Copper-catalyzed alkyne-azide cycloaddition for the functionalization of fullerene building blocks

2011 ◽  
Vol 84 (4) ◽  
pp. 1027-1037 ◽  
Author(s):  
Jean-François Nierengarten
Keyword(s):  
Chemical Transformation ◽  
Building Blocks ◽  
Reaction Conditions ◽  
Cuaac Reaction

In this paper, we report our ongoing progress in the preparation of fullerene-azide or fullerene-alkyne building blocks, allowing their further chemical transformation under the copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction conditions.

scholarly journals An eco-compatible strategy for the diversity-oriented synthesis of macrocycles exploiting carbohydrate-derived building blocks

2017 ◽  
Vol 13 ◽  
pp. 1106-1118 ◽  
Author(s):  
Sushil K Maurya ◽  
Rohit Rana
Keyword(s):  
Building Blocks ◽  
Ring Size ◽  
Macrocyclic Compounds ◽  
Reaction Conditions ◽  
Structural Class ◽  
Diversity Oriented Synthesis ◽  
Cuaac Reaction ◽  
Standard Reaction

An efficient, eco-compatible diversity-oriented synthesis (DOS) approach for the generation of library of sugar embedded macrocyclic compounds with various ring size containing 1,2,3-triazole has been developed. This concise strategy involves the iterative use of readily available sugar-derived alkyne/azide–alkene building blocks coupled through copper catalyzed azide–alkyne cycloaddition (CuAAC) reaction followed by pairing of the linear cyclo-adduct using greener reaction conditions. The eco-compatibility, mild reaction conditions, greener solvents, easy purification and avoidance of hazards and toxic solvents are advantages of this protocol to access this important structural class. The diversity of the macrocycles synthesized (in total we have synthesized 13 macrocycles) using a set of standard reaction protocols demonstrate the potential of the new eco-compatible approach for the macrocyclic library generation.

scholarly journals A Sustainable Improvement of ω-Bromoalkylphosphonates Synthesis to Access Novel KuQuinones

Organics ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 107-117
Author(s):  
Mattia Forchetta ◽  
Valeria Conte ◽  
Giulia Fiorani ◽  
Pierluca Galloni ◽  
Federica Sabuzi
Keyword(s):  
Metal Oxides ◽  
Phosphonic Acid ◽  
Organic Molecules ◽  
Building Blocks ◽  
Reaction Conditions ◽  
Phosphonic Acids ◽  
Sustainable Improvement ◽  
Phosphonate Esters ◽  
First Time ◽  
Complex Organic

Owing to the attractiveness of organic phosphonic acids and esters in the pharmacological field and in the functionalization of conductive metal-oxides, the research of effective synthetic protocols is pivotal. Among the others, ω-bromoalkylphosphonates are gaining particular attention because they are useful building blocks for the tailored functionalization of complex organic molecules. Hence, in this work, the optimization of Michaelis–Arbuzov reaction conditions for ω-bromoalkylphosphonates has been performed, to improve process sustainability while maintaining good yields. Synthesized ω-bromoalkylphosphonates have been successfully adopted for the synthesis of new KuQuinone phosphonate esters and, by hydrolysis, phosphonic acid KuQuinone derivatives have been obtained for the first time. Considering the high affinity with metal-oxides, KuQuinones bearing phosphonic acid terminal groups are promising candidates for biomedical and photo(electro)chemical applications.

scholarly journals Synthesis of new Cα-tetrasubstituted α-amino acids

2009 ◽  
Vol 5 ◽  
Author(s):  
Andreas A Grauer ◽  
Burkhard König
Keyword(s):  
Amino Acids ◽  
Secondary Structure ◽  
Aromatic Aldehydes ◽  
Building Blocks ◽  
Reaction Conditions ◽  
Peptide Backbone ◽  
Aliphatic Aldehydes ◽  
New Class ◽  
Cyclic Amino Acids

