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Three new trichostatin analogues, ulleunganilines A-C (1-3), and seven known trichostatins (4-10) were isolated from cultures of Streptomyces sp. 13F051. NMR, UV, and MS data indicated that the planar structures of 1-3 consisted of modified side chains in the trichostatic acid moiety. The absolute configuration of the 2,4-dimethyl-branched carbon chains in 1 and 2 was determined by the PGME method, while the amino acid group in 3 was identified by advanced Marfey's method. Based on the structure of the modified side chains, the origin of 1-3 is proposed. Further experiments indicated that 1 and 3 displayed moderate histone deacetylase inhibitory activity, suggesting that not only the hydroxamate group but also the N,N-dimethyl group were essential for the inhibitory activity.

Ketonization reactions provide a feasible approach to remove oxygen and increase carbon chain length for conversion of biomass derived carboxylic acids. However, the reaction suffers from fast catalyst deactivation and low ketone selectivity. In this work, Lewis acidic heteroatom Ti-, Zr-, Ce-, and Sn-Beta zeolites were prepared using a two-step post-synthesis method and applied in vapor phase ketonization of propionic acid at 350 °C. Among these zeolites, Zr-Beta shows both the highest activity and selectivity. Characterizations indicate that Zr prefers the vacant tetrahedral site when the Zr content is 96% at a space time of 2 h. The amount of coke deposition on Zr-Beta is about 1/3 of that on H-Beta, and the structure of Zr-Beta is preserved after 60 h of reaction. The results of this work indicate that Zr-Beta zeolite is a promising catalyst for ketonization with good stability and high selectivity toward ketone.

The adsorption dynamic and thermodynamic characteristics of Na-Montmorillonite (Na-MT) with two different layer charge density for four types of alkyl ammonium with diverse carbon chain length were systematically studied. The result of adsorption dynamics shows that the adsorption process of Na-MT for alkyl ammonium follows the quasi-second-order dynamics equation; with the increase of layer charge density or carbon chain length of alkyl ammonium, the adsorption reaction rate of Na-MT for alkyl ammonium gradually increases; the adsorption reaction rate of Na-MT for alkyl ammonium at a low amount of added modifier is significantly higher than that at a high amount. The result of adsorption thermodynamics indicates that the adsorption process of Na-MT for alkyl ammonium is an exothermic reaction, and the adsorption efficiency of Na-MT for alkyl ammonium decreases with the decrease of layer charge density or carbon chain length of alkyl ammonium. The change in the entropy of adsorption reaction ΔS showes a decreasing trend after the first increase when the amount of added alkyl ammonium increases; at the same amount of added alkyl ammonium, the increase of temperature contributes to the spontaneous adsorption of Na-MT for alkyl ammonium, and the strength of the spontaneous adsorption process is negatively correlated with the carbon chain length and the amount of added alkyl ammonium. The research result of this study provides a theoretical basis for the application of the adsorption of montmorillonite for alkylammonium in industry.

Super-carbon-chain compounds (SCCCs) are marine organic molecules featuring long polyol carbon chains with numerous stereocenters. Polyol–polyene compounds (PPCs) and ladder-frame polyethers (LFPs) are two major families. It is highly challenging to establish the absolute configurations of SCCCs. In this century, few new SCCC families have been reported. Benthol A, an aberrant SCCC, was obtained from a South China Sea benthic dinoflagellate that should belong to a new taxon. Its planar structure and absolute configuration, containing thirty-five carbon stereocenters, were unambiguously established by a combination of extensive NMR spectroscopic investigations, periodate degradation of the 1,2-diol groups, ozonolysis of the carbon–carbon double bonds, J-based configurational analysis, NOE interactions, modified Mosher's MTPA ester method, and DFT-NMR 13C chemical-shift calculations aided by DP4+ statistical analysis. Benthol A displayed potent antimalarial activity against Plasmodium falciparum 3D7 parasites. This new molecule combines extraordinary structural features, particularly eight scattered ether rings on a C72 backbone chain, which places it within a new SCCC family between PPCs and LFPs, herein termed polyol–polyether compounds. This suggestion was strongly supported by principal component analysis. The discovery of benthol A does not only provide new insights into the untapped biosynthetic potential of marine dinoflagellates, but also opens up a new window for skeletal diversity of SCCCs., The discovery of benthol A, a marine natural product featuring thirty-five carbon stereocenters and eight scattered ether rings within a C72 backbone chain, inaugurates a new family of super-carbon-chain compounds.

