48140-35-8Relevant academic research and scientific papers
Activated Self-Resolution and Error-Correction in Catalytic Reaction Networks**
Schaufelberger, Fredrik,Ramstr?m, Olof
supporting information, p. 10335 - 10340 (2021/05/07)
Understanding the emergence of function in complex reaction networks is a primary goal of systems chemistry and origin-of-life studies. Especially challenging is to create systems that simultaneously exhibit several emergent functions that can be independently tuned. In this work, a multifunctional complex reaction network of nucleophilic small molecule catalysts for the Morita-Baylis-Hillman (MBH) reaction is demonstrated. The dynamic system exhibited triggered self-resolution, preferentially amplifying a specific catalyst/product set out of a many potential alternatives. By utilizing selective reversibility of the products of the reaction set, systemic thermodynamically driven error-correction could also be introduced. To achieve this, a dynamic covalent MBH reaction based on adducts with internal H-transfer capabilities was developed. By careful tuning of the substituents, rate accelerations of retro-MBH reactions of up to four orders of magnitude could be obtained. This study thus demonstrates how efficient self-sorting of catalytic systems can be achieved through an interplay of several complex emergent functionalities.
Inhibition by Water during Heterogeneous Br?nsted Acid Catalysis by Three-Dimensional Crystalline Organic Salts
Belokon, Yuri N.,Gak, Alexander,Khakina, Ekaterina,Khrustalev, Victor N.,Korlyukov, Alexander A.,Kuznetsova, Svetlana,Li, Han,Lobanov, Nikolai,Nelyubina, Yulia,North, Michael,Peregudov, Alexander S.,Riazanov, Vladimir,Zhereb, Vladimir
, p. 6364 - 6372 (2021/10/20)
A new self-assembled and self-healing class of metal free, recyclable, heterogeneous Br?nsted acid catalysts has been developed by the protonation of aniline derivatives (tetrakis(4-aminophenyl)methane, leuco-crystal violet, benzidine, and p-phenylenediamine) with aromatic sulfonic acids (tetrakis(phenyl-4-sulfonic acid)methane, and 2,6-naphthalenedisulfonic acid). As a result, five three-dimensional crystalline organic salts (F-1a, F-1b, F-1c, F-2, and F-3) were obtained, linked by hydrogen bonds and additionally stabilized by the opposite charges of the components. Frameworks F-2 and F-3 were prepared for the first time and characterized by elemental analysis, X-ray structural analysis (for F-2), thermogravimetry, SEM, and FTIR spectroscopy. The catalytic activities of crystalline organic salts F-1-3 have been explored in industrially important epoxide ring-opening and acetal formation reactions. The presence of encapsulated water inside frameworks F-1a and F-2 had an inhibitory effect on the performance of the catalysts. X-ray diffraction analysis of hydrated and dehydrated samples of F-1a and F-2 indicated that water of crystallization served as a cross-linking agent, diminishing the substrate induced "breathing"affinities of the frameworks.
Practical acetalization and transacetalization of carbonyl compounds catalyzed by recyclable PVP-I
Cao, Fu-Rong,Lu, Guangying,Ren, Jiangmeng,Wang, Di,Zeng, Bu-Bing
, (2021/06/21)
A novel PVP-I catalyzed acetalizations/transacetalizations of carbonyl compounds has been developed processing with a mild and easy handling fashion. Different types of Acyclic and cyclic acetals were prepared from carbonyl compounds or their acetals successfully. Further applications of newly developed catalytic combination were testified. This protocol featured with simplicity of operation, mild reaction condition, short reaction time, recyclable of catalyst and broad substrates scope with excellent yields.
Preparation method of ambroxol hydrochloride
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Paragraph 0034-0047; 0068-0071, (2020/05/14)
The invention relates to a preparation method of ambroxol hydrochloride, and the method comprises the following steps: carrying out aldehyde group protection on o-nitrobenzaldehyde, and reducing hydrazine hydrate in the presence of a catalyst NiCoB/TiO2 to obtain a compound 3; carrying out bromination reaction on the compound 3 under the action of molecular bromine and hydrogen peroxide, and carrying out deprotection to generate a compound 2; and carrying out aldehyde reductive amination reaction with trans-4-aminocyclohexanol under the action of catalysts NaBH (OAc) 3 and LiClO4, and salifying to obtain the ambroxol hydrochloride. The method has the advantages of mild conditions, simple steps, environmental friendliness, easily stored raw materials and high yield, and is suitable for industrial production.
Chiroptical Asymmetric Reaction Screening via Multicomponent Self-Assembly
De Los Santos, Zeus A.,Wolf, Christian
supporting information, p. 13517 - 13520 (2016/10/31)
Self-assembly of a stereodynamic phosphine ligand, Pd(II), and a chiral amine, amino alcohol, or amino acid generates characteristic UV and CD signals that can be used for quantitative stereochemical analysis of the bound substrate. A robust mix-and-measure chiroptical sensing protocol has been developed and used to determine the absolute configuration, ee, and yield of an amine produced by Ir-catalyzed asymmetric hydrogenation of an iminium salt. The analysis requires only 1 mg of the crude reaction mixture and minimizes cost, labor, time, and waste.
