scholarly journals The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

2020 ◽  
Vol 16 ◽  
pp. 2272-2281
Author(s):  
Patrizia Andreozzi ◽  
Lorenza Tamberi ◽  
Elisamaria Tasca ◽  
Gina Elena Giacomazzo ◽  
Marta Martinez ◽  
...  
Keyword(s):  
Reaction Time ◽  
Ball Milling ◽  
Hydrophobic Interactions ◽  
Phenylboronic Acid ◽  
Synthetic Route ◽  
Complex Molecules ◽  
Pyrene Fluorescence ◽  
Solvent Free Conditions ◽  
Boron Dipyrromethene ◽  
Conventional Solution

Mechanochemistry is an emerging and reliable alternative to conventional solution (batch) synthesis of complex molecules under green and solvent-free conditions. In this regard, we report here on the conjugation of a dextran polysaccharide with a fluorescent probe, a phenylboronic acid (PBA)-functionalized boron dipyrromethene (BODIPY) applying the ball milling approach. The ball milling formation of boron esters between PBA BODIPY and dextran proved to be more efficient in terms of reaction time, amount of reactants, and labelling degree compared to the corresponding solution-based synthetic route. PBA-BODIPY dextran assembles into nanoparticles of around 200 nm by hydrophobic interactions. The resulting PBA-BODIPY dextran nanoparticles retain an apolar interior as proved by pyrene fluorescence, suitable for the encapsulation of hydrophobic drugs with high biocompatibility while remaining fluorescent.

Visible Light-Mediated Oxidative Debenzylation

2020 ◽  
Author(s):  
Cristian Cavedon ◽  
Eric T. Sletten ◽  
Amiera Madani ◽  
Olaf Niemeyer ◽  
Peter H. Seeberger ◽  
...  
Keyword(s):  
Reaction Time ◽  
Visible Light ◽  
Functional Groups ◽  
Continuous Flow ◽  
Protecting Groups ◽  
Benzyl Ether ◽  
Complex Molecules ◽  
Protective Groups ◽  
Benzyl Ethers ◽  
Harsh Conditions

Protecting groups are key in the synthesis of complex molecules such as carbohydrates to distinguish functional groups of similar reactivity. The harsh conditions required to cleave stable benzyl ether protective groups are not compatible with many other protective and functional groups. The mild, visible light-mediated debenzylation disclosed here renders benzyl ethers orthogonal protective groups. Key to success is the use of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as stoichiometric or catalytic photooxidant such that benzyl ethers can be cleaved in the presence of azides, alkenes, and alkynes. The reaction time for this transformation can be reduced from hours to minutes in continuous flow. <br>

One-Pot, Regioselective Synthesis of Homopropargyl Alcohols using Propargyl Bromide and Carbonyl Compound by the Mg-mediated Reaction under Solvent-free Conditions

2020 ◽  
Vol 17 (6) ◽  
pp. 438-442
Author(s):  
Xiaofang Ma ◽  
Shunxi Li ◽  
Samrat Devaramani ◽  
Guohu Zhao ◽  
Daqian Xu
Keyword(s):  
Reaction Time ◽  
Organic Synthesis ◽  
Carbonyl Compounds ◽  
Solvent Free ◽  
Propargyl Bromide ◽  
Important Goal ◽  
One Pot ◽  
Short Reaction Time ◽  
Solvent Free Conditions ◽  
Volatile Organic

The elimination of volatile organic solvents in organic synthesis is the most important goal in “Green” chemistry. We report a simple, efficient and facile method for the addition of progargyl bromide to carbonyl compounds using Mg metal as a mediator under solvent-free conditions which could regioselectively generate homopropargyl alcohols efficiently in good to excellent yields. The procedure has advantages such as short reaction time, operationally simple, excellent product yields, high regioselectivity and organic solvent-free.

scholarly journals Mechanochemical synthesis of poly(trimethylene carbonate)s: an example of rate acceleration

2019 ◽  
Vol 15 ◽  
pp. 963-970 ◽  
Author(s):  
Sora Park ◽  
Jeung Gon Kim
Keyword(s):  
Ball Milling ◽  
Mechanochemical Synthesis ◽  
Polymeric Materials ◽  
Solvent Free ◽  
Energy Output ◽  
Polymerization Temperature ◽  
Mechanical Degradation ◽  
Trimethylene Carbonate ◽  
Rate Acceleration ◽  
Conventional Solution

