scholarly journals Application of Diethylzinc/propyl Gallate Catalytic System for Ring-Opening Copolymerization of rac-Lactide and ε-Caprolactone

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4168 ◽  
Author(s):  
Wyrębiak ◽  
Oledzka ◽  
Figat ◽  
Sobczak
Keyword(s):  
Catalytic System ◽  
Propyl Gallate ◽  
Ring Opening ◽  
Reaction Conditions ◽  
Catalytic Systems ◽  
Cyclic Esters ◽  
Biomedical Polymers ◽  
Low Toxicity ◽  
High Yields ◽  
Polymerization Method

Biodegradable polyesters gain significant attention because of their wide potential biomedical applications. The ring-opening polymerization method is widely used to obtain such polymers, due to high yields and advantageous properties of the obtained material. The preparation of new, effective, and bio-safe catalytic systems for the synthesis of biomedical polymers is one of the main directions of the research in modern medical chemistry. The new diethylzinc/propyl gallate catalytic system was first used in the copolymerization of ε-caprolactone and rac-lactide. In this paper, the activity of the new zinc-based catalytic system in the copolymerization of cyclic esters depending on the reaction conditions was described. The microstructure analysis of the obtained copolyesters and their toxicity studies were performed. Resulted copolyesters were characterized by low toxicity, moderate dispersity (1.19–1.71), varying randomness degree (0.18–0.83), and average molar mass (5300–9800 Da).

scholarly journals Ring-Opening Copolymerization of Cyclohexene Oxide and Cyclic Anhydrides Catalyzed by Bimetallic Scorpionate Zinc Catalysts

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1651
Author(s):  
Felipe de la Cruz-Martínez ◽  
Marc Martínez de Sarasa Buchaca ◽  
Almudena del Campo-Balguerías ◽  
Juan Fernández-Baeza ◽  
Luis F. Sánchez-Barba ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Mechanism ◽  
Catalytic System ◽  
Phthalic Anhydride ◽  
Ring Opening ◽  
High Selectivity ◽  
Zinc Complexes ◽  
Cyclohexene Oxide ◽  
Reaction Conditions ◽  
Cyclic Anhydrides

The catalytic activity and high selectivity reported by bimetallic heteroscorpionate acetate zinc complexes in ring-opening copolymerization (ROCOP) reactions involving CO2 as substrate encouraged us to expand their use as catalysts for ROCOP of cyclohexene oxide (CHO) and cyclic anhydrides. Among the catalysts tested for the ROCOP of CHO and phthalic anhydride at different reaction conditions, the most active catalytic system was the combination of complex 3 with bis(triphenylphosphine)iminium as cocatalyst in toluene at 80 °C. Once the optimal catalytic system was determined, the scope in terms of other cyclic anhydrides was broadened. The catalytic system was capable of copolymerizing selectively and efficiently CHO with phthalic, maleic, succinic and naphthalic anhydrides to afford the corresponding polyester materials. The polyesters obtained were characterized by spectroscopic, spectrometric, and calorimetric techniques. Finally, the reaction mechanism of the catalytic system was proposed based on stoichiometric reactions.

scholarly journals Cs2CO3/[bmim]Br as an Efficient, Green, and Reusable Catalytic System for the Synthesis of N-Alkyl Derivatives of Phthalimide under Mild Conditions

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Alireza Hasaninejad ◽  
Abdolkarim Zare ◽  
Ahmad Reza Moosavi-Zare ◽  
Fatemeh Khedri ◽  
Rahimeh Rahimi ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Catalytic System ◽  
Reaction Times ◽  
Catalytic Amount ◽  
Conjugate Addition ◽  
Reaction Conditions ◽  
Mild Conditions ◽  
Alkyl Derivatives ◽  
High Yields ◽  
Derivatives Of

Aza-conjugate addition of phthalimide to α,β-unsaturated esters efficiently achieves in the presence of catalytic amount of Cs2CO3 and ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) under mild reaction conditions (70°C) to afford N-alkyl phthalimides in high yields and relatively short reaction times.

scholarly journals Green Organic Solvent-Free Oxidation of Alkylarenes with tert-Butyl Hydroperoxide Catalyzed by Water-Soluble Copper Complex

