100-10-7Relevant articles and documents
Organocatalyzed and uncatalyzed C=C/C=C and C=C/C=N exchange processes between knoevenagel and imine compounds in dynamic covalent chemistry
Kulchat, Sirinan,Meguellati, Kamel,Lehn, Jean-Marie
, p. 1219 - 1236 (2014)
Molecular diversity generation through reversible component exchange has acquired great importance in the last decade with the development of dynamic covalent chemistry. We explore here the recombination of components linked by C=C and C=N bonds through reversible double-bond formation, and cleavage in C=C/C=C and C=C/C=N exchange processes. The reversibility of the Knoevenagel reaction has been explored, and C=C/C=C C/C exchanges have been achieved among different benzylidenes, under organocatalysis by secondary amines such as L-proline. The substituents of these benzylidenes were shown to play a very important role in the kinetics of the exchange reactions. L-Proline is also used to catalyze the reversible C=C/C=C exchange between Knoevenagel derivatives of barbituric acid and malononitrile. Finally, the interconversion between Knoevenagel derivatives of dimethylbarbituric acid and imines (C=C/C=N exchange) has been studied and was found to occur rapidly in the absence of catalyst. The results of this study pave the way for the extension of dynamic combinatorial chemistry based on C=C/C=C and C=C/C=N exchange systems.
Switching the Cleavage Sites in Palladium on Carbon-Catalyzed Carbon-Carbon Bond Disconnection
Hattori, Tomohiro,Takakura, Ryoya,Ichikawa, Tomohiro,Sawama, Yoshinari,Monguchi, Yasunari,Sajiki, Hironao
, p. 2737 - 2743 (2016)
We have demonstrated a palladium on carbon-catalyzed approach to regioselectively alter the cleavage sites of the C-C bonds of cinnamaldehyde derivatives by a slight change in the reaction conditions in isopropanol under an O2 atmosphere. Styrene derivatives could be selectively formed by the addition of Na2CO3 in association with the dissociation of carbon monoxide, while benzaldehyde derivatives were generated by the addition of CuCl and morpholine instead of Na2CO3. (Chemical Equation Presented).
Iodine-catalyzed oxidative system for cyclization of primary alcohols with o-aminobenzamides to quinazolinones using DMSO as the oxidant in dimethyl carbonate
Ge, Wenlei,Zhu, Xun,Wei, Yunyang
, p. 10817 - 10822 (2013)
The iodine catalyzed one-pot two-step oxidative system for cyclization of primary alcohols with o-aminobenzamides to quinazolinones using DMSO as the oxidant has been achieved, providing a convenient and efficient method for the synthesis of quinazolinones in good to excellent yields via in situ oxidation of primary alcohols to aldehydes. The reaction was carried out in the green solvent DMC, under atmospheric conditions. The procedure is suitable for aromatic or alkyl primary alcohols. The Royal Society of Chemistry 2013.
Cobalt-catalysed selective synthesis of aldehydes and alcohols from esters
Pattanaik, Sandip,Gunanathan, Chidambaram
, p. 7345 - 7348 (2020)
Efficient and selective reduction of esters to aldehydes and alcohols is reported in which a simple cobalt pincer catalyst catalyses both transformations using diethylsilane as a reductant. Remarkably, the reaction selectivity is controlled by the stoichiometry of diethylsilane. This journal is
Silica phenyl sulfonic acid as a solid acid heterogeneous catalyst for chemoselective thioacetalization of carbonyl compounds and dethioacetalization under mild conditions
Veisi, Hojat,Sedrpoushan, Alireza,Zolfigol, Mohammad Ali,Mohanazadeh, Farajollah,Hemmati, Saba
, p. E204-E206 (2013)
Silica phenyl sulfonic acid (SPSA) is an effective catalyst for chemoselective thioacetalization of aldehydes in the presence of ketones under neutral conditions. In addition, a simple and an efficient procedure for deprotection of 1,3-dithianes and 1,3-dithiolanes of aromatic, aliphatic, and α,β-unsaturated aldehydes and ketones in the solvent-free to the corresponding parent carbonyl compounds was successfully carried out with SPSA in excellent yields.
