Unsaturated Acids Research Articles

Study on the Effect of Main Chain Molecular Structure on Adsorption, Dispersion, and Hydration of Polycarboxylate Superplasticizers.

Polycarboxylate ether (PCE) with different main chain structures was prepared by aqueous solution free radical polymerization using unsaturated acids containing sulfonic acid groups, acrylamide groups, and carboxyl groups and isoprenyl polyoxyethylene ether (IPEG). The molecular structure was characterized by infrared spectroscopy and gel chromatography, while adsorption, dispersion, and hydration properties were studied using a total organic carbon analyzer, rheometer, and isothermal microcalorimeter, respectively. The results show that the adsorption process of PCE on cement particles is spontaneous physical adsorption. The adsorption forces are mainly electrostatic interaction, and hydrogen bonding. The introduction of sulfonic acid groups and polycarboxylic acid groups reduces the initial adsorption amount of PCE but can accelerate the adsorption rate of PCE on cement and increase the adsorption amount at the adsorption equilibrium. The introduction of acrylamide groups in the PCE main chain is beneficial to the initial dispersion of PCE and can reduce the plastic viscosity of cement slurry. PCE can delay the hydration of cement. The introduction of acrylamide groups and dicarboxylic acid groups in the PCE main chain helps prolong the induction period of cement hydration, while the introduction of sulfonic acid groups is not conducive to its retarding effect.

Engineering the biological conversion of formate into crotonate in Cupriavidus necator

To advance the sustainability of the biobased economy, our society needs to develop novel bioprocesses based on truly renewable resources. The C1-molecule formate is increasingly proposed as carbon and energy source for microbial fermentations, as it can be efficiently generated electrochemically from CO2 and renewable energy. Yet, its biotechnological conversion into value-added compounds has been limited to a handful of examples. In this work, we engineered the natural formatotrophic bacterium C. necator as cell factory to enable biological conversion of formate into crotonate, a platform short-chain unsaturated carboxylic acid of biotechnological relevance. First, we developed a small-scale (150-mL working volume) cultivation setup for growing C. necator in minimal medium using formate as only carbon and energy source. By using a fed-batch strategy with automatic feeding of formic acid, we could increase final biomass concentrations 15-fold compared to batch cultivations in flasks. Then, we engineered a heterologous crotonate pathway in the bacterium via a modular approach, where each pathway section was assessed using multiple candidates. The best performing modules included a malonyl-CoA bypass for increasing the thermodynamic drive towards the intermediate acetoacetyl-CoA and subsequent conversion to crotonyl-CoA through partial reverse β-oxidation. This pathway architecture was then tested for formate-based biosynthesis in our fed-batch setup, resulting in a two-fold higher titer, three-fold higher productivity, and five-fold higher yield compared to the strain not harboring the bypass. Eventually, we reached a maximum product titer of 148.0 ± 6.8 mg/L. Altogether, this work consists in a proof-of-principle integrating bioprocess and metabolic engineering approaches for the biological upgrading of formate into a value-added platform chemical.

CHEMICAL COMPOSITION OF BIOLOGICAL PREPARATIONS OBTAINED BY BIOCONVERSION OF PEA AND CHICKPEA SERUM

In this work, we studied the chemical composition of preparations obtained by bioconversion of carotenoid yeast Rhodotorula mucilaginosa of pea and chickpea whey, a secondary product of flour processing into food protein concentrate. In the process of growth, yeast assimilate carbohydrate, nitrogenous components and provided the chemical composition of biological products, allowing them to be attributed to the highest group of fodder yeast. The chemical composition of dry biomass from whey: total protein (Nx6.25) – 58.90–61.29%, fat – 1.20–2.31%, ash elements – 3.53–4.53%, soluble and insoluble fibers – 9.33–10.35% and 22.52–26.04%, respectively. The biological effectiveness of lipids based on the study of the fatty acid composition of lipids: the ratio of saturated:monoenoic:polyenoic fatty acids is characterized by the predominance of unsaturated acids – 17 : 62 : 18 in the pea preparation and 18 : 33 : 45 in the chickpea preparation. The pea preparation contains 2.4 times more ω-6 of linoleic acid, the chickpea preparation contains 2.5 times more oleic acid. The biological effectiveness of lipids was also confirmed by chromatographic analysis of the composition of carotenoid components, which is represented by phytoin, torulene, β-carotene, torularodine and phytoin. There is no phytoin in the chickpea biological product, but β-carotene is present in a larger amount (2.8 times). The biological value of biological products with a yield of 0.50–0.54 g/100 cm3 is confirmed by the amount of essential amino acids and their rate (114–278% for pea and 120–242% for chickpea biological products). For both drugs, there is no toxicity in experiments with the ciliate Tetrahymena pyriformis, in the presence of which its active growth is observed. With a pea preparation, the growth factor is 29.1% higher than with distilled water, with a chickpea preparation it is 18.6% higher. In the body of animals, a biologically complete protein with essential amino acids, lipids and carotenoids in the composition of pea and chickpea preparations will actively participate in the metabolism not only as energy materials, but also as biologically active components in the synthesis of hormones, vitamins and other vital compounds.