In in vitro cell assays, nominal concentrations of a test chemical are most frequently used in the description of its dose-response curves. Although the biologically effective concentration (BEC) is considered as the most relevant dose metric, in practice, it is very difficult to measure. In this work, we attempted to determine the BEC of long-chain perfluoroalkyl carboxylic acids (PFCAs) in peroxisome proliferator-activated receptor γ (PPARγ) activity assays. In both adipogenesis and transcriptional activity assays with human and mouse cells, PPARγ activity of 7 PFCAs first increased and then decreased with their carbon chain length. The binding affinity of these PFCAs with the ligand-binding domain of PPARγ was measured by fluorescence competitive binding assay and showed very poor correlation with their receptor activity (r2 = 0.002-0.047). Internal concentrations of the PFCAs in the cells were measured by LC-MS/MS. Although their correlation with the receptor activity increased significantly, it is still low (r2 = 0.41-0.82). Using the binding affinity constant, internal concentration, and PPARγ concentration measured by immunoassays, concentrations of receptor-bound PFCAs in cells were calculated, which exhibited excellent correlation with PPARγ activity in both adipogenesis and transcriptional activity assays (r2 = 0.91-0.93). These results demonstrate that the concentration of receptor-bound PFCA is the BEC that dictates its activity on human and mouse PPARγ in cell assays. In the absence of any direct detection method, our approach can be used to calculate the target-site concentration of other ligands.

Allenes (carbodicarbenes) and [3]cumulenes are linear carbon chains that can be bent when the terminal group has a strong carbene nature. This bending can be quite pronounced in allenes but not in [3]cumulenes. In this study, how N-heterocyclic or cyclic (alkyl)(amino) carbene (NHC and CAAC, respectively) terminal groups can modify the linear structure of [n]cumulenes has been analyzed. A low π acidity of the terminal carbene affects the linearity of [2n]cumulenes. Indeed, it has been found that the NHC [4]cumulene is extremely bent, contrary to classical [4]cumulenes. The predicted NHC [4]cumulene or tricarbodicarbene has two lone pairs and the π electrons are delocalized over the whole molecule. More significantly, DFT calculations have shown that this bent [4]cumulene is very stable, considerably more so than the corresponding [3]cumulene, which has been elusive to synthesize. Remarkably, calculations have shown that all the NHC [2n]cumulenes are more than 25 kcal mol-1 more stable than the [2n-1]cumulenes.

Pyclen-dipicolinate chelates proved to be very efficient chelators for the radiolabeling with β–-emitters such as 90Y. In this study, a pyclen-dipicolinate ligand functionalized with additional C12 alkyl chains was synthesized. The radiolabeling with 90Y proved that the addition of saturated carbon chains does not affect the efficiency of the radiolabeling, whereas a notable increase in lipophilicity of the resulting 90Y radiocomplex was observed. As a result, the compound could be extracted in Lipiodol® and encapsulated in biodegrable pegylated poly(malic acid) nanoparticles demonstrating the potential of lipophilic pyclen-dipicolinate derivatives as platforms for the design of radiopharmaceuticals for the treatment of liver or brain cancers by internal radiotherapy.

The biochemical basis of lower metmyoglobin reducing activity (MRA) in high-oxygen modified atmospheric packaged (HiOx-MAP) beef than those in vacuum and polyvinyl chloride (PVC) packaging is not clear. To explore this, the effects of lipid oxidation products with varying carbon chain length on lactate dehydrogenase (LDH) and NADH-dependent metmyoglobin reductase activity were evaluated. Surface color, MRA, and lipid oxidation of beef longissimus lumborum steaks (n = 10) were measured during 6-day display. Further, two enzymes, LDH and NADH-dependent metmyoglobin reductase (n = 5), critical for MRA were incubated with or without (control) lipid oxidation products of varying carbon chain length: malondialdehyde (3-carbon), hexenal (6-carbon), and 4-hydroxynonenal (9-carbon). Steaks in HiOx-MAP had greater (P MDA = hexenal) and NADH-dependent metmyoglobin reductase (HNE = MDA > hexenal) activity could be responsible for lower MRA in HiOx-MAP.