Selective conversion of C=N bonds to their corresponding carbonyl compounds by the tribromoisocyanuric acid/wet SiO2 system as a novel reagent
Habibi, Davood,Zolfigol, Mohammad Ali,Faraji, Ali Reza,Rahmani, Payam
, p. 809 - 814 (2012)
Tribromoisocyanuric acid/wet SiO2 was used for the conversion of C=N bonds to their corresponding carbonyl compounds in oximes, semicarbazones, azines, and Schiff bases. The interesting feature of this system is that in those oximes, semicarbazones, azines, and Schiff bases which have conjugated or unconjugated C=C bonds, the C=N bond will selectively change to the relevant C=O bond while the conjugated or unconjugated C=C bond will remain intact. Springer-Verlag 2011.
Highly active and selective synthesis of imines from alcohols and amines or nitroarenes catalyzed by Pd/DNA in water with dehydrogenation
Tang, Lin,Sun, Huayin,Li, Yunfeng,Zha, Zhenggen,Wang, Zhiyong
, p. 3423 - 3428 (2012)
A direct imination was developed from alcohols and amines under catalysis of Pd/DNA by dehydrogenation without additional oxidant, affording the corresponding imines in moderate to good yields with excellent chemoselectivity. By virtue of the liberated molecular hydrogen, the nitroarenes could also be deoxidized in situ into amines and a one-pot tandem synthesis of imines was achieved from nitroarenes. This heterogeneous catalyst can be recovered and reused at least five times by taking advantage of its water-soluble reversibility. All these conformations were performed smoothly in water under mild conditions, and an atom economical and environmentally benign synthesis was embodied in this imination.
Cooperative catalysis of palladium nanoparticles and cobalt oxide support for formylation of aryl iodides under syngas atmosphere
Hamasaki, Akiyuki,Yasutake, Yutaro,Norio, Takafumi,Ishida, Tamao,Akita, Tomoki,Ohashi, Hironori,Yokoyama, Takushi,Honma, Tetsuo,Tokunaga, Makoto
, p. 146 - 152 (2014)
Formylation of aryl iodides proceeded effectively in the presence of palladium nanoparticles on cobalt oxide under a syngas atmosphere to afford aldehydes up to 91% yield. A cooperative effect between palladium nanoparticles and cobalt species derived from the support was integral to efficient transformation. Both palladium and cobalt were revealed to exist as zero valent metals after H2 treatment from X-ray absorption near edge structure and X-ray diffraction spectra. The catalyst could be reused at least 7 times without significant loss of activity.
Kinetics of Hydrolysis of Some N'-(4-Substituted Benzylidene)salicylohydrazides
Temerk, Yassien M.,Kamal, Mostafa M.,Ahmed, Mohamed E.
, p. 337 - 340 (1984)
The rates of hydrolysis of a series of substituted benzylidenesalicylohydrazide derivatives 40percent (v/v) ethanol-buffer mixture have been investigated by differential pulse polarography.The hydrolysis is catalysed by H+ and its rate follows strictly first-order kinetics.The rate constant decreases with increasing pH up to around pH 3.9, beyond which no measurable reaction was observed; here the protonation of imine begins to be significantly incomplete.The attack of water on the protonated substrate is considered to be the rate-determining step.The effects of pH, molecular structure, and temperature on the reaction rate and the activation energy are reported.Thermodynamic parameters (ΔG(formula), ΔH(formula), and ΔS(fomula)) for the hydrolysis are discussed.
Two-step radiosynthesis of [18F]N-succinimidyl-4-fluorobenzoate ([18F]SFB)
Glaser, Matthias,Arstad, Erik,Luthra, Sajinder K.,Robins, Edward G.
, p. 327 - 330 (2009)
The acylation reagent [18F]N-succinimidyl-4-fluorobenzoate (18F-SFB) has been prepared using a new two-step approach. The starting material p-[18F]fluorobenzaldehyde (18F-FBA) was obtained by an improved radiosy