Interaction of O- and P- nucleophiles with perfluorinated olefins: Novel synthetic route to fluorinated phosphorus-containing monomers

A novel synthetic method for the preparation of partially fluorinated unsaturated diethyl phosphonates and phosphonic acids is presented involving the deprotonation of the starting α-hydroxymethyl diethylphosphonate or diethylphosphite with a strong base, followed by in situ addition of an O- or P-nucleophile to the terminal double bond of the perfluorinated olefin. Subsequent elimination of the corresponding leaving groups and restoring of the double bond leads to the target bifunctional perfluorinated olefins. Reaction of the diethyl phosphonate group with trimethylsilyl bromide (TMS-Br) and subsequent hydrolysis/methanolysis gave the corresponding unsaturated phosphonic acids. In the case of using α-hydroxymethyl diethylphosphonate, the reaction may be accompanied by an addition of a second equivalent of an O-nucleophile to form bis-functional internal olefins. The reaction conditions, factors affecting the reactivity, stereo- and regioselectivity of the process, the choice of reagent as well as the course of competitive reactions are discussed, too.

Oxidation Kinetics of some Unsaturated Acids by Tributylammonium Chlorochromate: A mechanistic Study

The oxidation of maleic, fumaric, crotonic and cinnamic acids by tributylammonium chlorochromate (TBACC) in dimethylsulphoxide (DMSO) leads to the formation of corresponding epoxide. The reaction is of first order with respect to TBACC. A Michaelis-Menten type of kinetics are observed w.r.t. the acids. Due to non-aqueous nature of the solvents, toluene-p-sulphonic acid (TsOH) was used as the source of hydrogen ions. The reaction is catalysed by hydrogen ions. The hydrogen-ion dependence has the form: kobs = a + b [H+]. The oxidation of these acids was studied in nineteen different organic solvents. The solvent effect was analyzed by Kamlet’s and Swain’s multiparametric equations. Solvent effect indicated the importance of the cation-solvating power of the solvent. A mechanism involving a three-centre transition state has been postulated.

Microbial production of trans-aconitic acid

Trans-aconitic acid (TAA) is a promising bio-based chemical with the structure of unsaturated tricarboxylic acid, and also has the potential to be a non-toxic nematicide as a potent inhibitor of aconitase. However, TAA has not been commercialized because the traditional production processes of plant extraction and chemical synthesis cannot achieve large-scale production at a low cost. The availability of TAA is a serious obstacle to its widespread application. In this study, we developed an efficient microbial synthesis and fermentation production process for TAA. An engineered Aspergillus terreus strain producing cis-aconitic acid and TAA was constructed by blocking itaconic acid biosynthesis in the industrial itaconic acid-producing strain. Through heterologous expression of exogenous aconitate isomerase, we further designed a more efficient cell factory to specifically produce TAA. Subsequently, the fermentation process was developed and scaled up step-by-step, achieving a TAA titer of 60 g L−1 at the demonstration scale of a 20 m3 fermenter. Finally, the field evaluation of the produced TAA for control of the root-knot nematodes was performed in a field trial, effectively reducing the damage of the root-knot nematode. Our work provides a commercially viable solution for the green manufacturing of TAA, which will significantly facilitate biopesticide development and promote its widespread application as a bio-based chemical.

Novel biocidal polyampholytes with guanidinium and carboxy groups

AbstractPolyampholytes are a promising class of multifunctional polymers containing both cationic and anionic groups. By varying the total charge of the copolymers, it is possible to significantly change the properties of the target macromolecule, such as molecular weight, solubility, reactivity, etc. In an attempt to create new polyampholytes, here the radical copolymerization of 2,2‐diallyl‐1,1,3,3‐tetraethylguanidinium chloride (AGC) with acrylic (AA), methacrylic (MAA), vinylacetic (VAA), and crotonic (CA) acids in bulk and in organic solvents has been studied and described. The relative reactivity of the unsaturated acids in the radical copolymerization with AGC in bulk appears to be MAA > AA > CA > VAA. It is shown that both AGC double bonds participate in copolymerization with unsaturated acids, forming a cyclolinear polymer chain including cis/trans‐stereoisomeric pyrrolidinium subunits. The kinetics of this polymerization has been studied. The possibility and prospects of chemical modifications of copolymers by drugs bearing an amino group are considered. Moreover, the copolymers under study, including the guanidinium moiety, are effective against Gram‐positive and Gram‐negative bacteria.

