scholarly journals Controlled Synthesis of Linear Polyamidoamino Acids

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1324 ◽  
Author(s):  
Federica Ferruti ◽  
Jenny Alongi ◽  
Amedea Manfredi ◽  
Elisabetta Ranucci ◽  
Paolo Ferruti
Keyword(s):  
Amino Acids ◽  
Building Blocks ◽  
Synthetic Polymers ◽  
Polymerization Process ◽  
Random Copolymers ◽  
Controlled Synthesis ◽  
Molecular Weights ◽  
Synthetic Procedure ◽  
Low Solubility ◽  
By Products

Polyamidoamino acids (PAACs) are synthetic polymers prepared by the polyaddition of bisacrylamides with natural α-amino acids, which in the process maintain both their chirality and their amphoteric nature. This polymerization process is slow, but has the merits of taking place in water and of neither involving protection/de-protection steps nor releasing by-products. However, it leads to polydisperse polymers and, using α-amino acids mixtures, random copolymers. This paper presents a step-by-step polyaddition process leading to homo- and copolymeric PAACs with controlled sequences and controlled molecular weights. It exploits the much different rates of the two Michael addition steps of NH2 of α-amino acids with acrylamides, and the low solubility in organic solvents of the α-amino acid addition products. As a proof of principle, the controlled synthesis of the PAAC from l-arginine and N,N′-methylenebisacrylamide was performed up to a monodisperse product with 11 monomeric units and molecular weight 1840. This synthetic procedure was also tested with l-alanine. All intermediates were isolated and characterized. Noticeably, all of them were α,ω-difunctionalized with either acrylamides or sec-amines and were, in fact, building blocks with potential for preparing complex macromolecular architectures. In a first instance, copolymers with controlled sequences of amidoamine- and amidoamino acid units were prepared.

scholarly journals Generation and application of Cu-bound alkyl nitrene for the catalyst-controlled synthesis of cyclic β-amino acids

2021 ◽  
Author(s):  
Raj K Tak ◽  
Fuyuki Amemiya ◽  
Hidetoshi Noda ◽  
Masakatsu Shibasaki
Keyword(s):  
Amino Acids ◽  
Medicinal Chemistry ◽  
Building Blocks ◽  
Controlled Synthesis ◽  
New Methods

The advent of saturated N-heterocycles as valuable building blocks in medicinal chemistry has led to the development of new methods to construct such nitrogen-containing cyclic frameworks. Despite the apparent strategic...

Experimental Observations About Improving the Properties of Collagen Extracts for Applications in Agriculture

2018 ◽  
Vol 69 (2) ◽  
pp. 379-385 ◽  
Author(s):  
Mihaela Doina Niculescu ◽  
Carmen Gaidau ◽  
Doru Gabriel Epure ◽  
Mihai Gidea
Keyword(s):  
Amino Acids ◽  
Atmospheric Pressure ◽  
Free Amino Acids ◽  
Plant Nutrition ◽  
Free Amino ◽  
Organic Nitrogen ◽  
Molecular Weights ◽  
Collagen Hydrolysates ◽  
By Products ◽  
Plant Treatment

This study highlights the fact that some properties of collagen extracts obtained by thermo-chemical and enzymatic processes from leather by-products may be modified and corrected during concentration or filtration operations in order to achieve performance specific to applications in agriculture (seed, soil and plant treatment in various phases of vegetation), as an alternative to treatment using synthetic substances. Concentration of collagen hydrolysates at atmospheric pressure leads to polydispersions with high molecular weights favourable to structuring collagen films, that will gradually release organic nitrogen, for plant nutrition in various vegetation stages. Concentration under vacuum results in polydispersions with low molecular weights, richer in free amino acids and oligopeptides that can penetrate cell membranes. Also, filtration under vacuum using low-porosity membranes (0.45-0.80 mm) determines deagglomeration, selection and concentration of particles with sizes ranging from 1 to 10 nm and from 10 to 100 nm, characteristic to amino acids and dipeptides, into filtrates.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

scholarly journals Wine By-Products as Raw Materials for the Production of Biopolymers and of Natural Reinforcing Fillers: A Critical Review

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 381
Author(s):  
Alessandro Nanni ◽  
Mariafederica Parisi ◽  
Martino Colonna
Keyword(s):  
Critical Review ◽  
Raw Materials ◽  
Green Revolution ◽  
Building Blocks ◽  
Poly Lactic Acid ◽  
Butylene Succinate ◽  
Reinforcing Fillers ◽  
Plastic Industry ◽  
Review Reports ◽  
By Products