Cα-Tetrasubstituted α-amino acids are important building blocks for the synthesis of peptidemimetics with stabilized secondary structure, because of their ability to rigidify the peptide backbone. Recently our group reported a new class of cyclic Cα-tetrasubstituted tetrahydrofuran α-amino acids prepared from methionine and aromatic aldehydes. We now report the extension of this methodology to aliphatic aldehydes. Although such aldehydes are prone to give aldol products under the reaction conditions used, we were able to obtain the target cyclic amino acids in low to moderate yields and in some cases with good diastereoselectivity.

scholarly journals NaIO4/Br- as a mild system for the oxidation of 1-methyl-anthra-9,10-quinones

2015 ◽  
Author(s):  
Marcin Cybulski ◽  
Adam Formela ◽  
Katarzyna Sidoryk ◽  
Olga Michalak ◽  
Anna Rosa ◽  
...  
Keyword(s):  
High Pressure ◽  
Carboxylic Acids ◽  
Scale Up ◽  
Lithium Bromide ◽  
Cost Effective ◽  
Building Blocks ◽  
Multidrug Resistant ◽  
Resistant Cell ◽  
Direct Oxidation ◽  
Reaction Conditions

One of the anthraquinone classes comprises compounds with a carbonyl group. These natural or synthetic anthraquinones find their application as building blocks in the synthesis of the compounds with a biological activity. Recently, 4-substituted anthra-9,10-quinone-1-carboxylic acids (2) have been used as key intermediates in the synthesis of patented compounds (3) with anticancer activity against multidrug resistant cell lines. Although 2,7-dihydro-3H-dibenz[de,h]cinnolin-3,7-diones (3) were successfully synthetized in a small laboratory scale, several problems were observed during the preparation of their acid intermediates (2) in a multi-gram scale. The known methods for the preparation of 2 are based on the oxidation of the methyl group in anthra-9,10-quinones (1). The most common are: the oxidation with the diluted nitric acid under high pressure in a sealed tube at the temperature of 195-220 oC, the oxidation in nitrobenzene by passing chlorine gas through the reaction mixture at the temperature of 160-170 oC or in a presence of the fuming sulphuric acid. The mentioned methods require aggressive reagents and specific reaction conditions including high pressure and temperature. Thus, there was a need to find a new efficient, cost-effective and reproducible synthetic method of preparation of 2. While searching literature it was found that the direct oxidation of alkylarenes mediated by the sodium periodate/lithium bromide combination produces benzyl acetates throughout benzyl bromides in the acetic acid, or benzylic acids in the diluted inorganic acid. Based on these results we examined a variety of reaction conditions with or without the bromine source and the oxidizing anion. As a result, a novel procedure for the preparation of highly pure 4-substituted anthra-9,10-quinone-1-carboxylic acids (HPLC > 99.5%) using oxidizing anion/ brominating reagent system was developed. It enabled 2 isolation by the simple filtration of the reaction mixture and was applied in the scale-up of 2,7-dihydro-3H-dibenz[de,h]cinnolin-3,7-dione derivatives.

scholarly journals A novel three-component reaction between isocyanides, alcohols or thiols and elemental sulfur: a mild, catalyst-free approach towards O-thiocarbamates and dithiocarbamates

2019 ◽  
Vol 15 ◽  
pp. 1523-1533 ◽  
Author(s):  
András György Németh ◽  
György Miklós Keserű ◽  
Péter Ábrányi-Balogh
Keyword(s):  
Elemental Sulfur ◽  
Building Blocks ◽  
Reaction Conditions ◽  
One Pot ◽  
Catalyst Free ◽  
Synthetic Procedure ◽  
Three Component Reaction ◽  
Wide Range ◽  
Organic Chemist ◽  
The One

A new multicomponent reaction has been developed between isocyanides, sulfur and alcohols or thiols under mild reaction conditions to afford O-thiocarbamates and dithiocarbamates in moderate to good yields. The one-pot reaction cascade involves the formation of an isothiocyanate intermediate, thus a catalyst-free synthesis of isothiocyanates, as valuable building blocks from isocyanides and sulfur is proposed, as well. The synthetic procedure suits the demand of a modern organic chemist, as it tolerates a wide range of functional groups, it is atom economic and easily scalable.

