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.

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 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.

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 Synthesis and structure-physicochemical properties relationship of thiophene-substituted bis(5,4-d)thiazoles

2018 ◽  
Vol 17 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Zita Tokárová ◽  
Anna Biathová
Keyword(s):  
Physicochemical Properties ◽  
Organic Solvents ◽  
Synthetic Approach ◽  
Reaction Conditions ◽  
Relationship Of

Abstract Substituted thiophene-2-carbaldehydes 1a-dwere utilized in the synthesis of symmetrically substituted thiazolo[5,4-d]thiazoles 3a-d. Bis(5,4-d)thiazoles with thiophene core at the termini are the most employed in the chemistry of materials but exhibit insufficient solubility in majority of organic solvents with notable impact on the low yields of products. Accordingly, the synthetic approach towards 2,5-dithiophen- 2-yl-thiazolo[5,4-d]thiazole (3a) and its substituted derivatives 3b-d is discussed under the various reaction conditions. Appropriate structural characterisations are included with emphasis on relationship between structure and physicochemical properties highlighting the UV-Vis and fluorescence.

Synthesis of N,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED) and derivatives

1986 ◽  
Vol 64 (3) ◽  
pp. 449-456 ◽  
Author(s):  
Arthur E. Martell ◽  
Ramunas J. Motekaitis ◽  
Eric T. Clarke ◽  
J. J. Harrison
Keyword(s):  
Order Rate Constant ◽  
Synthetic Approach ◽  
Diacetic Acid ◽  
Substituted Phenols ◽  
Reaction Conditions ◽  
Complex Species ◽  
First Order ◽  
Synthetic Approaches ◽  
Hydrolysis Of ◽  
Selection Of

Two synthetic approaches for the synthesis of N,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED) and derivatives are reported. The first involves conversion of N,N′-di(2-hydroxybenzyl)ethylenediamine to the diamide HBEDDA via reaction with formaldehyde and HCN followed by hydrolysis. Analysis of the species distribution curves of the Cu(II) chelates of N,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED) and its diamide, HBEDDA, and of the nature of the coordination in each complex species formed, suggest the selection of the reaction conditions most favorable for the Cu(II)-catalyzed hydrolysis of HBEDDA to HBED. The rate of conversion was found to be low, and the reasons for these findings are described. Iron(III) catalysis of the conversion of HBEDDA to HBED was found to be rapid and complete with a pseudo-first-order rate constant of 3.1 × 10−3 s−1 at 25.0 °C. The results provide the final step of a new method for the synthesis of HBED. The second synthetic approach involves reaction of N,N′-ethylenediamine-diacetic acid (EDDA) with substituted phenols and formaldehyde. These approaches appear to be general for the synthesis of HBED and derivatives.

An Unexpected Coupling Reaction of 8-Quinolinolate at Elevated Temperature

2014 ◽  
Vol 67 (9) ◽  
pp. 1251 ◽  
Author(s):  
Glen B. Deacon ◽  
Craig M. Forsyth ◽  
Olga Gazukin ◽  
Peter C. Junk ◽  
Gerd Meyer ◽  
...  
Keyword(s):  
Rare Earth ◽  
Nickel Powder ◽  
Rare Earth Metals ◽  
Earth Metal ◽  
Coupling Reaction ◽  
Synthetic Approach ◽  
Cobalt Powder ◽  
Reaction Conditions ◽  
Homoleptic Complex ◽  
Smco5 Alloy

Reactions of 8-hydroxyquinoline (HOQ) with elemental rare-earth and transition metal combinations or alloys at 200–300°C yielded a variety of complexes, albeit in very low yields, including two structurally characterised homometallic complexes containing an unexpected biquinolinolate ligand. Reaction of HOQ with SmCo5 alloy gives rise to the complexes [SmCo2(OQ)7] (1), [Co4(OQ)4(BQ)2] (2), and [Sm3(OQ)5(BQ)2(H2O)] (3Sm), where BQ is 2,7′-biquinoline-8,8′-diolate, resulting from an unusual coupling reaction between two OQ/HOQ species at the 2 and 7′ positions. Complexes 1–3 and HOQ co-crystal 2·2HOQ were isolated as single crystals from separate reactions although formation of other products under the reaction conditions used was likely. Analogues of 3Sm with erbium and ytterbium were obtained using respective rare-earth metal filing in combination with nickel powder. Reaction involving cobalt powder only, without any rare-earth metals, yielded a homoleptic complex containing only the 8-quinolinolate ligand i.e. [Co4(OQ)8] (4). These results highlight the rewards, in terms of rich synthetic chemistry, and pitfalls, in terms of yield and isolation, of the pseudo-solid state synthetic approach using 8-quinolinolate ligands.

