3913-65-3Relevant academic research and scientific papers
Oxidation of threonine by the analytical reagent diperiodatocuprate(III) - An autocatalysed reaction
Jose, Timy P.,Tuwar, Suresh M.
, p. 137 - 144 (2007)
The kinetics of Cu(II) autocatalysed oxidation of threonine by well-recognized analytical reagent diperiodatocuprate(III) in aqueous alkaline medium at a constant ionic strength of 0.5 mol dm-3 was studied spectrophotometrically. The reaction between diperiodatocuprate(III) and threonine in alkaline medium exhibits 2:1 stoichiometry (DPC: threonine). The reaction is of first order in each [DPC] and [threonine] and less than unit order in [alkali]. Periodate has retarding effect on the rate of reaction. Ionic strength has negligible effect on the reaction. Increase in dielectric constant of the medium with decrease in the rate of the reaction was observed. The product, Cu(II), catalyses the reaction with a fractional order. The main products were identified by spot test and I.R. A composite mechanism involving the monoperiodatocuptrate(III) (MPC) as the reactive species of the oxidant in uncatalysed and autocatalysed reaction has been proposed. Activation parameters and the reaction constants involved in the different steps of the mechanisms are calculated.
In-situ IR Spectroscopy Study of Reactions of C3 Oxygenates on Heteroatom (Sn, Mo, and W) doped BEA Zeolites and the Effect of Co-adsorbed Water
Najmi, Sean,So, Jungseob,Stavitski, Eli,McDermott, William P.,Lyu, Yimeng,Burt, Sam P.,Hermans, Ive,Sholl, David S.,Sievers, Carsten
, p. 445 - 458 (2020/12/01)
The reactions of acetone and hydroxyacetone over heteroatom doped BEA zeolites (Sn, Mo, and W) in the presence and absence of H2O vapor are investigated using infrared spectroscopy. Acetone is converted to mesityl oxide over Sn-BEA exclusively. At higher temperatures, larger oxygenates such as phorones, aromatics, and coke form. The presence of co-adsorbed water in Sn-BEA suppresses tautomerization. H2O vapor is also beneficial for minimizing coke formation at high temperatures. Hydroxyacetone is converted into 2-hydroxypropanal over Sn-BEA, exhibiting high affinity to Sn sites up to 400 °C. Sn-BEA catalyzes conversion of hydroxyacetone into the enol in the absence of H2O, but exposure to H2O induces the formation of 2-hydroxypropanal and subsequent conversion to acrolein. The Lewis acid descriptors are used to rationalize the reaction pathways. For the isomerization of hydroxyacetone into 2-hydroxypropanal, the hardness of acid sites influences the reaction and correlates with the overall Lewis acidity of the catalysts, respectively. However, the size of the exchanged metal significantly affects aldol condensation, where keto and enol forms of acetone adsorb to active sites simultaneously.
Method for preparing monoisopropanolamine
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Paragraph 0065; 0074-0075; 0090; 0094-0095, (2021/01/04)
The invention discloses a method for preparing monoisopropanolamine. The method comprises the steps of (a) reacting 1,2-propylene glycol under the action of a dehydrogenation catalyst to obtain 2-hydroxy propionaldehyde; and (b) reacting the 2-hydroxy propionaldehyde obtained in the step (1) with liquid ammonia and hydrogen under the action of a hydrogenation catalyst to prepare monoisopropanolamine. The dehydrogenation catalyst is prepared from a modified gamma-Al2O3 carrier and active components of CuO, PdO, Bi2O3 and In2O3. The hydrogenation catalyst comprises a modified gamma-Al2O3 carrierand active components NiO, V2O5 and Y2O3. Different catalysts and two-step reaction processes are adopted, and the reaction processes of dehydrogenation, imidization and hydrogenation of 1,2-propanediol are controlled to inhibit the generation of by-products such as hydroxyacetone in the dehydrogenation process and by-products such as secondary amine in the amination process, thereby greatly enhancing the yield and selectivity of the monoisopropyl alcohol product.
