3019-04-3Relevant academic research and scientific papers
THE SOLUTION-STATE CONFORMATIONS OF IODOACETONE AND ω-IODOACETOPHENONE
Lumbroso, H.,Liegeois, Ch.,Guerrero, S. A.,Olivato, P. R.,Hase, Y.
, p. 141 - 149 (1987)
A comparison of the experimental dipole moments of iodoacetone and ω-iodoacetophenone in n-hexane, carbon tetrachloride and benzene solution at 30.0 deg C with the values calculated (with inclusion of induced moments through space) for both cis and gauche conformers gives estimates of their (cis):(gauche) conformational ratios in these media.Molecular mechanics calculations show that the cis conformers of iodoacetone and ω-iodoacetophenone are nearly uniplanar, whereas the gauche-conformers of these compounds are characterized by (O=C-CH2-I) dihedral angles of 100.5 and 98.5 deg, respectively.
Reaction kinetics and critical phenomena: Iodination of acetone in isobutyric acid + water near the consolute point
Hu, Baichuan,Baird, James K.
, p. 355 - 359 (2010)
The rate of iodination of acetone has been measured as a function of temperature in the binary solvent isobutyric acid (IBA) + water near the upper consolute point. The reaction mixture was prepared by the addition of acetone, iodine, and potassium iodide to IBA + water at its critical composition of 38.8 mass % IBA. The value of the critical temperature determined immediately after mixing was 25.43 °C. Aliquots were extracted from the mixture at regular intervals in order to follow the time course of the reaction. After dilution of the aliquot with water to quench the reaction, the concentration of triiodide ion was determined by the measurement of the optical density at a wavelength of 565 nm. These measurements showed that the kinetics were zeroth order. When at the end of 24 h the reaction had come to equilibrium, the critical temperature was determined again and found to be 24.83 °C. An Arrhenius plot of the temperature dependence of the observed rate constant, kobs, was linear over the temperature range 27.00-38.00 °C, but between 25.43 and 27.00 °C, the values of kobs fell below the extrapolation of the Arrhenius line. This behavior is evidence in support of critical slowing down. Our experimental method and results are significant in three ways: (1) In contrast to in situ measurements of optical density, the determination of the optical density of diluted aliquots avoided any interference from critical opalescence. (2) The measured reaction rate exhibited critical slowing down. (3) The rate law was pseudo zeroth order both inside and outside the critical region, indicating that the reaction mechanism was unaffected by the presence of the critical point.
A New Chemical Oscillator in a Novel Open Reactor: The ClO2-I2-Acetone System in a Membrane Fed Stirred Tank Reactor
Marlovits, Gabor,Wittmann, Maria,Noszticzius, Zoltan,Gaspar, Vilmos
, p. 5359 - 5364 (1995)
The title reaction was carried out in a new type of semibatch reactor, where iodine or both iodine and chlorine dioxide are fed to the stirred bulk of the reactor through thin and selective silicon rubber membranes.For model calculations the iodine inflow rate and the pseudo-first-order rate constant of the iodide production from iodine were determined experimentally.All other reactions and rate constants were taken from the literature.The period and the duration of the experimentally found and theoretically predicted oscillations agree rather well.An exact electrochemical interpretation of the amplitude of the electrode potential oscillations requires further research.
THE MECHANISM FOR NUCLEOPHILIC SUBSTITUTION OF α-CARBONYL DERIVATIVES. APPLICATION OF THE VALENCE-BOND CONFIGURATION MIXING MODEL.
McLennan, Duncan J.,Pross, Addy
, p. 981 - 984 (1984)
The valence-bond configuration mixing model (VBCM) is applied to the nucleophilic substitution reactions of α-carbonyl derivatives.The model appears to resolve satisfactorily a number of features of these reactions that current mechanisms have not dealt with.These include: (i) the dependence of the rate-enchancing effect of the carbonyl upon the nucleophilic strenght of the entering group, (ii) the unusually large Hammett ? value for the reaction of PhCOCH2Br with substituted pyridines, and (iii) the mechanism by which the rate-enhancing effect of the carbonyl group is transmitted to the reaction centre.