scholarly journals Synthesis of a Fluorous-Tagged Hexasaccharide and Interaction with Growth Factors Using Sugar-Coated Microplates

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1591
Author(s):  
Susana Maza ◽  
José L. de Paz ◽  
Pedro M. Nieto
Keyword(s):  
Growth Factors ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Building Blocks ◽  
Strong Interactions ◽  
Fibroblast Growth ◽  
Reaction Conditions ◽  
Direct Binding ◽  
Acid Stable

Here, we report the synthesis of a sulfated, fully protected hexasaccharide as a glycosaminoglycan mimetic and the study of its interactions with different growth factors: midkine, basic fibroblast growth factor (FGF-2) and nerve growth factor (NGF). Following a fluorous-assisted approach, monosaccharide building blocks were successfully assembled and the target oligosaccharide was prepared in excellent yield. The use of more acid stable 4,6-O-silylidene protected glucosamine units was crucial for the efficiency of this strategy because harsh reaction conditions were needed in the glycosylations to avoid the formation of orthoester side products. Fluorescence polarization experiments demonstrated the strong interactions between the synthesized hexamer, and midkine and FGF-2. In addition, we have developed an alternative assay to analyse these molecular recognition events. The prepared oligosaccharide was non-covalently attached to a fluorous-functionalized microplate and the direct binding of the protein to the sugar-immobilized surface was measured, affording the corresponding KD,surf value.

scholarly journals Value-Added Bio-Chemicals Commodities from Catalytic Conversion of Biomass Derived Furan-Compounds

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 895
Author(s):  
Aitziber Iriondo ◽  
Ion Agirre ◽  
Nerea Viar ◽  
Jesús Requies
Keyword(s):  
Renewable Resources ◽  
Petrochemical Industry ◽  
Raw Materials ◽  
Value Added ◽  
Building Blocks ◽  
Reaction Conditions ◽  
Potential Market ◽  
Forestry Residues ◽  
Industry Needs ◽  
Near Future

The depletion of fossil resources in the near future and the need to decrease greenhouse gas emissions lead to the investigation of using alternative renewable resources as raw materials. One of the most promising options is the conversion of lignocellulosic biomass (like forestry residues) into bioenergy, biofuels and biochemicals. Among these products, the production of intermediate biochemicals has become an important goal since the petrochemical industry needs to find sustainable alternatives. In this way, the chemical industry competitiveness could be improved as bioproducts have a great potential market. Thus, the main objective of this review is to describe the production processes under study (reaction conditions, type of catalysts, solvents, etc.) of some promising intermediate biochemicals, such as; alcohols (1,2,6-hexanetriol, 1,6-hexanetriol and pentanediols (1,2 and 1,5-pentanediol)), maleic anhydride and 5-alkoxymethylfuran. These compounds can be produced using 5-hydroxymethylfurfural and/or furfural, which they both are considered one of the main biomass derived building blocks.

scholarly journals (S)-Pramipexole and Its Enantiomer, Dexpramipexole: A New Chemoenzymatic Synthesis and Crystallographic Investigation of Key Enantiomeric Intermediates

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 941
Author(s):  
Samuele Ciceri ◽  
Patrizia Ferraboschi ◽  
Paride Grisenti ◽  
Shahrzad Reza Elahi ◽  
Carlo Castellano ◽  
...  
Keyword(s):  
Single Crystal ◽  
Enantiomeric Excess ◽  
Three Dimensional ◽  
Building Blocks ◽  
Chemoenzymatic Synthesis ◽  
Racemic Mixture ◽  
Candida Antarctica Lipase ◽  
Crystallographic Investigation ◽  
Reaction Conditions ◽  
X Ray