Background:Fatty acid is a type of carboxylic acid with carbon chain that can be short (4 carbons, such as butyric acid) or long (14 carbons and more, like DHA). Generally, fatty acids are divided into two groups of unsaturated fatty acids and saturated fatty acids. They have important and valuable medicinal properties especially against microbial pathogens.Objective:Studies have shown that the epidemic of the twentieth century's heart disease is due to the abuse of trans fatty acids. The consumption of various fatty acids has various therapeutic effects on various diseases.Method:Relevant articles were searched from Google Scholar, Pub Med, Scopus, Science direct, and Cochrane library.Results:Getting omega-3 fatty acids through diet and supplements affects both acute and chronic inflammation. Consumption of omega-3 fatty acids can slow down the growth of cancer, increase the effect of chemotherapy and reduce the side effects of chemotherapy or cancer. This can be done by reducing angiogenesis in the tumor, creating the differentiation of cancer cells, reducing the risk of heart attack from cancer, etc.Conclusion:In general, fatty acids are valuable and affordable, and available with numerous medicinal properties, including anti-fungal and anti-bacterial properties that can be extracted from and used by many sources, especially many medicinal plants. Since antimicrobial chemicals generally have many side effects and have resistance to many microbial species, various studies and experiments to identify and extract fatty acids and their application to the title of the pharmaceutical formulation are essential.

A detailed study on the foaming properties of sodium N-acyl glycinate(N-CnG, n = 12, 14,16,18)and sodium N-acyl phenylalaninate(N-CnP, n = 12, 14,16,18)with different carbon chain lengths were performed. The effects of hydrophilic group, hydrophobic group, surfactant concentration and temperature were evaluated on the foamability, foam morphology and foam stability by foam scanning method. The results showed that the foamability and foam stability of N-C12G were better than that of N-C12P. In addition to N-C14P, with the increase of alkyl carbon chain, the foamability of sodium N-acyl amino acid decreased, but the foaming stability gradually increased. With the increase of concentration, the foamability of the two kinds of surfactants increased first and then decreased. The increase of temperature was beneficial to the foamability of N-CnP, but the foam stability decreased. At higher temperatures, the longer alkyl chain was, the stronger the foamability and foam stability of N-CnP were. With the increasing of alkyl carbon, the maximum liquid carrying capacity and liquid drainage rate of N-CnG decreased. At the same concentration and alkyl carbon number, N-CnP had higher maximum liquid carrying capacity than N-CnG. The number of bubbles initially increased and then decreased, and the morphology of bubbles gradually changed from sphere to polyhedron.

The use of oxygenated components is an effective way to suppress soot formation and reduce particulate matter emission in diesel engines. Based on the group additivity method, we proposed a new statistical model with kernel ridge regression (KRR) to predict the sooting tendencies of oxygenated components and interpret the experimental results of fuel sooting tendency. Through a training process, the relationship between fuel molecular structure and sooting tendency was built. In the testing process, the predicted values of the yield sooting index were in good agreement with the measured values, indicating that the KRR model had good predictive performance. The KRR method can be used to compare the sooting tendencies of various components that are important in traditional or new fuels. For example, based on the predicted results of typical five-carbon oxygenated compounds, the inhibiting effects of oxygen functional groups on sooting tendency are in the following order: esters > ketones ≈ aldehydes > ethers > alcohols. In addition, the proposed method provides statistical evidence for the effects of structural features on sooting tendencies. The predictive results for typical ethers indicate that although sooting tendencies increase as carbon chains become more branched, they are not very sensitive to the specific arrangement of the branches compared with the effect of carbon chain length. Moreover, the KRR method is useful for studying non-nearest-neighbor interactions, including functional group interactions. By predicting the sooting tendencies of typical esters, the coupling of ester moiety and C C double bonds shows an overall enhancing effect on sooting tendency, which indicates that C C double bonds play a dominant role in soot formation. This method provides an alternative way to obtain the sooting tendencies of fuel compounds and verifies the selection of low-sooting fuels from a wide range of feedstocks.