Facile Access to an Active γ-NiOOH Electrocatalyst for Durable Water Oxidation Derived From an Intermetallic Nickel Germanide Precursor
Menezes, Prashanth W.,Yao, Shenglai,Beltrán-Suito, Rodrigo,Hausmann, J. Niklas,Menezes, Pramod V.,Driess, Matthias
supporting information, p. 4640 - 4647 (2021/02/05)
Identifying novel classes of precatalysts for the oxygen evolution reaction (OER by water oxidation) with enhanced catalytic activity and stability is a key strategy to enable chemical energy conversion. The vast chemical space of intermetallic phases offers plenty of opportunities to discover OER electrocatalysts with improved performance. Herein we report intermetallic nickel germanide (NiGe) acting as a superior activity and durable Ni-based electro(pre)catalyst for OER. It is produced from a molecular bis(germylene)-Ni precursor. The ultra-small NiGe nanocrystals deposited on both nickel foam and fluorinated tin oxide (FTO) electrodes showed lower overpotentials and a durability of over three weeks (505 h) in comparison to the state-of-the-art Ni-, Co-, Fe-, and benchmark NiFe-based electrocatalysts under identical alkaline OER conditions. In contrast to other Ni-based intermetallic precatalysts under alkaline OER conditions, an unexpected electroconversion of NiGe into γ-NiIIIOOH with intercalated OH?/CO32? transpired that served as a highly active structure as shown by various ex situ methods and quasi in situ Raman spectroscopy.
1,2-Dibromoethane and KI mediated α-acyloxylation of ketones with carboxylic acids
Wang, Xujie,Li, Gangsheng,Yang, Yanan,Jiang, Jianshuang,Feng, Ziming,Zhang, Peicheng
supporting information, p. 711 - 714 (2019/09/30)
The 1,2-dibromoethane- and KI-mediated α-acyloxylation of ketones is reported in moderate to good yield without the use of transition metals and strong oxidants. Various acids are well tolerated with wide functional group compatibility. An 1,2-dibromoethane- and KI-catalysed reaction mechanism is proposed based on the results of control experiments.
Reaction of 4-hydroxycoumarin or its O-substituted derivatives with diatomic interhalogens: ICl and IBr
Popa, Marcel Mirel,Draghici, Constantin,Barbu, Loredana,Dumitrescu, Denisa E.,Dumitrascu, Florea
supporting information, p. 344 - 350 (2017/02/10)
Herein, we present some aspects regarding the iodination/bromination of 4-hydroxycoumarin or its O-methyl or O-acetyl derivatives with iodine monochloride or iodine monobromide as halogenation reagents. Also, the investigation of photochemical transformation of the three 3-iodocoumarins was investigated for the first time.
Synthesis and antiviral evaluation of 4′-(1,2,3-triazol-1-yl) thymidines
Vernekar, Sanjeev Kumar V.,Qiu, Li,Zacharias, Jeana,Geraghty, Robert J.,Wang, Zhengqiang
supporting information, p. 603 - 608 (2014/05/06)
Non-obligate chain terminating nucleosides with a linear substituent (azido or ethynyl group) at the 4′ position represent an important class of compounds in antiviral discovery, particularly against hepatitis C virus (HCV) and human immunodeficiency virus (HIV). We have previously shown that 3′-azidothymidine (AZT)-derived 1,2,3-triazoles can be potent inhibitors of HIV-1. To gauge the medicinal chemistry impact of functionalizing the 4′-linear substituent and possibly generate novel antiviral nucleoside scaffolds, we have explored azide-alkyne cycloaddition reactions with 4′-azidothymidine (ADRT). The Ru-mediated reaction failed and the Cu-catalyzed variant generated 1,2,3-triazoles (9a-y) with only modest yields and efficiencies, indicating a substantial steric barrier around the 4′-azido group. Antiviral screening identified a few triazole analogues moderately active against HIV-1 (18-62% inhibition at 10 μM) and/or influenza A virus (15-50% inhibition at 10 μM), and none active against West Nile virus (WNV) or HCV. These results suggest that the linear 4′ azido group of ADRT may be essential for target binding and that its chemical manipulation could largely compromise antiviral potency. This journal is the Partner Organisations 2014.
New simple synthesis of quinoline-4-carbonitriles
Bujok, Robert,Wrobel, Zbigniew,Wojciechowski, Krzysztof,Trawczyski, Adam
, p. 2682 - 2686,5 (2012/12/12)
Alkylation of 2-nitrobenzyl cyanides with α-halomethyl ketones furnishes ketonitriles which upon reduction with tin(II) chloride form quinoline-4-carbonitriles in good yields.
Diethyl [Nitro(diazo)methyl]phosphonate: Synthesis and reactivity towards alkenes
Chemagin, Andrey V.,Yashin, Nikolai V.,Grishin, Yuri K.,Kuznetsova, Tamara S.,Zefirov, Nikolai S.
scheme or table, p. 259 - 266 (2010/03/24)
A novel and convenient synthesis of diethyl [nitro(di-azo)methyl] phosphonate and its reactions with various alkenes are described. The reactivity of diethyl [nitro(diazo)methyl]phosphonate is shown to be dependent on the structure of the alkene. A number of cyclopropyl-nitrophosphonates were obtained. Georg Thieme Verlag Stuttgart.