Synthesis and characterization of a tetracationic acidic organic salt and its application in the synthesis of bis(indolyl)methanes and protection of carbonyl compounds
Halimehjani, Azim Ziyaei,Hooshmand, Seyyed Emad,Shamiri, Elham Vali
, p. 21772 - 21777 (2015/03/18)
A new tetracationic acidic organic salt (TCAOS) based on DABCO was prepared, characterized and applied as an eco-friendly, powerful and reusable catalyst for the synthesis of bis(indolyl)methanes from indoles and carbonyl compounds in water with high turnover frequency (TOF). Also, this catalyst was successfully applied for acetalization of carbonyl compounds with diols under solvent-free conditions.
Acetalization of aldehydes and ketones over H4[SiW 12O40] and H4[SiW12O 40]/SiO2
Zhao, Shen,Jia, Yueqing,Song, Yu-Fei
, p. 2618 - 2625 (2014/07/22)
H4[SiW12O40] (H-SiW12) is demonstrated to be able to efficiently catalyze the acetalization of aldehydes and ketones with ethylene glycol and 1,3-propanediol. Nevertheless, the possible leaching and the recycling of H-SiW12 are two major disadvantages that largely restrict its further application in industry. Moreover, H 4[SiW12O40] tends to deactivate strong proton sites due to the small surface area of 10 m2 g-1. Due to interactions with surface silanol groups, the proton sites of polyoxometalates (POMs) on SiO2 are less susceptible to deactivation. As such, immobilization of H4[SiW12O40] onto SiO 2 leads to the heterogeneous catalyst H4[SiW 12O40]/SiO2 (H-SiW12/SiO 2), which can catalyze the acetalization of aldehydes and ketones with ethylene glycol and 1,3-propanediol selectively and efficiently without the need of a drying agent. The acetalization process can proceed smoothly at a relatively low temperature under solvent-free conditions. The catalyst of H 4[SiW12O40]/SiO2 can be recycled at least ten times without an obvious decrease in its catalytic activity. As far as we know, the TONs of the H-SiW12/SiO2-catalyzed acetalization of cyclohexanone with ethylene glycol, and benzaldehyde with 1,3-propanediol are the highest reported so far.
A facile and efficient protocol for esterification and acetalization in a PEG1000-D(A)IL/toluene thermoregulated catalyst-media combined systems
Wang, Yinglei,Zhi, Huizhen,Luo, Jun
, p. 46 - 52 (2013/09/23)
A novel efficient and recyclable temperature-dependent biphasic catalyst and reaction media combined system comprised of PEG-1000 linked dicationic acidic ionic liquid and toluene was developed and applied in esterification of aromatic acids and acetalization of aromatic aldehydes with good to excellent yields. This system is characteristic of temperature-dependent reversible biphasic property, simple and facile recyclability, high catalytic activity and extensive substrate and reaction adaptability.
Mesoporous sulfated zirconia mediated acetalization reactions
Sinhamahapatra, Apurba,Sutradhar, Narottom,Ghosh, Malay,Bajaj, Hari C.,Panda, Asit B.
experimental part, p. 87 - 93 (2012/04/10)
A novel, convenient, one step synthetic procedure for the synthesis of mesoporous sulfated zirconia (m-SZ) using zirconium carbonate complex and its use as solid acid catalyst for the acetalization of different carbonyl compound is reported. The high specific BET surface area (234 m2 g -1) of m-SZ is achieved after the removal of the surfactant (cetyltrymethylammonium bromide, CTAB) through calcination at 550 °C for 6 h. Microscopic analysis indicated the presence of spherical particles with worm like pores. DRIFT (diffuse reflectance FTIR) of pyridine adsorbed m-SZ and NH3-TPD (temperature programmed desorption) analysis suggested the presence of appreciable amount of Bro?nsted acid sites. The synthesized m-SZ showed high catalytic activity towards protection of carbonyl compounds through acetal/ketal formation. For the open ketal (from cyclohexanone and methanol) 97% conversion with 100% selectivity was obtained in 1 h at room temperature under solvent free condition. The catalyst can be easily recycled after separation from the reaction system without considerable loss in catalytic activity.
Acetalization of carbonyl compounds catalyzed by bismuth triflate under solvent-free conditions
Aliyan, Hamid,Fazaeli, Razieh,Massah, Ahmad Reza,Momeni, Ahmad Reza,Naghash, Hamid Javaherian,Moeinifard, Behzad
experimental part, p. 873 - 876 (2012/04/05)
Carbonyl compounds were converted to the corresponding 1,3-dioxolanes and 1,3-dioxanes with ethylene glycol and 1,3-propandiol in the presence of bismuth triflate under solvent-free conditions. In addition, high chemoselective protection of aldehydes in the presence of ketones has been achieved.
