nitro-4-toluenesulfonamides, and N-Alkyl-N'-(4-toluenesulfonyloxy)diimide N-Oxides
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The thermal decomposition of several N-alkyl-N-nitroso-4-toluenesulfonamides, N-alkyl-N-nitro-4-toluenesulfonamides, and N-alkyl-N'-(4-toluenesulfonyloxy)diimide N-oxides was undertaken to determine whether the basicity of the negatively charged counterion in deamination reactions was a reaction variable.The nitrososulfonamides decompose following first-order kinetics to give the corresponding esters with retention of configuration.The reaction characteristics are very similar to those of the N-nitrosocarboxamides, and the reaction mechanisms are presumably very similar also.The N-nitrosulfonamides required high temperatures for decomposition, and they gave an anomalous set of products: amide (by denitration) and olefins, but no nitrous oxide or toluenesulfonate esters.The N'-toluenesulfonoxydiimide N-oxides, isomeric to the nitrosulfonamides, proved to be surprisingly stable compounds; they decompose by first-order kinetics to yield the corresponding esters and nitrous oxide.
- White, Emil H.,Lewis, Charles P.,Ribi, Max A.,Ryan, Thomas J.
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p. 552 - 558
(2007/10/02)
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- 2-(Alkoxycarbonylamino)-1-benzimidazolecarboxylic acid esters with hydroxyaliphatic acids and derivatives thereof
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Substituted 2-alkoxycarbonylamino-1-benzimidazoles having the formula: SPC1 Wherein R is a lower alkyl radical, such as --CH3, and A is various organic radicals, hereinafter defined, such as: EQU1 are useful as fungicides and mite ovicides. An exemplary species of the general class is the compound: 2-(methoxycarbonylamino)-1-benzimidazolecarboxylic acid, ester with ethyl glycolate.
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