The study provided a microsphere profile control agent, which can smoothly go deep into the stratum by using the hydrophobic shell structure as the “protective film”. While the solution time in simulated brine was prolonged, water molecules went deep into the inside of the microsphere particles through the pore structure, and combined with hydrophilic groups. Because of the combination, the microsphere polymer started to swell, and opened the shell into long chain for days, and then at the end, its hydrophilic-hydrophobic block groups were all exposed in the solution, which resulted in self-thickening property. The dissolution time after entering into the stratum, i.e. the shell “rupture” time can be controlled by adjusting the carbon chains length of hydrophobic groups in the synthetic process. The agent can not only prolong the depth of plugging and provide a stable plugging rate, but also enlarge the water swept volume after dissolution. This method can stabilize the oil production and control the water cut. The function of delayed thickening ability makes the stratum sealed but kept at a certain permeability.

Isomerizing olefin metathesis is currently undergoing a transformation from laboratory curiosity to powerful synthetic concept at the heart of orthogonal tandem catalysis. In this process, an isomerization catalyst continuously moves double bonds along carbon chains, while a metathesis catalyst scrambles the residues at the C-C double bonds. This cooperative action of two catalysts can be used to access single, defined products from a complex mixture of compounds. Alternatively, it enables the transformation of uniform starting materials into complex product blends with defined, tunable properties. This concept article highlights recent developments and potential applications of this fascinating reaction concept.

A novel synthetic route towards two series of enantiomerically pure cyclic analogues of 2,3-cis- and 2,3-trans-γ-aminobutyric acid (GABA) was developed. The route is based on the elongation and stereodivergent manipulation of a readily accessible enantiomerically pure γ-substituted α-aminolactone. The five-step route towards the 2,3-cis-substituted GABA analogues was achieved via straightforward carbon chain extension of the lactone using a non-classical Wittig reaction followed by chemoselective reduction and a protecting group switch. The five-step route towards the 2,3-trans-substituted GABA analogues employed elongation of the same aminolactone using a Horner-Wadsworth-Emmons reaction and highly stereoselective intramolecular oxa-Michael addition as the key synthetic manipulations. Altogether this chemistry has allowed the stereodivergent preparation of a novel class of GABA analogues in two diastereomeric series.

The fat consumption in the human diet is based on the intake of two types of fatty acids, namely, saturated (SFA) and unsaturated (UFA) fatty acids. Unsaturated fatty acids, which are grouped into monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA), have been scientifically proven to positively contribute to human health when consumed in a regular diet. However, one of the isomers occurring in the carbon chain, which are called trans fatty acids (commonly “trans fats”), gained specific interest due to their adverse health effects. Trans fatty acids either occur naturally or are the components derived during oil processing such as partial hydrogenation, refining, and deep-fat frying. Since the physicochemical attributes of the fatty acids change when shifting from cis to trans isomerization, trans fats have been widely studied to reveal their impacts on humans. Even though naturally occurring trans fats are considered less harmful than artificial trans fats, the risk of being negatively affected by trans fatty acids in regard to issues such as cardiovascular diseases, diabetes, obesity, several cancers, asthma, allergic reactions, and increased LDL cholesterol is a worldwide medical concern in general. In the last two or three decades, there was a great interest in processed foods such as shortenings, potato chips, margarine, fast food, snacks, and fried foods due to their desirabilities by consumers, but their trans-fat contents made these products to be questioned soon. Today, many countries and organizations have been conducting investigations to limit the maximum amount of trans fats in such processed foods with a high content of fat. This chapter aims to provide further information about the nature, occurrence, and global regulations of trans fatty acids.

l-Valine, l-isoleucine, and l-leucine are three key proteinogenic amino acids, and they are also the essential amino acids required for mammalian growth, possessing important and to some extent, special physiological and biological functions. Because of the branched structures in their carbon chains, they are also named as branched-chain amino acids (BCAAs). This review will highlight the advance in studies of the enzymes involved in the biosynthetic pathway of BCAAs, concentrating on their chemical mechanisms and applications in screening herbicides and antibacterial agents. The uses of some of these enzymes in lab scale organic synthesis are also discussed.

