Amide bonds meet flow chemistry: a journey into methodologies and sustainable evolution

A scalable access to functionalized 1,1’- and 1,2-ferrocenyl azides has been realized in flow. By halogen‒lithium exchange of ferrocenyl halides and subsequent reaction with tosyl azide, a variety of functionalized ferrocenyl azides was obtained in high yields. To allow a scalable preparation of these potentially explosive compounds, an efficient flow protocol was developed accelerating the reaction time to minutes and circumventing accumulation of potentially hazardous intermediates. Switching from homogeneous to triphasic flow amidst process was key for handling a heterogeneous reaction mixture formed after a heated reactor section. The corresponding and synthetically versatile ferrocenyl amines were then prepared by a reliable reduction process.

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Room Temperature Flow Electrochemistry as a Means of Retaining the “Memory of Chirality” via Hofer Moest Type Reaction

10.26434/chemrxiv.11516967.v2 ◽

2020 ◽

Author(s):

Tomas Hardwick ◽

Rossana Cicala ◽

Nisar Ahmed

Keyword(s):

Continuous Flow ◽

Room Temperature ◽

Biological Activities ◽

Supporting Electrolyte ◽

Enantiomeric Excess ◽

Flow Chemistry ◽

Batch Processes ◽

Enabling Technology ◽

Chiral Compounds ◽

Memory Of Chirality

Many chiral compounds have become of great interest to the pharmaceutical industry as they possess various biological activities. Concurrently, the concept of “memory of chirality” has been proven as a powerful tool in asymmetric synthesis, while flow chemistry has begun its rise as a new enabling technology to add to the ever increasing arsenal of techniques available to the modern day chemist. Here, we have employed a new simple electrochemical microreactor design to oxidise an L-proline derivative at room temperature in continuous flow. Flow performed in microreactors offers up a number of benefits allowing reactions to be performed in a more convenient and safer manner, and even allow electrochemical reactions to take place without a supporting electrolyte due to a very short interelectrode distance. By the comparison of electrochemical oxidations in batch and flow we have found that continuous flow is able to outperform its batch counterpart, producing a good yield (71%) and a better enantiomeric excess (64%) than batch with a 98% conversion. We have, therefore, provided evidence that continuous flow chemistry has the potential to act as a new enabling technology to replace some aspects of conventional batch processes.

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Flow Chemistry Controls Both Self-Assembly and the Entrapped Oscillatory Cargo in Belousov-Zhabotinsky Driven Polymerization-Induced Self-Assembly

10.26434/chemrxiv.7895891 ◽

2019 ◽

Author(s):

Liman Hou ◽

Marta Dueñas-Diez ◽

Rohit Srivastava ◽

Juan Perez-Mercader

Keyword(s):

Self Assembly ◽

Flow Chemistry ◽

Batch Reactors ◽

Equilibrium Conditions ◽

One Pot ◽

Bz Reaction ◽

Polymer Vesicles ◽

Simultaneous Control ◽

Novel Method ◽

Continuously Stirred Tank Reactor

Belousov-Zhabotinsky (B-Z) reaction driven polymerization-induced self-assembly (PISA), or B-Z PISA, is a novel method for the autonomous one-pot synthesis of polymer vesicles from a macroCTA (macro chain transfer agent) and monomer solution (“soup”) containing the above and the BZ reaction components. In it, the polymerization is driven (and controlled) by periodically generated radicals generated in the oscillations of the B-Z reaction. These are inhibitor/activator radicals for the polymerization. Until now B-Z PISA has only been carried out in batch reactors. In this manuscript we present the results of running the system using a continuously stirred tank reactor (CSTR) configuration which offers some interesting advantages.Indeed, by controlling the CSTR parameters we achieve reproducible and simultaneous control of the PISA process and of the properties of the oscillatory cargo encapsulated in the resulting vesicles. Furthermore, the use of flow chemistry enables a more precise morphology control and chemical cargo tuning. Finally, in the context of biomimetic applications a CSTR operation mimics more closely the open non-equilibrium conditions of living systems and their surrounding environments.

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Faculty Opinions recommendation of Synthesis of acetal protected building blocks using flow chemistry with flow I.R. analysis: preparation of butane-2,3-diacetal tartrates.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.2353960.1981060 ◽

2010 ◽

Author(s):

Stevan Djuric ◽

Christina Thompson

Keyword(s):

Flow Chemistry ◽

Building Blocks

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Continuous Synthesis of Nanocrystals via Flow Chemistry Technology

Small ◽

10.1002/smll.202104166 ◽

2021 ◽

Vol 17 (33) ◽

pp. 2104166

Author(s):

Jinsong Sui ◽

Junyu Yan ◽

Di Liu ◽

Kai Wang ◽

Guangsheng Luo

Keyword(s):

Flow Chemistry ◽

Continuous Synthesis

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Synthesis and Characterization of a Bioconjugate Based on Oleic Acid and L-Cysteine

Polymers ◽

10.3390/polym13111791 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1791

Author(s):

Marco Vizcarra-Pacheco ◽

María Ley-Flores ◽

Ana Mizrahim Matrecitos-Burruel ◽

Ricardo López-Esparza ◽

Daniel Fernández-Quiroz ◽

...