Mechanochemical polymerization is a rapidly growing area and a number of polymeric materials can now be obtained through green mechanochemical synthesis. In addition to the general merits of mechanochemistry, such as being solvent-free and resulting in high conversions, we herein explore rate acceleration under ball-milling conditions while the conventional solution-state synthesis suffer from low reactivity. The solvent-free mechanochemical polymerization of trimethylene carbonate using the organocatalysts 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) are examined herein. The polymerizations under ball-milling conditions exhibited significant rate enhancements compared to polymerizations in solution. A number of milling parameters were evaluated for the ball-milling polymerization. Temperature increases due to ball collisions and exothermic energy output did not affect the polymerization rate significantly and the initial mixing speed was important for chain-length control. Liquid-assisted grinding was applied for the synthesis of high molecular weight polymers, but it failed to protect the polymer chain from mechanical degradation.

Polymorphism control in the mechanochemical and solution-based synthesis of a thermochromic Schiff base

CrystEngComm ◽  
2015 ◽  
Vol 17 (41) ◽  
pp. 7870-7877 ◽  
Author(s):  
Marija Zbačnik ◽  
Ivana Nogalo ◽  
Dominik Cinčić ◽  
Branko Kaitner
Keyword(s):  
Schiff Base ◽  
Solvent Free ◽  
Crystal Forms ◽  
Solvent Free Conditions ◽  
Conventional Solution

Three crystal forms of a thermochromic Schiff base derived fromo-vanillin and 3-aminoacetophenone were obtained by conventional solution-based methods. Two polymorphs out of three were synthesized by mechanochemical syntheses, under solvent-free conditions.

Isolation of Cellulose Nanofibers (CNFs) based on Ball-milling Technique Combined with Supercritical Carbon dioxide/ethanol Pretreatment

2021 ◽  
Author(s):  
Zhijun Hu ◽  
Xinyu Cao ◽  
Guanhong Huang ◽  
Daliang Guo
Keyword(s):  
Thermal Stability ◽  
Reaction Time ◽  
Ball Milling ◽  
High Efficiency ◽  
Cellulose Nanofibers ◽  
Sem Images ◽  
Tempo Oxidation ◽  
Good Thermal Stability ◽  
Ethanol Pretreatment ◽  
Ball Milling Technique

Abstract Here, a new pretreatment method has been developed to produce CNFs from micro-fibrillated cellulose (MFC) by supercritical CO 2 pretreatment followed with ball-milling (SCB). MFC was obtained from cotton stalk by chemical purification.Experimental factors were controlled to enhance the properties of SCB-CNF, meanwhile a comparative study was conducted with the method of TEMPO oxidation and microfluid homogenization (TMH). Compared to TMH-CNF, the SCB-CNF has such advantages as Energy saving, high efficiency and environmental protection, indicating a wide application in heat-resistant materials, load materials and other fields. The solid yields of P-MFC after supercritical CO 2 pretreatment gradually decreased together with the temperature and the reaction time. Scanning electron microscope (SEM) images of the SCB-CNF and TMH-CNF show that the morphology of the SCB-CNF was basically acicular but that of the TMH-CNF was mainly soft fibrous. The SCB-CNF is smaller in width and shorter in length, and its size is between CNC and CNF. Thermal gravimetric results suggest that the thermal stability of the SCB-CNF was substantially higher than those of the TMH-CNF. XRD results indicate that the crystallinity showed an initial increasing trend and then declined with increasing temperature and reaction time, and the crystallinity value of SCB-CNF was larger than that of CNFs. The smaller SCB-CNF became rougher and had a larger surface area. High crystallinity make good thermal stability, short and coarse fiber, easier to disperse than CNF, less energy consumption for dispersion, better than 3D mesh. It can be widely used in polymer composites, reinforcing agents, membrane materials and other fields.

scholarly journals Synthesis of acylglycerol derivatives by mechanochemistry

2019 ◽  
Vol 15 ◽  
pp. 811-817 ◽  
Author(s):  
Karen J Ardila-Fierro ◽  
Andrij Pich ◽  
Marc Spehr ◽  
José G Hernández ◽  
Carsten Bolm
Keyword(s):  
Amino Acids ◽  
Ball Milling ◽  
Mechanochemical Synthesis ◽  
Building Blocks ◽  
Synthetic Route ◽  
Biologically Relevant ◽  
Nucleotides And Nucleosides