2020 ◽  
Vol 18 (1) ◽  
pp. 165-174 ◽  
Author(s):  
Abdelaziz Nait Ajjou ◽  
Ateeq Rahman
Keyword(s):  
Organic Solvent ◽  
Catalytic System ◽  
Solvent Free ◽  
Water Soluble ◽  
Catalytic Systems ◽  
Butyl Hydroperoxide ◽  
Benzylic Alcohols ◽  
Tert Butyl Hydroperoxide ◽  
Solvent Free Conditions ◽  
High Yields

AbstractDifferent benzylic compounds were efficiently oxidized to the corresponding ketones with aqueous 70% tert-butyl hydroperoxide (TBHP) and the catalytic system composed of CuCl2.2H2O and 2,2’-biquinoline-4,4’-dicarboxylic acid dipotassium salt (BQC). The catalytic system CuCl2/BQC/TBHP allows obtaining high yields at room temperature under organic solvent-free conditions. The interest of this system lies in its cost effectiveness and its benign nature towards the environment. Benzylic tertbutylperoxy ethers and benzylic alcohols were observed and suggested as the reaction intermediates. Analysis of organic products by atomic absorption did not show any contamination with copper metal. In terms of efficiency, CuCl2/BQC system is comparable or superior to the most of the catalytic systems described in the literature and which are based on toxic organic solvent.

Heterogeneous catalysts based on built-in N-heterocyclic carbenes with high removability, recoverability and reusability for ring-opening polymerization of cyclic esters

2019 ◽  
Vol 10 (12) ◽  
pp. 1526-1536 ◽  
Author(s):  
Wen Liu ◽  
Guo-Qiang Tian ◽  
Dan-Dan Yang ◽  
Gang Wu ◽  
Si-Chong Chen ◽  
...  
Keyword(s):  
Ring Opening ◽  
Heterogeneous Catalysts ◽  
Ring Opening Polymerization ◽  
Heterocyclic Carbenes ◽  
Catalytic Systems ◽  
Cyclic Esters ◽  
Metal Free ◽  
Critical Issues ◽  
New Generation

Both activity and reusability are critical issues for developing new generation metal-free catalytic systems.

scholarly journals BIMP Catalyzed 1,3-Prototropic Shift for the Highly Enantioselective Synthesis of Conjugated Cyclohexenones

2020 ◽  
Author(s):  
Jonathan Golec ◽  
Eve Carter ◽  
John W. Ward ◽  
William Whittingham ◽  
Luis Simon ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Linear Regression ◽  
Catalytic System ◽  
Reaction Times ◽  
Multivariate Linear Regression ◽  
Enantioselective Synthesis ◽  
Reaction Conditions ◽  
High Yields ◽  
Experimental Findings ◽  
Good Agreement

<div>A bifunctional iminophosphorane (BIMP) catalyzed enantioselective synthesis of α,β-unsaturated cyclohexenones via a facially selective 1,3-prototropic shift of β,γ-unsaturated prochiral isomers, under mild reaction conditions and in short reaction times, on a range of structurally diverse substrates, is reported. α,β-Unsaturated cyclohexenone products primed for downstream derivatisation were obtained in high yields (up to 99%) and consistently high enantioselectivity (up to 99% ee). In-depth studies into the reaction mechanism and origins of enantioselectivity, including multivariate linear regression of TS energy, were carried out computationally on the catalytic system and the obtained data was found to be in good agreement with experimental findings.</div>

scholarly journals BIMP Catalyzed 1,3-Prototropic Shift for the Highly Enantioselective Synthesis of Conjugated Cyclohexenones

2020 ◽  
Author(s):  
Jonathan Golec ◽  
Eve Carter ◽  
John W. Ward ◽  
William Whittingham ◽  
Luis Simon ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Linear Regression ◽  
Catalytic System ◽  
Reaction Times ◽  
Multivariate Linear Regression ◽  
Enantioselective Synthesis ◽  
Reaction Conditions ◽  
High Yields ◽  
Experimental Findings ◽  
Good Agreement

<div>A bifunctional iminophosphorane (BIMP) catalyzed enantioselective synthesis of α,β-unsaturated cyclohexenones via a facially selective 1,3-prototropic shift of β,γ-unsaturated prochiral isomers, under mild reaction conditions and in short reaction times, on a range of structurally diverse substrates, is reported. α,β-Unsaturated cyclohexenone products primed for downstream derivatisation were obtained in high yields (up to 99%) and consistently high enantioselectivity (up to 99% ee). In-depth studies into the reaction mechanism and origins of enantioselectivity, including multivariate linear regression of TS energy, were carried out computationally on the catalytic system and the obtained data was found to be in good agreement with experimental findings.</div>

scholarly journals REACTION OF 2-HETARYL-2-(DIHYDROFURAN-2(3H)-ILIDEN)ACETONITRILES WITH AROMATIC AMINES