A super-carbon-chain compound, named gibbosol C, featuring a polyoxygenated C70-linear-carbon-chain backbone encompassing two acyclic polyol chains, was obtained from the South China Sea dinoflagellate Amphidinium gibbosum. Its planar structure was elucidated by extensive NMR investigations, whereas its absolute configurations, featuring the presence of 36 carbon stereocenters and 30 hydroxy groups, were successfully established by comparison of NMR data of the ozonolyzed products with those of gibbosol A, combined with J-based configuration analysis, Kishi&rsquo, s universal NMR database, and the modified Mosher&rsquo, s MTPA ester method. Multi-segment modification was revealed as the smart biosynthetic strategy for the dinoflagellate to create remarkable super-carbon-chain compounds with structural diversity.

Alkanes are a fundamental part in empirical force fields (FF) not only due to their technological relevance, but also due to the prevalence of alkane moieties in organic molecules, e.g., compounds containing a saturated carbon chain. Therefore, a good description of alkane interactions is crucial for determining the quality of a FF. In this study, the performance of 12 empirical force fields (FF) was evaluated in the context of reproducing liquid properties of alkanes. More specifically, n-octane was chosen as a reference compound since it is a liquid in a broad temperature range and it has numerous experimental data for thermodynamic, transport, and structural properties, as well as for their temperature dependencies. A normalized root-mean-square deviation (NRMSD) analysis was used to rank the force fields in their ability to reproduce the experimental data. Five out of the six best force fields considered were united-atom models. The GROMOS force field showed the smallest deviation in terms of NRMSD, followed by TRAPPE-EH, NERD, CHARMM-UA, TRAPPE-UA, and OPLS-UA. This overall better performance of the united-atom force fields indicates that complexity does not always bring quality.

This review is centered on the linear conjugated polyenes, which encompasses chromatic biomolecules, such as carotenoids, polyunsaturated aldehydes and polyolefinic fatty acids. The linear extension of the conjugated double bonds in these molecules is the main feature that determines the spectroscopic properties as light-absorbing. These classes of compounds are responsible for the yellow, orange, red and purple colors which are observed in their parent flora and fauna in nature. Raman spectroscopy has been used as analytical tool for the characterization of these molecules, mainly due to the strong light scattering produced by the delocalized pi electrons in the carbon chain. In addition, conjugated polyenes are one of the main target molecular species for astrobiology, and we also present a brief discussion of the use of Raman spectroscopy as one of the main analytical tools for the detection of polyenes extra-terrestrially.

In this present study, simple linear equations were developed for predicting the thermo-physical properties of beef tallow biodiesel by considering their molecular weight and number of double bonds as two independent variables. Interestingly, molecular weight signifies as a function of carbon chain length and number of carbon molecules in it whereas numbers of double bond signifies the degree of unsaturation.

Polyketone compounds play an important role in organic chemistry as a prominent source of reactivity and functionality. Their chemical properties vary widely depending on the ketone sequence in carbon chains. Although vicinal and β-polyketones have been used for more than 150 years, the recent development of new ketone sequences composed of alternating 1,3- and 1,4-diketones has demonstrated the further potential of polyketones as structurally flexible molecular ropes capable of derivatization to π-conjugated chromophores and molecular assemblies. In this Feature Article, we review the synthetic strategies and reactivities of polyketones with respect to their ketone sequence. Furthermore, recent research on polyketones with hybrid ketone sequences is also discussed, focussing on their structural diversity in chemical transformations including intramolecular cyclization and stereoselective oxidation.

Intermolecular hydroalkylation of unactivated terminal alkenes with 1,3-diketones under neutral conditions has been achieved using a cationic iridium catalyst. An active C-H bond of 2,4-pentadione (2a) added to 1-octene (1a) under refluxing DCE to give a Markovnikov product in 88% yield. A broad scope of alkenes and 1,3-diketones was observed. The products were easily converted to heterocycles. This reaction provides a new method for extending a carbon chain from an unactivated aliphatic terminal alkene.