In recent times, many biologically relevant building blocks such as amino acids, peptides, saccharides, nucleotides and nucleosides, etc. have been prepared by mechanochemical synthesis. However, mechanosynthesis of lipids by ball milling techniques has remained essentially unexplored. In this work, a multistep synthetic route to access mono- and diacylglycerol derivatives by mechanochemistry has been realized, including the synthesis of diacylglycerol-coumarin conjugates.

scholarly journals An Efficient and Green Synthesis of Fluorine Containing Benzo[a]xanthen-11(12H)-ones and Evaluation of their Anticancer Activity

2020 ◽  
Vol 32 (4) ◽  
pp. 923-929
Author(s):  
J. Sumalatha ◽  
A. Sreedevi ◽  
C. Radha Rani
Keyword(s):  
Mass Spectrometry ◽  
Reaction Time ◽  
Anticancer Activity ◽  
Low Cost ◽  
The Other ◽  
Significant Activity ◽  
One Pot ◽  
Efficient Procedure ◽  
Solvent Free Conditions ◽  
One Pot Condensation

A facile and an efficient procedure has been developed by one-pot condensation of naphthalene-diols, fluoro substituted benzaldehydes and cyclic 1,3-dicarbonyl compounds for the synthesis of fluorine containing benzo[a]xanthen-11(12H)-ones under the catalyst and solvent-free conditions. All the synthesized compounds were characterized by IR, NMR (1H & 13C) and mass spectrometry. Several advantages offer the present approach, such as, shorter reaction time, low cost, anticipation of toxic solvents and catalyst, higher yield of products and durability of substrate range. On the other hand, anticancer activity was also performed for the title compounds which demonstrated a significant activity on selected cancer cell lines.

scholarly journals Simple Protocol for the Knoevenagel Condensation Under Solvent Free Conditions using Tungstophosphoric Acid as Catalyst

2019 ◽  
Vol 31 (10) ◽  
pp. 2181-2184
Author(s):  
Abdulrahman I. Alharthi
Keyword(s):  
Catalytic Activity ◽  
Reaction Time ◽  
Room Temperature ◽  
Model Compound ◽  
Knoevenagel Condensation ◽  
Maximum Yield ◽  
Tungstophosphoric Acid ◽  
Grinding Method ◽  
Solvent Free Conditions ◽  
Simple Protocol

The effect of calcination on the performance of tungstophosphoric acid for the product of Knoevenagel condensation was investigated. Substituted aldehydes and dimedone has been used in the presence of calcined tungstophosphoric acid as a heterogeneous catalyst using grinding method at room temperature. The results of reactions revealed that calcined tungstophosphoric acid has superior catalytic activity comparing to non-calcined catalyst in terms of yield and reaction time. Maximum yield of model compound was achieved by using 10 mol% of calcined catalyst in a reaction time that does not exceed 10 min, whereas the yield at same amount of non-calcined catalyst was 86 % in a reaction time of 35 min.

Rapid synthesis of homoallylic alcohol from aldehyde with allyltributylstannane under solvent-free conditions

2012 ◽  
Vol 90 (2) ◽  
pp. 167-172 ◽  
Author(s):  
Pranjal P. Bora ◽  
H. Atoholi Sema ◽  
Barisha Wahlang ◽  
Ghanashyam Bez
Keyword(s):  
Reaction Time ◽  
Phosphotungstic Acid ◽  
Catalytic Amount ◽  
Solvent Free ◽  
Reaction Conditions ◽  
Rapid Synthesis ◽  
Short Reaction Time ◽  
Solvent Free Conditions ◽  
Solvent Free Reaction

A catalytic amount (2 mol %) of phosphotungstic acid (PTA) is sufficient to synthesize homoallylic alcohol in excellent yields from aldehyde with allyltributylstannane upon grinding under solvent-free reaction conditions. Easy handling, very short reaction time, solvent-free reaction conditions, and aqueous workup free isolation protocol may make our method very useful for synthetic chemists.

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