scholarly journals General approach to prepare polymers bearing pendant isocyanate groups

2020 ◽  
Vol 11 (32) ◽  
pp. 5140-5146
Author(s):  
Rodrigo Navarro ◽  
Carolina García ◽  
Juan Rodríguez-Hernández ◽  
Carlos Elvira ◽  
Angel Marcos-Fernández ◽  
...  
Keyword(s):  
Synthetic Approach ◽  
Side Chains ◽  
Linear Polymers ◽  
Reaction Conditions

A versatile synthetic approach for the easy preparation, under smooth reaction conditions, of diverse classes of linear polymers bearing aliphatic or aromatic isocyanate groups in the side chains is described.

Diversity-Oriented Synthesis via Catalyst-Free Addition of Ketones to [e]-Fused 1H-Pyrrole-2,3-diones

Synthesis ◽  
2018 ◽  
Vol 50 (24) ◽  
pp. 4897-4904 ◽  
Author(s):  
Ekaterina Stepanova ◽  
Andrey Maslivets ◽  
Svetlana Kasatkina ◽  
Maksim Dmitriev
Keyword(s):  
Intramolecular Cyclization ◽  
Aromatic Hydrocarbons ◽  
Michael Addition ◽  
Aldol Reaction ◽  
Synthetic Approach ◽  
Reaction Conditions ◽  
Diversity Oriented Synthesis ◽  
Catalyst Free ◽  
Solvent Free Conditions ◽  
Reaction Proceeds

A facile synthetic approach towards two distinct pyrrole-based heterocyclic scaffolds has been developed by the interaction of 1H-pyrrole-2,3-diones fused at the [e]-side to a 1,4-benzoxazin-2-one or quinoxalin-2(1H)-one moiety with ketones. The described interaction proceeds either as an aldol reaction or as a Michael addition/intramolecular cyclization depending on the reaction conditions. The disclosed aldol reaction proceeds with good diastereoselectivity under catalyst-free conditions when the reaction is carried out in aromatic hydrocarbons. Products of the cascade Michael addition/intramolecular cyclization reaction are predominantly formed under catalyst-free and solvent-free conditions. The proposed strategy provides facile access to pharmaceutically interesting pyrrole-based polyheterocycles.

scholarly journals The Study of the Reaction of Pectin-Ag(0) Nanocomposites Formation

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Nadezhda Viktorovna Ivanova ◽  
Natalya Nikolaevna Trofimova ◽  
Lydmila Alexandrovna Es'kova ◽  
Vasilyi Anatolievich Babkin
Keyword(s):  
Aqueous Solutions ◽  
Larix Sibirica ◽  
Side Chains ◽  
Chemical Transformations ◽  
Reaction Conditions ◽  
Rhamnogalacturonan I ◽  
Spectroscopic Analyses ◽  
Furanose Form ◽  
Branched Structure ◽  
C Nmr

Pectin polysaccharides (PSs) were isolated from a bark of Larix sibirica Ledeb. Structure of PS fragments determined by chemical transformations, chromatography, and spectroscopic analyses was found to be a linear galacturonane comprising 1,4-linked α-D-GalpA residues and a rhamnogalacturonan I (RG-I). The fifth part of galacturonane residues was methyl esterified at at C-2 and/or C-3 and C-6 atoms. Some of RG-I side chains were identified as arabinogalactan subunits with highly branched structure consisting of linear backbone with3,6)-β-D-Galp-(1residues, substituted at C-6 by neutral side chains. This side chains contained2,5)-α-L-Araf-(1and3,5)-α-L-Araf-(1residues and terminal arabinose in the pyranose and furanose form. It was found that “pectin-Ag(0)” nanobiocomposites were formed via the interaction between PS aqueous solutions and silver nitrate, with PS playing both reducing and stabilizing functions. It was shown that the content of Ag(0) particles in “pectin-Ag(0)” depended on the reaction conditions and can range from 0.1 to 72 %, the size of Ag(0) particles being 3–27 nm. Using 13C NMR technique, it was revealed that PS underwent destructive changes and they they were more considerable, more than the lot of Ag(I) that was inputed into the reactionary medium.

scholarly journals Integrated and Metal Free Synthesis of Dimethyl Carbonate and Glycidol from Glycerol Derived 1,3-Dichloro-2-propanol via CO2 Capture