Dimer-assisted mechanism of (un)saturated fatty acid decarboxylation for alkene production

The enzymatic decarboxylation of fatty acids (FAs) represents an advance toward the development of biological routes to produce drop-in hydrocarbons. The current mechanism for the P450-catalyzed decarboxylation has been largely established from the bacterial cytochrome P450 OleTJE. Herein, we describe OleTPRN, a poly-unsaturated alkene-producing decarboxylase that outrivals the functional properties of the model enzyme and exploits a distinct molecular mechanism for substrate binding and chemoselectivity. In addition to the high conversion rates into alkenes from a broad range of saturated FAs without dependence on high salt concentrations, OleTPRN can also efficiently produce alkenes from unsaturated (oleic and linoleic) acids, the most abundant FAs found in nature. OleTPRN performs carbon-carbon cleavage by a catalytic itinerary that involves hydrogen-atom transfer by the heme-ferryl intermediate Compound I and features a hydrophobic cradle at the distal region of the substrate-binding pocket, not found in OleTJE, which is proposed to play a role in the productive binding of long-chain FAs and favors the rapid release of products from the metabolism of short-chain FAs. Moreover, it is shown that the dimeric configuration of OleTPRN is involved in the stabilization of the A-A' helical motif, a second-coordination sphere of the substrate, which contributes to the proper accommodation of the aliphatic tail in the distal and medial active-site pocket. These findings provide an alternative molecular mechanism for alkene production by P450 peroxygenases, creating new opportunities for biological production of renewable hydrocarbons.

Direct synthesis of a new hybrid molecules based on isomerically pure 5<i>Z</i>,9<i>Z</i>-dienoic acids and monocarbonyl derivatives of curcuminoids

Synthesis of previously undescribed hybrid compounds based on monocarbonyl derivatives of curcumin and 5 Z ,9 Z -dienoic acids with yields of 61-67% was carried out for the first time. Unsaturated acids are synthesized using at the key stage of stereoselective reaction of intermolecular cross-cyclomagnesiation of aliphatic and O-containing 1,2-dienes catalyzed by Cp2TiCl2.

Visible‐Light Photoredox‐Catalyzed Acyl Lactonization of Alkenes with Acyl Chlorides

AbstractA photocatalytic acyl lactonization of unsaturated carboxylic acids using simple and inexpensive acyl chlorides has been developed for a modular synthesis of acyl lactones. Significantly, the simple protocol could allow an efficient construction of biologically important phthalide framework. The transformation could be extended to a wide variety of unsaturated carboxylic acids, including substituted 2‐vinyl benzoic acids and different types of alkenoic acids. Moreover, a series of aroyl, heteroaroyl chlorides could serve as coupling partners. Notably, functional groups including MeO, F, Cl and Br could survive. It is believed that acyl radicals generated from acyl chlorides under photoredox catalysis reacted with alkenes via atom‐transfer radical addition (ATRA) and triggered subsequent lactonization in the process. Preliminary mechanistic investigations revealed that the transformation probably proceeded through a free radical pathway.

Polycondensation of Acid anhydrides with Asparaginyl Imide Diamine and Curing with Styrene as Smart Polymers for Sustained Release Drug Delivery System

Polymers can provide new and effective ways of administering drugs and enhance therapeutic efficacy. Polymers also present a means for controlled delivery of several drugs in the form of polymeric drug carriers or polymeric prodrugs. Our study involved synthesize of new condensed polymers from reacting of unsaturated acid anhydride such as maleic or methylnadic anhydrides, with prepared N-asparaginyl imide diamine, which prepared from reacting of asparaginyl chloride with ammonia. The new condensed polymers were curing with styrene and the cross-linked polymers were obtained with high conversion percent. The physical properties were measured and all the prepared monomers and polymers were characterized by FT-IR and UV spectroscopy. The intrinsic viscosity was calculated and swelling index was measured for the prepared cross-linked polymers. The inserted asparagine as amino acid could enhance the biodegradability properties, and these prepared bioactive polymers can be used as biomaterial in different applications, which could be acted as smart polymers due to pH sensitivity.