2020 ◽  
pp. 47-51
Author(s):  
R. Shemehen ◽  
O. Khilya ◽  
Yu. Volovenko
Keyword(s):  
Aromatic Amines ◽  
Ring Opening ◽  
Catalytic Amount ◽  
Building Blocks ◽  
Heterocyclic Ring ◽  
Ring Closure ◽  
Reaction Conditions ◽  
Ring Opening Reaction ◽  
Ring Transformations ◽  
High Yields

This article reports on the reaction of 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles with aromatic amines as N-nucleophiles. 2-Hetaryl-2-(furanyl-2-ylidene)acetonitriles represent versatile building blocks in syntheses of ω-(N-aryl)alkyl substituted heterocycles due to the presence of 1,3-bielectrophilic acrylonitrile fragment functionalized with unsaturated heterocyclic ring and nucleophilic azaheterocyclic moiety. The carbonyl group masked within the N-arylpyrrolidinylidene fragment which undergoes a ring opening through the reaction with nucleophiles. So, a method for the synthesis of 2-hetaryl-6-hydroxy-3-(arylamino)hex-2-enenitriles and 2-hetaryl-2-(N-arylpyrrolidin-2-ylidene)acetonitriles has been developed by us. The proposed scheme is based on the available reagents using. As a result of Michael addition, the aromatic amines to 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles followed by ring transformations has formed two types of products, depending on the reaction conditions. The reaction of substituted furanylylideneacetonitriles with aromatic amines proceeds in good to high yields affording the corresponding 3-(arylamino)hex-2-enenitriles and 2-(N-arylpyrrolidin-2-ylidene)acetonitriles derivatives. The stereochemistry of the ring-opening reaction follows the rules of a classical SN2 mechanism. The resulting linear products can be cyclized to 2-hetaryl-2-(furanyl-2-ylidene)acetonitriles in high yields by treatment with the catalytic amount of acid or the equimolar amount of aromatic amines. Under these conditions 2-hetaryl-6-hydroxy-3-(arylamino)hex-2-enenitriles arising from reaction gives the ring closure. Since both ring-opening and cyclisation occur with fixed stereochemistry the reaction appears a valuable modification to the preparation of acetonitriles derivatives.

New homoleptic bis(pyrrolylpyridiylimino) Mg(ii) and Zn(ii) complexes as catalysts for the ring opening polymerization of cyclic esters via an “activated monomer” mechanism

2017 ◽  
Vol 46 (36) ◽  
pp. 12217-12225 ◽  
Author(s):  
Ilaria D'Auria ◽  
Consiglia Tedesco ◽  
Mina Mazzeo ◽  
Claudio Pellecchia
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Cyclic Esters ◽  
High Yields

The reaction of MgBu2 and ZnEt2 or Zn{N[Si(CH3)3]2}2 with a tridentate monoanionic pyrrolylpyridiylimino [N−,N,N] proligand gave homoleptic species, as exclusive products, in high yields.

Cyclic Phenylboronates of Ecdysteroids as Products of Regiospecific Reaction with Phenylboronic Acid

1993 ◽  
Vol 58 (3) ◽  
pp. 612-618 ◽  
Author(s):  
Jaroslav Píš ◽  
Jiří Hykl ◽  
Miloš Buděšínský ◽  
Juraj Harmatha
Keyword(s):  
Aqueous Solutions ◽  
Carboxylic Acids ◽  
Nmr Spectra ◽  
Phenylboronic Acid ◽  
Side Chain ◽  
Reaction Conditions ◽  
Cyclic Esters ◽  
H Nmr ◽  
High Yields

The diol system in the side-chain of ecdysteroids reacts with phenylboronic acid under formation of cyclic esters. Phenylboronates of ecdysteroids I - V were prepared. The regiospecific reaction course was confirmed by 1H NMR spectra of the products. The reaction conditions were studied for 20-hydroxyecdysone (I). The phenylboronate can be prepared in high yields even in aqueous solutions. The liberation of the ecdysteroid I from the corresponding phenylboronate VI was performed using various reagents - diols or carboxylic acids.

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