2021 ◽  
Vol 3 (4) ◽  
pp. 685-698
Author(s):  
Santosh Khokarale ◽  
Ganesh Shelke ◽  
Jyri-Pekka Mikkola
Keyword(s):  
Co2 Capture ◽  
Dimethyl Carbonate ◽  
Chemical Species ◽  
Cyclic Carbonate ◽  
Chloride Ions ◽  
Synthetic Approach ◽  
Integrated Process ◽  
Reaction Conditions ◽  
Metal Free ◽  
Analysis Technique

Dimethyl carbonate (DMC) and glycidol are considered industrially important chemical entities and there is a great benefit if these moieties can be synthesized from biomass-derived feedstocks such as glycerol or its derivatives. In this report, both DMC and glycidol were synthesized in an integrated process from glycerol derived 1,3-dichloro-2-propanol and CO2 through a metal-free reaction approach and at mild reaction conditions. Initially, the chlorinated cyclic carbonate, i.e., 3-chloro-1,2-propylenecarbonate was synthesized using the equivalent interaction of organic superbase 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) and 1,3-dichloro-2-propanol with CO2 at room temperature. Further, DMC and glycidol were synthesized by the base-catalyzed transesterification of 3-chloro-1,2-propylenecarbonate using DBU in methanol. The synthesis of 3-chloro-1,2-propylenecarbonate was performed in different solvents such as dimethyl sulfoxide (DMSO) and 2-methyltetrahydrofuran (2-Me-THF). In this case, 2-Me-THF further facilitated an easy separation of the product where a 97% recovery of the 3-chloro-1,2-propylenecarbonate was obtained compared to 63% with DMSO. The use of DBU as the base in the transformation of 3-chloro-1,2-propylenecarbonate further facilitates the conversion of the 3-chloro-1,2 propandiol that forms in situ during the transesterification process. Hence, in this synthetic approach, DBU not only eased the CO2 capture and served as a base catalyst in the transesterification process, but it also performed as a reservoir for chloride ions, which further facilitates the synthesis of 3-chloro-1,2-propylenecarbonate and glycidol in the overall process. The separation of the reaction components proceeded through the solvent extraction technique where a 93 and 89% recovery of the DMC and glycidol, respectively, were obtained. The DBU superbase was recovered from its chlorinated salt, [DBUH][Cl], via a neutralization technique. The progress of the reactions as well as the purity of the recovered chemical species was confirmed by means of the NMR analysis technique. Hence, a single base, as well as a renewable solvent comprising an integrated process approach was carried out under mild reaction conditions where CO2 sequestration along with industrially important chemicals such as dimethyl carbonate and glycidol were synthesized.

scholarly journals Biocatalytic Approach to Chiral β-Nitroalcohols by Enantioselective Alcohol Dehydrogenase-Mediated Reduction of α-Nitroketones

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 308 ◽  
Author(s):  
Francesca Tentori ◽  
Elisabetta Brenna ◽  
Danilo Colombo ◽  
Michele Crotti ◽  
Francesco Gatti ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Alcohol Dehydrogenase ◽  
Hydrolytic Degradation ◽  
Building Blocks ◽  
Synthetic Approach ◽  
Reaction Conditions ◽  
Alcohol Dehydrogenases ◽  
The Stability ◽  
Mediated Reduction

Chiral β-nitroalcohols are important building blocks in organic chemistry. The synthetic approach that is based on the enzyme-mediated reduction of α-nitroketones has been scarcely considered. In this work, the use of commercial alcohol dehydrogenases (ADHs) for the reduction of aromatic and aliphatic nitroketones is investigated. High conversions and enantioselectivities can be achieved with two specific ADHs, affording either the (S) or (R)-enantiomer of the corresponding nitroalcohols. The reaction conditions are carefully tuned to preserve the stability of the reduced product, and to avoid the hydrolytic degradation of the starting substrate. The further manipulation of the enantioenriched nitroalcohols into Boc-protected amminoalcohols is also described.