Continuous catalytic process for the selective dehydration of glycerol over Cu-based mixed oxide
Concepción, Patricia,Domine, Marcelo E.,Mazarío, Jaime,Ventura, María
, p. 160 - 175 (2020/04/08)
The selective dehydration of glycerol to hydroxyacetone (acetol) was studied with Cu-based mixed oxides derived from hydrotalcite as catalysts in a continuous flow fix-bed reactor. Catalysts were prepared by co-precipitation and characterized by ICP, N2 adsorption, XRD, NH3-TPD, CO2-TPD, TPR and TEM. Different parameters were investigated to develop the most appropriate material as well as to determine the function of every metallic species. The optimized Cu-Mg-AlOx offered ≈60% acetol selectivity at >90% glycerol conversion (≈80% liquid yield, up to TOS = 9 h). The catalyst could be regenerated by calcination, achieving full activity recovery after five re-cycles. “In-situ” FTIR and XPS measurements evidenced that the presence of Cu, specially the most active Cu1+ species, was essential to carry out the dehydration to acetol with high reaction rates, and to form the preferred intermediate (with C[dbnd]O group); although a minor contribution from Cu0 and Cu2+ species could not be discarded.
Characterization of methylated azopyridine as a potential electron transfer mediator for electroenzymatic systems
Tetianec, Lidija,Chaleckaja, Ana,Kulys, Juozas,Janciene, Regina,Marcinkeviciene, Liucija,Meskiene, Rita,Stankeviciute, Jonita,Meskys, Rolandas
, p. 41 - 48 (2017/06/05)
N,N'-dimethyl-4,4'-azopyridinium methyl sulfate (MAZP) was characterized as an electron transfer mediator for oxidation reactions catalyzed by NAD+- and pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenases. The bimolecular rate constant of NADH reactivity with MAZP was defined as (2.2?±?0.1)?×?105?M?1?s?1, whereas the bimolecular rate constant of reactivity of the reduced form of PQQ-dependent alcohol dehydrogenase with MAZP was determined to be (4.7?±?0.1)?×?104?M?1?s?1. The use of MAZP for the regeneration of the cofactors was investigated by applying the electrochemical oxidation of the mediator. The total turnover numbers of mediator MAZP and cofactor NADH for ethanol oxidation catalyzed by NAD+-dependent alcohol dehydrogenase depended on the concentration of the substrate and the duration of the electrolysis, and the yield of the reaction was limited by the enzyme inactivation and the electrochemical process. The PQQ-dependent alcohol dehydrogenase was more stable, and the turnover number of the enzyme reached a value of 2.3?×?103. In addition, oxidation of 1,2-propanediol catalyzed by the PQQ-dependent alcohol dehydrogenase proceeded enantioselectively to yield L-lactic acid.
METHOD FOR PRODUCING ALDEHYDE
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Paragraph 0016; 0017-0018, (2017/05/27)
PROBLEM TO BE SOLVED: To provide a new method for producing aldehyde capable of evading reduction under low temperature conditions and having higher selectivity. SOLUTION: Provided is a method for producing aldehyde where activated ester is prepared from carboxylic acid such as saturated fatty acid, unsaturated fatty acid, hydroxy acid, aromatic carboxylic acid and amino acid and an activation ester agent such as halogenated carbonic acid aryl, a carbodiimide-based condensation agent, an imidazole-based condensation agent and a triazine-based condensation agent, and the activated ester is reduced, and being a method for producing aldehyde in which an environmental load is reduce, and having high yield and high selectivity. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
Syntheses and biological evaluation of 1,2,3-triazole and 1,3,4-oxadiazole derivatives of imatinib
Li, Yong-Tao,Wang, Jing-Han,Pan, Cheng-Wen,Meng, Fan-Fei,Chu, Xiao-Qian,Ding, Ya-Hui,Qu, Wen-Zheng,Li, Hui-Ying,Yang, Cheng,Zhang, Quan,Bai, Cui-Gai,Chen, Yue
, p. 1419 - 1427 (2016/02/19)
Three novel series of 1,2,3-triazole and 1,3,4-oxadiazole derivatives of imatinib were prepared and evaluated in vitro for their cytostatic effects against a human chronic myeloid leukemia (K562), acute myeloid leukemia (HL60), and human leukemia stem-like cell line (KG1a). The structure-activity relationship was analyzed by determining the inhibitory rate of each imatinib analog. Benzene and piperazine rings were necessary groups in these compounds for maintaining inhibitory activities against the K562 and HL60 cell lines. Introducing a trifluoromethyl group significantly enhanced the potency of the compounds against these two cell lines. Surprisingly, some compounds showed significant inhibitory activities against KG1a cells without inhibiting common leukemia cell lines (K562 and HL60). These findings suggest that these compounds are able to inhibit leukemia stem-like cells.