Keyword(s):

Oleic Acid ◽

Materials Science ◽

Critical Micellar Concentration ◽

Synthesis And Characterization ◽

New Materials ◽

Visible Spectroscopy ◽

Amide Bonds ◽

Transmission Electron ◽

Self Assembled

One of the main challenges facing materials science today is the synthesis of new biodegradable and biocompatible materials capable of improving existing ones. This work focused on the synthesis of new biomaterials from the bioconjugation of oleic acid with L-cysteine using carbodiimide. The resulting reaction leads to amide bonds between the carboxylic acid of oleic acid and the primary amine of L-cysteine. The formation of the bioconjugate was corroborated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and nuclear magnetic resonance (NMR). In these techniques, the development of new materials with marked differences with the precursors was confirmed. Furthermore, NMR has elucidated a surfactant structure, with a hydrophilic part and a hydrophobic section. Ultraviolet-visible spectroscopy (UV-Vis) was used to determine the critical micellar concentration (CMC) of the bioconjugate. Subsequently, light diffraction (DLS) was used to analyze the size of the resulting self-assembled structures. Finally, transmission electron microscopy (TEM) was obtained, where the shape and size of the self-assembled structures were appreciated.

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Preparation of Soluble POSS-Linking Polyamide and Its Application in Antifogging Films

Materials ◽

10.3390/ma14123178 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3178

Author(s):

Tomoya Kozuma ◽

Aki Mihata ◽

Yoshiro Kaneko

Keyword(s):

Water Vapor ◽

Heat Treating ◽

Scratch Test ◽

29Si Nmr ◽

Polar Solvents ◽

Amide Bonds ◽

Ethylcarbodiimide Hydrochloride ◽

Ft Ir ◽

Oligomeric Silsesquioxane ◽

Condensing Agents

In this study, we prepared a polyhedral oligomeric silsesquioxane (POSS)-linking polyamide (POSS polyamide) by a polycondensation of ammonium-functionalized POSS (POSS-A) and carboxyl-functionalized POSS (POSS-C) in dehydrated dimethyl sulfoxide (DMSO) using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) as condensing agents. The obtained POSS polyamide was soluble in various highly polar solvents, and it could form a self-standing film. FT-IR, 1H NMR, and 29Si NMR analyses showed that POSS polyamide is a polymer in which POSS-A and POSS-C are linked almost linearly by amide bonds. Furthermore, the cast film obtained by heat-treating the polymer at 150 °C for 30 min exhibited excellent transparency and hard-coating (pencil scratch test: 5H) and antifogging properties (evaluation by water vapor exposure).

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1,2,3-Triazoles as Biomimetics in Peptide Science

Molecules ◽

10.3390/molecules26102937 ◽

2021 ◽

Vol 26 (10) ◽

pp. 2937

Author(s):

Naima Agouram ◽

El Mestafa El Hadrami ◽

Abdeslem Bentama

Keyword(s):

Enzymatic Degradation ◽

Triazole Ring ◽

Biologically Active ◽

Amide Bond ◽

Biologically Relevant ◽

Amide Bonds ◽

Natural Peptides ◽

Mimicking Peptides ◽

Chemical Mediators

Natural peptides are an important class of chemical mediators, essential for most vital processes. What limits the potential of the use of peptides as drugs is their low bioavailability and enzymatic degradation in vivo. To overcome this limitation, the development of new molecules mimicking peptides is of great importance for the development of new biologically active molecules. Therefore, replacing the amide bond in a peptide with a heterocyclic bioisostere, such as the 1,2,3-triazole ring, can be considered an effective solution for the synthesis of biologically relevant peptidomimetics. These 1,2,3-triazoles may have an interesting biological activity, because they behave as rigid link units, which can mimic the electronic properties of amide bonds and show bioisosteric effects. Additionally, triazole can be used as a linker moiety to link peptides to other functional groups.

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Highly absorbent hydrogels comprised from interpenetrated networks of alginate–polyurethane for biomedical applications

Journal of Materials Science Materials in Medicine ◽

10.1007/s10856-021-06544-4 ◽

2021 ◽

Vol 32 (6) ◽

Author(s):

Jesús A. Claudio-Rizo ◽

Nallely Escobedo-Estrada ◽

Sara L. Carrillo-Cortes ◽

Denis A. Cabrera-Munguía ◽

Tirso E. Flores-Guía ◽

...

Keyword(s):

Biomedical Applications ◽

Degradation Rate ◽

High Capacity ◽

Hydrolytic Degradation ◽

Absorption Capacity ◽

Amide Bonds ◽

E Coli ◽

Swelling Capacity ◽

And Storage ◽

Potential Area

AbstractDeveloping new approaches to improve the swelling, degradation rate, and mechanical properties of alginate hydrogels without compromising their biocompatibility for biomedical applications represents a potential area of research. In this work, the generation of interpenetrated networks (IPN) comprised from alginate–polyurethane in an aqueous medium is proposed to design hydrogels with tailored properties for biomedical applications. Aqueous polyurethane (PU) dispersions can crosslink and interpenetrate alginate chains, forming amide bonds that allow the structure and water absorption capacity of these novel hydrogels to be regulated. In this sense, this work focuses on studying the relation of the PU concentration on the properties of these hydrogels. The results indicate that the crosslinking of the alginate with PU generates IPN hydrogels with a crystalline structure characterized by a homogeneous smooth surface with high capacity to absorb water, tailoring the degradation rate, thermal decomposition, and storage module, not altering the native biocompatibility of alginate, providing character to inhibit the growth of E. coli and increasing also its hemocompatibility. The IPN hydrogels that include 20 wt.% of PU exhibit a reticulation index of 46 ± 4%, swelling capacity of 545 ± 13% at 7 days of incubation at physiological pH, resistance to both acidic and neutral hydrolytic degradation, mechanical improvement of 91 ± 1%, and no cytotoxicity for monocytes and fibroblasts growing for up to 72 h of incubation. These results indicate that these novel hydrogels can be used for successful biomedical applications in the design of wound healing dressings.

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