A new chemoenzymatic method has been developed for the synthesis of (S)- and (R)-N-(6-hydroxy-4,5,6,7-tetrahydrobenzo[d]thiazol-2-yl) acetamide, two key synthons for the preparation of (S)-pramipexole, an anti-Parkinson drug, and its enantiomer dexpramipexole, which is currently under investigation for the treatment of eosinophil-associated disorders. These two building blocks have been obtained in good yields and high enantiomeric excess (30% and >98% ee for the R-enantiomer, and 31% and >99% ee for the S- one) through a careful optimization of the reaction conditions, starting from the corresponding racemic mixture and using two consecutive irreversible transesterifications, catalyzed by Candida antarctica lipase type A. Single crystal X-ray analysis has been carried out to unambiguously define the stereochemistry of the two enantiomers, and to explore in depth their three-dimensional features.

scholarly journals First Principles Micro-kinetic Model of Catalytic Non-oxidative Dehydrogenation of Ethane over Close-packed Metallic Facets

2019 ◽  
Author(s):  
Martin Hangaard Hansen ◽  
Jens K. Nørskov ◽  
Thomas Bligaard
Keyword(s):  
Kinetic Model ◽  
Oxidative Dehydrogenation ◽  
Reaction Network ◽  
Building Blocks ◽  
Light Olefins ◽  
Catalytic Dehydrogenation ◽  
Reaction Conditions ◽  
Model Code ◽  
Ethane Dehydrogenation ◽  
Oxidative Dehydrogenation Of Ethane

<div> <div> <p>Catalytic dehydrogenation of light alkanes may other more efficient routes to selectively producing light olefins, which are some of the most important chemical building blocks in the industry, in terms of scale. We present a descriptor based micro-kinetic model of the trends in selectivity and activity of non-oxidative dehydrogenation of ethane over close-packed metal facets and through varied reaction conditions. Our model predicts and explains the experimentally observed promotion effect on turnover rate from co-feeding hydrogen as an effect of the shifting equilibria in steady state. At low conversion reaction conditions over Pt, the path to ethene goes through ethane dehydrogenation to ethyl, CH 3 CH 2 *, then to ethene while the non-selective pathway to methane and deeply dehydrogenated species is predicted to go through dehydrogenation via CH 3 CH*. This implies that the desorption step of ethene is not the limiting step for selectivity and that geometric effects that stabilize CH 2 CH 2 * compared to CH 3 CH* are desirable properties of a better catalyst. Removing reactive bridge and 3-fold sites facilitates this, which may be achievable by sufficient concentrations of tin in platinum. The included model code furthermore provides a base for easy tuning and for expanding the study to other thermodynamic conditions, other facets, alloys or the reaction network to longer hydrocarbons or to oxidative pathways.</p> </div> </div>

Metal-Free Halogenation of N-Substituted Enaminoesters and Enaminones: A Facile Access to Functionalized α,α-Dihaloimines

Synthesis ◽  
2020 ◽  
Vol 52 (08) ◽  
pp. 1301-1314 ◽  
Author(s):  
Changfu Qiu ◽  
Heshui Yu ◽  
Chuanjiang Qiu ◽  
Fangyi Li ◽  
Tongchuan Suo ◽  
...  
Keyword(s):  
Transition Metals ◽  
Building Blocks ◽  
Synthetic Method ◽  
Safe Operation ◽  
Reaction Conditions ◽  
Metal Free ◽  
Synthetic Utility ◽  
General Method

An efficient and general method for the synthesis of functionalized α,α-dihaloimines via halogenation of N-substituted enaminoesters and enaminones is described. This reaction, in which both α,α-dihaloimines and mixed α,α-dihaloimines could be achieved in good to excellent yields, is believed to proceed via an α-monohalogenated enamine intermediate. This synthetic method features no use of transition metals, readily accessible substrates, mild reaction conditions, simple and safe operation, and gram scale synthesis. Furthermore, the synthetic utility of the products was demonstrated by their efficient transformations to further useful nitrogen-containing heterocycles and building blocks.

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