Growth Inhibitory Effects of Unsaturated Linoleinic Acid with Conjugated Double Bonds for Cancer Prevention

Growth Inhibitory Effects of Unsaturated Linoleinic Acid with Conjugated Double Bonds for Cancer Prevention

Growth Inhibitory Effects of Unsaturated Linoleinic Acid with Conjugated Double Bonds for Cancer Prevention

Growth Inhibitory Effects of Unsaturated Linoleinic Acid with Conjugated Double Bonds for Cancer Prevention

The role of fatty acids in disturbance of energy processes in the early placenta with cytomegalovirus infection

Introduction. Cytomegalovirus (CMV) infection directly and indirectly can cause placental dysfunction. One of the reasons for its development may be a deficiency of energy supply due to changes in the level of fatty acids (FA) – the main sources of energy in the cell.Aim. Analysis of the fatty acids concentration and causes of its changes in the placenta during exacerbation of CMV infection in the first trimester of pregnancy.Materials and methods. Biosamples (venous blood, epithelium from the inner surface of the cheek, mucous membrane of the cervical canal, villous chorion) of 32 CMV-seropositive women with an exacerbation of CMV infection in the first trimester of pregnancy (main group) and 30 CMV-seronegative women (control group) were studied. Exacerbation of CMV infection was diagnosed by ELISA to detect IgM and IgG with avidity of 65% or more, PCR to detect CMV DNA. The profile and relative concentration of individual FA in villous chorion lipid extracts were studied by gas-liquid chromatography. The activity of pyruvate dehydrogenase, succinate dehydrogenase, NADP-dependent malate dehydrogenase, and glucose-6-phosphate dehydrogenase was determined by a histochemical method on sections of freshly frozen villous chorion tissues.Results. In the main group placentas, the concentration of medium-chain saturated fatty acids was statistically significantly lower: capric by 50%, lauric by 51%, unsaturated myristoleic by 44%; long-chain unsaturated acids: palmitoleic, oleic, linoleic and α-linolenic fatty acids by 52%, 55%, 57% and 64%, respectively; of polyunsaturated fatty acids with a very long chain: eicosapentaenoic and docosahexaenoic by 44% and 41%, respectively. The activity of enzymes: succinate dehydrogenase, pyruvate dehydrogenase, NADP-dependent malate dehydrogenase and glucose-6-phosphate dehydrogenase decreased.Conclusion. Thus, we found a decrease in energy supply in the placenta during exacerbation of chronic CMV infection in the first trimester of pregnancy. Disorders of placental energy metabolism can cause placental insufficiency, which has adverse consequences for fetal development.

Synthesis of Selenoflavones via Ruthenium-Catalyzed Selenylation of Unsaturated Acids

An efficient method for pharmaceutically useful selenoflavones via a ruthenium-catalyzed selenylation reaction is demonstrated. The ruthenium-catalyzed selenylation was applied to synthesize diverse alkenyl selenides from simple unsaturated acids/amides and diaryl diselenides. A wide range of differently substituted diaryl diselenides can be applied in this protocol with a good functional group with excellent stereo- and regioselectivity.

Investigation of the fatty acid composition of vegetable oils

Emulsion fat products are a promising direction for the enrichment of unsaturated groups with fatty acids. This is possible by introducing rarely used types of vegetable oils into the formulations of these products. Due to the fact that the fatty acid composition of vegetable oils differs depending on the properties of the raw materials from which it is produced, there is a need for its analysis for a more accurate formulation of the emulsion product. As a result of the conducted studies, 17.3% saturated fatty acids and 83% unsaturated, respectively, were found in pumpkin oil. Pumpkin oil is rich in monounsaturated fatty acids, such as oleic acid (47%). Chromatographic study of the fatty acid composition showed that ginger oil contains 9.7% saturated fatty acids and about 90.3% unsaturated acids. Linolenic acid turned out to be the most in the oil (32.6%). It was found that the sample of black cumin oil contains 21.9% saturated and 78.1% unsaturated fatty acids. Most of all in linoleic acid oil (about 56.9%). The studied oils are rich in unsaturated fatty acids and can be used as additives in mayonnaise sauces to saturate certain groups with unsaturated fatty acids, each of the studied oils will saturate a certain group. Pumpkin oil is a source of monounsaturated fatty acids (oleic fatty acid), ginger oil is a source of omega–3 fatty acids (linolenic fatty acid), black cumin oil is a source of omega–6 fatty acids (linoleic fatty acid).