DBU-Promoted Formal [4+2] Annulation Reactions of o-Chloromethyl Anilines with Azlactones

Synthesis ◽  
2020 ◽  
Author(s):  
Jianfeng Xu ◽  
Haojie Ji ◽  
Chonglong He ◽  
Hongjie Gao ◽  
Weijun Fu
Keyword(s):  
Protecting Groups ◽  
Synthetic Approach ◽  
Quinone Methides ◽  
Reaction Conditions ◽  
Salient Features

AbstractAn efficient 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-mediated formal [4+2] annulation reaction of aza-ortho-quinone methides (aza-oQMs) (generated from o-chloromethyl anilines) with enolates (formed from azlactones) is disclosed, delivering biologically significant 3,4-dihydroquinolin-2(1H)-one derivatives in moderate to good yields. The salient features of this reaction include readily accessible starting materials, broad substrate scope, mild reaction conditions, removable protecting groups, and a scalable synthetic approach.

scholarly journals Vicinal difunctionalization of carbon–carbon double bond for the platform synthesis of trifluoroalkyl amines

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ferenc Béke ◽  
Ádám Mészáros ◽  
Ágnes Tóth ◽  
Bence Béla Botlik ◽  
Zoltán Novák
Keyword(s):  
Double Bond ◽  
Transition Metal ◽  
High Efficiency ◽  
Chemical Nature ◽  
Synthetic Approach ◽  
Selective Synthesis ◽  
Reaction Conditions ◽  
Metal Free ◽  
Amine Compounds ◽  
Broad Scale

AbstractRegioselective vicinal diamination of carbon–carbon double bonds with two different amines is a synthetic challenge under transition metal-free conditions, especially for the synthesis of trifluoromethylated amines. However, the synthesis of ethylene diamines and fluorinated amine compounds is demanded, especially in the pharmaceutical sector. Herein, we demonstrate that the controllable double nucleophilic functionalization of an activated alkene synthon, originated from a trifluoropropenyliodonium salt with two distinct nucleophiles, enables the selective synthesis of trifluoromethylated ethylene amines and diamines on broad scale with high efficiency under mild reaction conditions. Considering the chemical nature of the reactants, our synthetic approach brings forth an efficient methodology and provides versatile access to highly fluorinated amines.

Biochemical Synthesis and Unusual Conformational Switching of a Molecular Complex of Polyaniline and DNA

1999 ◽  
Vol 600 ◽  
Author(s):  
Ramaswamy Nagarajan ◽  
Sukant K. Tripathy ◽  
Jayant Kumar ◽  
Lynne A. Samuelson ◽  
Ferdinando F. Bruno
Keyword(s):  
Electrical Properties ◽  
Secondary Structure ◽  
Molecular Complex ◽  
Redox State ◽  
Water Soluble ◽  
Synthetic Approach ◽  
Redox Behavior ◽  
Conformational Switching ◽  
Reaction Conditions ◽  
Conducting Polyaniline

AbstractPolyaniline (Pani) is one of the most interesting conducting polymers because of its promising electrical properties and unique redox tunability. Recently a new template assisted, enzymatic synthetic approach has been developed which yields a water-soluble and conducting complex of polyaniline and the template used. The mild reaction conditions in this approach allow for the utilization of delicate biological systems as template materials, such as DNA. Here we report the extension of this enzymatic approach to the synthesis of Pani on a DNA matrix. DNA serves as a suitable template for complexation and formation of conducting polyaniline. The redox behavior of Pani induces reversible conformational change in the secondary structure of DNA. Circular dichroism results suggest that the secondary structure of the DNA may be reversibly switched through manipulation of the redox state of the polyaniline.

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