Thiol-reactive thiosulfonate group containing copolymers: facile entry to disulfide-mediated polymer conjugation and redox-responsive functionalizable networks

2020 ◽  
Vol 11 (10) ◽  
pp. 1763-1773 ◽  
Author(s):  
Mehmet Arslan ◽  
Rana Sanyal ◽  
Amitav Sanyal
Keyword(s):  
Synthetic Approach ◽  
Side Chains ◽  
Reactive Polymers ◽  
Disulfide Linkages ◽  
Redox Responsive ◽  
Polymer Conjugation

Herein, we report a synthetic approach to thiol-reactive polymers containing methanethiosulfonate groups as side chains, and demonstrate their application in post-polymerization functionalization through reversible disulfide linkages.

A Synthetic Strategy for 2-Alkylchromanones: Fe(III)-Catalyzed ­Reductive Cross-Coupling of Unactivated Alkenes with Chromones

Synlett ◽  
2018 ◽  
Vol 29 (14) ◽  
pp. 1851-1856 ◽  
Author(s):  
Ji-Yu Wang ◽  
Xu-Ling Chen ◽  
Yu Dong ◽  
Lei Tang ◽  
Xiao-Mei Zhang
Keyword(s):  
Cross Coupling ◽  
Synthetic Approach ◽  
Reaction Conditions ◽  
Synthetic Strategy ◽  
Plausible Mechanism

A new synthetic approach for 2-alkylchromanones utilizing Fe (III)-catalyzed reductive cross-coupling of olefins with chromones has been developed. The reaction conditions are mild, and various substituted alkenes are applicable to the process. Moreover, control experiments were conducted, and a plausible mechanism is proposed.

scholarly journals Controlling the mode of operation of organic transistors through side-chain engineering

2016 ◽  
Vol 113 (43) ◽  
pp. 12017-12022 ◽  
Author(s):  
Alexander Giovannitti ◽  
Dan-Tiberiu Sbircea ◽  
Sahika Inal ◽  
Christian B. Nielsen ◽  
Enrico Bandiello ◽  
...  
Keyword(s):  
Operation Mode ◽  
Triethylene Glycol ◽  
Organic Transistors ◽  
Synthetic Approach ◽  
Side Chains ◽  
Semiconductor Interface ◽  
Transistor Channel ◽  
Fast Switching ◽  
Electrochemical Transistor ◽  
Mode Of Operation

Electrolyte-gated organic transistors offer low bias operation facilitated by direct contact of the transistor channel with an electrolyte. Their operation mode is generally defined by the dimensionality of charge transport, where a field-effect transistor allows for electrostatic charge accumulation at the electrolyte/semiconductor interface, whereas an organic electrochemical transistor (OECT) facilitates penetration of ions into the bulk of the channel, considered a slow process, leading to volumetric doping and electronic transport. Conducting polymer OECTs allow for fast switching and high currents through incorporation of excess, hygroscopic ionic phases, but operate in depletion mode. Here, we show that the use of glycolated side chains on a thiophene backbone can result in accumulation mode OECTs with high currents, transconductance, and sharp subthreshold switching, while maintaining fast switching speeds. Compared with alkylated analogs of the same backbone, the triethylene glycol side chains shift the mode of operation of aqueous electrolyte-gated transistors from interfacial to bulk doping/transport and show complete and reversible electrochromism and high volumetric capacitance at low operating biases. We propose that the glycol side chains facilitate hydration and ion penetration, without compromising electronic mobility, and suggest that this synthetic approach can be used to guide the design of organic mixed conductors.

scholarly journals Synthesis of 1,2-disubstituted benzimidazoles using an aza-Wittig-equivalent process

RSC Advances ◽  
2017 ◽  
Vol 7 (70) ◽  
pp. 44421-44425
Author(s):  
Yuan Chen ◽  
Fanghui Xu ◽  
Zhihua Sun
Keyword(s):  
Synthetic Approach ◽  
Reaction Conditions

Based on an aza-Wittig-equivalent process, a novel synthetic approach for 1,2-disubstituted benzimidazoles has been successfully designed, which provides mild reaction conditions and excellent yields.

Oleate-modified hyaluronan: Controlling the number and distribution of side chains by varying the reaction conditions

2021 ◽  
pp. 118197
Author(s):  
Ondřej Štrympl ◽  
Jiří Vohlídal ◽  
Martina Hermannová ◽  
Mauricio Maldonado-Domínguez ◽  
Martina Brandejsová ◽  
...  
Keyword(s):  
Side Chains ◽  
Reaction Conditions
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