Changes of lipid composition from culture fluid during the production of antibiotic salinomycin

A major step in the biotechnological process of production of antibiotic salinomycin is fermentation, which has the greatest impact on the quality of the final product. Vegetable oils (rapeseed or soybean) are used as nutrient medium during fermentation, with some of the lipids embedded in the final product. Data on their effect on product quality is missing, which is why a study of the changes in the composition of lipids in cultural fluid during the fermentation process was conducted. The composition of the residual lipids isolated from three samples of the culture fluid during fermentation (213, 405 and 490 hours), was investigated before drying the final product. The lipid content of the samples was 6.3%, 3.5% and 6.2%. The main trend is an increase in the amount of saturated fatty acids at the expense of a decrease in unsaturated acids. The amount of tocopherols during the fermentation process increased as well as γ-tocopherol, while the amount of α-tocopherol decreased. The content of carotenoids decreased twice during fermentation. Phosphatidylcholine and phosphatidylethanolamine were identified as major polar lipid components. The main phospholipid classes contain mainly palmitic, stearic and oleic acids. Significant changes in general lipid composition were observed during the biosynthesis process.

Concise Enantioselective Total Synthesis of Isopavine Alkaloids.

Herein, we report a concise asymmetric total synthesis of isopavine alkaloids, which feature a special azabicyclo[3.2.2]nonane tetracyclic skeleton. The key steps include iridium-catalyzed asymmetric hydrogenation of unsaturated carboxylic acids, Curtius rearrangement, and Eschweiler-Clarke methylation, which enable an enantioselective approach to isopavine alkaloids in 6-7 linear steps. Furthermore, for the first time, isopavine alkaloids, especially (-)-reframidine (3), are found to display effective antiproliferative effects on various cancer cell lines.

Stereospecific Single-Pot Route to Chiral Imidazolidines from Aziridines Using a 2D Cu Metal–Organic Framework

The role of coordinatively unsaturated sites (CUS) in metal-organic framework (MOF)-catalyzed organic transformation is vital; however, the design and generation of such sites are challenging. We, therefore, report the synthesis of a novel two-dimensional (2D) MOF, [Cu(BTC)(Mim)]n (Cu-SKU-3), with pre-existing unsaturated Lewis acid sites. The presence of these active CUS facilitates a ready-to-use attribute in Cu-SKU-3, thereby subsiding the lengthy activation processes associated with MOF-based catalysis. The material has been completely characterized using single crystal X-ray diffraction (SCXRD), powder XRD (PXRD), thermogravimetric analysis (TGA), carbon, hydrogen, and nitrogen (CHN), Fourier-transform infrared (FTIR), and Brunauer-Emmett-Teller (BET) surface area analyses. We directly utilize Cu-SKU-3 for the synthesis of biologically valued chiral imidazolidine motifs in a one-pot fashion starting from aziridines. The chiral imidazolidines are synthesized in good yield (up to 89%) and with high optical purity (ee > 98-99%). Mechanistically, the transformation proceeds in a tandem fashion through stereospecific ring-opening of aziridines followed by the intramolecular cyclization (via sp3 C-H functionalization) reaction forming chiral imidazolidines. The material has an excellent heterogeneous attribute and can be reused several times for one-pot catalytic cycles.

Degradation of 8:2 fluorotelomer carboxylic acid (8:2 FTCA) by plants and their co-existing microorganisms

8:2 fluorotelomer carboxylic acid (8:2 FTCA), an important precursor of perfluorocarboxylic acids (PFCAs), is widely detected in environment and biotas. Hydroponic exposures were conducted to investigate the accumulation and metabolism of 8:2 FTCA in wheat (Triticum aestivum L.) and pumpkin (Cucurbita maxima L.). Endophytic and rhizospheric microorganisms co-existing with the plants were isolated to investigate their contributions to degrade 8:2 FTCA. Wheat and pumpkin roots could take up 8:2 FTCA efficiently with the root concentration factor (RCF) as 5.78 and 8.93, respectively. 8:2 FTCA could be biotransformed to 8:2 fluorotelomer unsaturated carboxylic acid (8:2 FTUCA), 7:3 fluorotelomer carboxylic acid (7:3 FTCA), and seven PFCAs with 2–8 carbon chain length in plant roots and shoots. Cytochromes P450 (CYP450) and glutathione-S-transferase (GST) activities in plants were significantly increased, while flavin-dependent monooxygenases (FMOs) activities were not changed, suggesting that CYP 450 and GST were involved in the transformation of 8:2 FTCA in plant tissues. Twelve 8:2 FTCA-degrading endophytic (8 strains) and rhizospheric (4 strains) bacterial strains were isolated from root interior, shoot interior and rhizosphere of plants, respectively. These bacteria were identified as Klebsiella sp. based on the morphology and 16S rDNA sequence, and they could biodegrade 8:2 FTCA to intermediates and stable PFCAs.