The plastic industry is today facing a green revolution; however, biopolymers, produced in low amounts, expensive, and food competitive do not represent an efficient solution. The use of wine waste as second-generation feedstock for the synthesis of polymer building blocks or as reinforcing fillers could represent a solution to reduce biopolymer costs and to boost the biopolymer presence in the market. The present critical review reports the state of the art of the scientific studies concerning the use of wine by-products as substrate for the synthesis of polymer building blocks and as reinforcing fillers for polymers. The review has been mainly focused on the most used bio-based and biodegradable polymers present in the market (i.e., poly(lactic acid), poly(butylene succinate), and poly(hydroxyalkanoates)). The results present in the literature have been reviewed and elaborated in order to suggest new possibilities of development based on the chemical and physical characteristics of wine by-products.

scholarly journals Chiroptical activity of hydroxycarboxylic acids with implications for the origin of biological homochirality

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Jana Bocková ◽  
Nykola C. Jones ◽  
Uwe J. Meierhenrich ◽  
Søren V. Hoffmann ◽  
Cornelia Meinert
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Organic Molecules ◽  
Building Blocks ◽  
Aliphatic Chain ◽  
Monocarboxylic Acids ◽  
Hydroxycarboxylic Acids ◽  
Polarised Light ◽  
Suitable Target ◽  
Anisotropy Spectra

AbstractCircularly polarised light (CPL) interacting with interstellar organic molecules might have imparted chiral bias and hence preluded prebiotic evolution of biomolecular homochirality. The l-enrichment of extra-terrestrial amino acids in meteorites, as opposed to no detectable excess in monocarboxylic acids and amines, has previously been attributed to their intrinsic interaction with stellar CPL revealed by substantial differences in their chiroptical signals. Recent analyses of meteoritic hydroxycarboxylic acids (HCAs) – potential co-building blocks of ancestral proto-peptides – indicated a chiral bias toward the l-enantiomer of lactic acid. Here we report on novel anisotropy spectra of several HCAs using a synchrotron radiation electronic circular dichroism spectrophotometer to support the re-evaluation of chiral biomarkers of extra-terrestrial origin in the context of absolute photochirogenesis. We found that irradiation by CPL which would yield l-excess in amino acids would also yield l-excess in aliphatic chain HCAs, including lactic acid and mandelic acid, in the examined conditions. Only tartaric acid would show “unnatural” d-enrichment, which makes it a suitable target compound for further assessing the relevance of the CPL scenario.

scholarly journals Lipase Catalyzed Synthesis of Enantiopure Precursors and Derivatives for β-Blockers Practolol, Pindolol and Carteolol

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 503
Author(s):  
Morten Gundersen ◽  
Guro Austli ◽  
Sigrid Løvland ◽  
Mari Hansen ◽  
Mari Rødseth ◽  
...  
Keyword(s):  
Building Block ◽  
Kinetic Resolution ◽  
Enantiomeric Excess ◽  
Catalytic Amount ◽  
Building Blocks ◽  
Β Blocker ◽  
Β Blockers ◽  
Optical Rotations ◽  
Reported Data ◽  
By Products

Sustainable methods for producing enantiopure drugs have been developed. Chlorohydrins as building blocks for several β-blockers have been synthesized in high enantiomeric purity by chemo-enzymatic methods. The yield of the chlorohydrins increased by the use of catalytic amount of base. The reason for this was found to be the reduced formation of the dimeric by-products compared to the use of higher concentration of the base. An overall reduction of reagents and reaction time was also obtained compared to our previously reported data of similar compounds. The enantiomers of the chlorohydrin building blocks were obtained by kinetic resolution of the racemate in transesterification reactions catalyzed by Candida antarctica Lipase B (CALB). Optical rotations confirmed the absolute configuration of the enantiopure drugs. The β-blocker (S)-practolol ((S)-N-(4-(2-hydroxy-3-(isopropylamino)propoxy)phenyl)acetamide) was synthesized with 96% enantiomeric excess (ee) from the chlorohydrin (R)-N-(4-(3-chloro-2 hydroxypropoxy)phenyl)acetamide, which was produced in 97% ee and with 27% yield. Racemic building block 1-((1H-indol-4-yl)oxy)-3-chloropropan-2-ol for the β-blocker pindolol was produced in 53% yield and (R)-1-((1H-indol-4-yl)oxy)-3-chloropropan-2-ol was produced in 92% ee. The chlorohydrin 7-(3-chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one, a building block for a derivative of carteolol was produced in 77% yield. (R)-7-(3-Chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one was obtained in 96% ee. The S-enantiomer of this carteolol derivative was produced in 97% ee in 87% yield. Racemic building block 5-(3-chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one, building block for the drug carteolol, was also produced in 53% yield, with 96% ee of the R-chlorohydrin (R)-5-(3-chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one. (S)-Carteolol was produced in 96% ee with low yield, which easily can be improved.

scholarly journals Synthesis, Characterization and Evaluation of Peptide Nanostructures for Biomedical Applications