The sequential reaction of [Ru(C[triple bond, length as m-dash]CC[triple bond, length as m-dash]CH)Cl(CO)2(PPh3)2] with [Ru(CO)2(PPh3)3], and N-chlorosuccinimide affords the binuclear tetracarbido complex [Ru2(μ-C[triple bond, length as m-dash]CC[triple bond, length as m-dash]C)Cl2(CO)4(PPh3)4]. This may be compared with the first example of a butenyndiyl bridged bimetallic complex [Ru2(μ-CH[double bond, length as m-dash]CHC[triple bond, length as m-dash]C)Cl2(CO)4(PPh3)4] which is obtained from the reaction of [Ru(C[triple bond, length as m-dash]CC[triple bond, length as m-dash]CH)Cl(CO)2(PPh3)2] with [RuHCl(CO)(PPh3)3] followed by carbonylation. Characterisational data are discussed with reference to constituent model complexes [Ru(C[triple bond, length as m-dash]CH)Cl(CO)2(PPh3)2] and [Ru(CH[double bond, length as m-dash]CH2)Cl(CO)2(PPh3)2] in addition to DFT analysis of the bonding in the complexes [Ru2(μ-L)Cl2(CO)4(PMe3)4] (L = C[triple bond, length as m-dash]C-C[triple bond, length as m-dash]C, CH[double bond, length as m-dash]CHC[triple bond, length as m-dash]C, CH[double bond, length as m-dash]CH-CH[double bond, length as m-dash]CH). A range of other tetracarbido complexes which may be prepared from [RuCl(C[triple bond, length as m-dash]CC[triple bond, length as m-dash]CH)(CO)2(PPh3)2] is also described and includes [RuAu(μ-C4)Cl(CO)3(PPh3)3], [RuIr(μ-C4)Cl(CO)3(PPh3)4], [RuIr(μ-C4)H(NCMe)(CO)3(PPh3)4]BF4, [RuIr(μ-C4)Cl(η2-O2)(CO)3(PPh3)4], [Ru2Hg(μ-C4)2Cl2(CO)4(PPh3)4], [Ru2Pt(μ-C4)2Cl2(CO)4(PPh3)6] and [Ru2(μ-C4)HCl(CO)4(PPh3)4].

The cocrystal formation potential of betulin with aliphatic dicarboxylic acids was investigated. Carboxylic acids of varying carbon chain length, namely: adipic, succinic and suberic acids, were selected to explore the effect of the coformer structure on cocrystal formation when liquid-assisted grinding was used. Cocrystal formation was characterized by powder XRD and IR studies. Betulin cocrystals with adipic acid were successfully synthesized and HPLC analysis showed that solubility of the betulin cocrystal was significantly improved compared to the initial betulin and its mechanocomposite with polymer

We synthesized a series of small symmetrical unsaturated disulfides by a multi-step reaction starting from organic alcohols, and we performed a preliminary test to evaluate the effect of these compounds on the viability of A549 lung cancer cells. The garlic-derived natural compound diallyl disulfide, known for its anticancer activity, was used as the lead compound in this study. We synthesized five DADS analogues having different carbon chain lengths and different positions of the double bonds. Two analogues exhibited a promising antitumor activity in vitro, and the allylic double bond did not seem to be the main driving force.

We describe a nickel-catalyzed highly regio- and stereoselective migratory fluoro-alkenylation of unactivated alkyl bromides. A unique catalytic cycle merging alkyl nickel chain-walking and defluorinative coupling enables the introduction of a broad array of fluoroalkenyl moieties into carbon chains. Control experiments with other halogenated alkenes demonstrated the essential role of fluorine atoms in this reaction. Notably, the reaction proceeds under mild conditions and allows for the synthesis of a variety of valuable monofluoroalkenes.

New D–π–A type phenothiazine-modified 2-hydroxychalcone analogues PTNn (n = 2, 4, 8, 12, and 16) have been synthesized, and they exhibited reversible mechanofluorochromism. Notably, the emission of PTNn in different solid-states was in the range of 600–800 nm, and red-emitting mechanofluorochromic (MFC) materials were seldom reported. The as-synthesized crystals of PTN16 emitted red light centered at 667 nm, and were changed into deep red emitting ground powders after grinding. The fluorescence emission could be recovered to the original state when the ground powders were fumed with the DCM vapor or heated. The MFC processes were accompanied by the transformation between crystalline and amorphous states, which could be confirmed based on the results of XRD patterns in different solid-states. Additionally, it was found that the length of the alkyl chain affected the performance in mechanofluorochromism for PTNn. The dye bearing a short carbon chain showed high-contrast MFC behavior compared with the one bearing a long carbon chain. Moreover, PTN12 and PTN16 bearing long carbon chains could self-assemble into organogels in a certain amount of organic solvents, and gelation-induced emission enhancement was observed during organogelation.