Novel urushiols with human immunodeficiency virus type 1 reverse transcriptase inhibitory activity from the leaves of Rhus verniciflua
Kadokura, Kazunari,Suruga, Kohei,Tomita, Tsuyoshi,Hiruma, Wataru,Yamada, Motoyuki,Kobayashi, Akio,Takatsuki, Akira,Nishio, Toshiyuki,Oku, Tadatake,Sekino, Yoshihiro
, p. 148 - 153 (2015/02/19)
Two novel urushiols, 1 and 2, and two known urushiols, 3 and 4, were isolated from the leaves of Rhus verniciflua and were examined for their human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) inhibitory activity. The novel urushiols were found to be 1,2-dihydroxyphenyl-3-[7(E),9(Z),11(Z)-pentadecatrienyl]-14-ol (1) and 1,2-dihydroxyphenyl-3-[8(Z),10(E),12(E)-pentadecatrienyl]-14-ol (2) by spectroscopic analyses. The absolute configuration at C-14 in 1 and 2 was determined to be a racemic mixture of (R) and (S) isomers by ozonolysis. Compound 2 (IC50: 12.6 μM) showed the highest HIV-1 RT inhibitory activity among the four urushiols, being 2.5-fold more potent than the positive control, adriamycin (IC50: 31.9 μM). Although the known urushiols were isolated from the sap and leaves of R. verniciflua, 1 was exclusively present in the leaves, and higher amounts of 2 were found in the leaves than in the sap. Present findings indicate that the leaves of R. verniciflua represent a new biological resource from which novel and known urushiols may be prepared, and the possible use of novel urushiols as bioactive products.
Kinetics and mechanism of the oxidation of diols by butyltriphenylphosphonium dichromate
Panday, Dinesh,Kothari, Seema
experimental part, p. 918 - 925 (2011/09/19)
The oxidation of four vicinal, four non-vicinal diols and one of their monoethers by butyltriphenylphosphonium dichromate (BTPPD), in dimethylsulfoxide (DMSO), resulted in the formation of corresponding hydroxyaldehyde as a main product of the oxidation. The reactions are of first order with respect to BTPPD, however, second order dependence is obtained with respect to each the diol and hydrogen ion. The oxidation of [1,1,2,2-2H 4]ethanediol exhibited primary kinetic isotope effect (k H/kD = 6.61 at 298 K). The temperature dependence of the kinetic isotope effect suggested the symmetrical transition state in the rate-determining step. The rate constants of oxidation of four vicinal diols show excellent correlation with Taft's ∑ σ* values with negative reaction constant, ρz.ast;. The rate of oxidation of ethanediol has been determined in nineteen different solvents. An analysis of the solvent effect indicates the importance of the cation-solvating power of the solvents. A suitable mechanism has been postulated involving the formation of chromate ester in a pre-equilibrium.
Oxidation of some vicinal and non-vicinal diols by morpholinium chlorochromate: A kinetic and mechanistic study
Barthora,Baghmar,Agarwal,Sharma, Vinita
experimental part, p. 677 - 683 (2012/04/10)
The kinetics of oxidation of four vicinal, four non-vicinal diols and two of their monoethers by morpholinium chlorochromate (MCC) have been studied in dimethylsulphoxide (DMSO). The main product of oxidation is the corresponding hydroxycarbonyl compound. The reaction is first order in MCC and the diols. The reaction is catalysed by hydrogen ions. The hydrogen ion dependence is taking the form : kobs = a + b [H+]. The oxidation of [1,1,2,2-2H4]ethanediol exhibits a substantial primary kinetic isotope effect (kH/kD = 5.82 at 298 K). The reaction has been studied in nineteen different organic solvents and the solvent effect has been analysed using Taft's and Swain's multiparametric equations. The temperature dependence of the kinetic isotope effect indicates the presence of a symmetrical transition state in the rate-determining step. A suitable mechanism has been proposed.