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4587
Author(s):  
Fanny d’Orlyé ◽  
Laura Trapiella-Alfonso ◽  
Camille Lescot ◽  
Marie Pinvidic ◽  
Bich-Thuy Doan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Biomedical Applications ◽  
Chemical Reactivity ◽  
Physical Stability ◽  
Chemical Properties ◽  
Building Blocks ◽  
Imaging Probes ◽  
Therapeutic Molecules

There is a challenging need for the development of new alternative nanostructures that can allow the coupling and/or encapsulation of therapeutic/diagnostic molecules while reducing their toxicity and improving their circulation and in-vivo targeting. Among the new materials using natural building blocks, peptides have attracted significant interest because of their simple structure, relative chemical and physical stability, diversity of sequences and forms, their easy functionalization with (bio)molecules and the possibility of synthesizing them in large quantities. A number of them have the ability to self-assemble into nanotubes, -spheres, -vesicles or -rods under mild conditions, which opens up new applications in biology and nanomedicine due to their intrinsic biocompatibility and biodegradability as well as their surface chemical reactivity via amino- and carboxyl groups. In order to obtain nanostructures suitable for biomedical applications, the structure, size, shape and surface chemistry of these nanoplatforms must be optimized. These properties depend directly on the nature and sequence of the amino acids that constitute them. It is therefore essential to control the order in which the amino acids are introduced during the synthesis of short peptide chains and to evaluate their in-vitro and in-vivo physico-chemical properties before testing them for biomedical applications. This review therefore focuses on the synthesis, functionalization and characterization of peptide sequences that can self-assemble to form nanostructures. The synthesis in batch or with new continuous flow and microflow techniques will be described and compared in terms of amino acids sequence, purification processes, functionalization or encapsulation of targeting ligands, imaging probes as well as therapeutic molecules. Their chemical and biological characterization will be presented to evaluate their purity, toxicity, biocompatibility and biodistribution, and some therapeutic properties in vitro and in vivo. Finally, their main applications in the biomedical field will be presented so as to highlight their importance and advantages over classical nanostructures.

scholarly journals A bicyclic S-adenosylmethionine regeneration system applicable with different nucleosides or nucleotides as cofactor building blocks

2021 ◽  
Author(s):  
Désirée Popadić ◽  
Dipali Mhaindarkar ◽  
Mike H. N. Dang Thai ◽  
Helen C. Hailes ◽  
Silja Mordhorst ◽  
...  
Keyword(s):  
Building Blocks ◽  
Regeneration System ◽  
Methyl Donor ◽  
By Products

The polyphosphate-driven bicyclic S-adenosylmethionine (SAM) regeneration system uses S-methylmethionine as a ‘2-in-1’ methyl donor without producing by-products and can be run with SAM nucleobase analogues such as S-cytidyl- and S-inosylmethionine.

scholarly journals Synthesis of π-Conjugated Polymers Containing Benzotriazole Units via Palladium-Catalyzed Direct C-H Cross-Coupling Polycondensation for OLEDs Applications

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 254
Author(s):  
Dong Han ◽  
Jingwen Li ◽  
Qiang Zhang ◽  
Zewang He ◽  
Zhiwei Wu ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Quantum Efficiency ◽  
Cross Coupling ◽  
Building Blocks ◽  
Gravimetric Analysis ◽  
19F Nmr Spectra ◽  
Light Emitting ◽  
Molecular Weights ◽  
Palladium Catalyzed ◽  
Red Luminescence

Four D-π-A conjugated polymers, namely P1–P4, which contain benzotriazole building blocks in their backbone as acceptor, are synthesized via palladium-catalyzed direct C-H cross-coupling polycondensation of 5,6-difluorobenzotriazole with different thiophene derivatives, including 3-octylthiophene, 2,2’-bithiophene, thieno[3,4-b][1,4]dioxine, and 4,4-dioctyl-4H-silolo-[3,2-b:4,5-b’]dithiophene as donor units, respectively. Taking the polymer P1 as an example, the chemical structure of the polymer is demonstrated by 1H and 19F NMR spectra. The optical, electrochemical, and thermal properties of these polymers are assessed by UV–vis absorption and fluorescence spectroscopy, cyclic voltammetry (CV), and thermal gravimetric analysis (TGA), respectively. DFT simulations of all polymers are also performed to understand their physicochemical properties. Furthermore, P1 and P2, which have relatively higher molecular weights and better fluorescent quantum efficiency than those of P3 and P4, are utilized as lighting emitters for organic light-emitting diodes (OLEDs), affording promising green and red luminescence with 0.07% and 0.14% of maximum external quantum efficiency, respectively, based on a device with an architecture of ITO/PEDOT:PSS/PTAA/the polymer emitting layer/TPBi/LiF/Al.

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