Xanthate was used as an initial reactant to synthesis two kinds of novel xanthate-containing acetic ester additives (HX and OX), and a four-ball machine was used as tribological tester to appraise their tribological behaviors in hydrogenated oil (10cst). The test results indicated that the as-synthesized additives possess good extreme pressure, antiwear and antifriction properties. The shorter carbon chains acetic ester, the better tribological properties the higher sulfur content. The action mechanism was estimated by analysis of the XPS (X-ray photoelectron spectroscopy) and SEM (scanning electron microscope) results of the worn steel ball surface, and the results illustrated that the protective film containing ferric sulfide and ferric sulfate compound was formed on the worn steel ball surface by xanthate acetic ester , and the protective film has good tribological properties.

The opportunistic pathogen, Acanthamoeba castellanii is the causative agent for the sight threatening infection Acanthamoeba keratitis (AK). It is commonly associated with contact lens wearers, and prevalence is increasing at an alarming rate due to an inadequate preventive strategy to protect the lens from this protist. This problem is compounded by the lack of an effective acanthamoebocide, particularly with cysticidal activity in the contact lens solutions. We have used cytotoxicity assays and a variety of biophysical approaches to show that two molecules with tails made of alkyl carbon, alkylphosphocholines (APCs) and quaternary ammonium compounds (QACs) had significant chain-length dependent efficacy against A. castellanii trophozoites, the latter producing death via permeabilization, and DNA complexing. QACs were more effective than APCs and had activity against cysts. Conversely, the QAC with 12 alkyl carbon chain, was non toxic, its presence increased A. castellanii trophozoites biomass and delayed encystation by 96 h. Interestingly, it was unable to induce excystation and increased trophozoite sensitivity to APC16. These results present a mono- and multi-inhibitor management strategy effective against trophozoites and cysts that may be useful for formulating into contact lense cleaning solutions and reducing AK incidence.

Marine dinoflagellates produce remarkable organic molecules, particularly those with polyoxygenated long-carbon-chain backbones, namely super-carbon-chain compounds (SCCCs), characterized by the presence of numerous stereogenic carbon centers on acyclic polyol carbon chains. Even today, it is a challenge to determine the absolute configurations of these compounds. In this work, the planar structures and absolute configurations of two highly flexible SCCCs, featuring either a C69 - or C71 -linear carbon backbone, gibbosols A and B, respectively, each containing thirty-seven stereogenic carbon centers, were unambiguously established by a combined chemical, spectroscopic, and computational approach. The discovery of gibbosols A and B with two hydrophilic acyclic polyol chains represents an unprecedented class of SCCCs. A reasonable convergent strategy for the biosynthesis of these SCCCs was proposed.

The long-chain alkenones in the upper layers of the bottom sediments of ten salt lakes in Southern Siberia were collected as a bio-marker for paleo-limnological studies in the summer 2019. The quantitative and qualitative composition of long-chain alkenones were determined by means of gas chromatography mass spectrometry. Also, the possibility of using this class of compounds as a salt-sensitive bio-marker for paleoclimatic reconstructions in the corresponding regions was assess. The results showed that the extracted alkenones are a mixture of several fractions with different lengths of the carbon chain and the number of double bonds. The alkenone C37:4 fractions positively correlate with the salinity of the studied lakes and can serve as a marker of salinity in paleo-climatic reconstructions.

Several HSO3-functionalized halloysite nanotubes (HSO3-HNTs) were prepared by different methodologies including one-pot organosilylation or sulfonation and two-step organosilylation followed by sulfonation or oxidation. Their physicochemical characterization confirmed the success of HSO3-functionalization with S contents and acidity up to 1.61 mmol S/g and 3.67 mmol H+/g. All HSO3-HNTs were tested as acid catalysts in the esterification of free fatty acids (FFAs) mixture as hybrid feedstock model. Materials obtained from one-pot organosilylation or sulfonation and from two-steps involving sulfonation were the most active showing almost 100% conversion after 3 h: the one obtained by direct sulfonation exhibited the highest TOF (94 h−1) and mass normalized activity (0.08 mol g−1 h−1), whereas that obtained by one-pot organosilylation showed the highest stability and reusability. The increase of FFA carbon chain length led higher conversions, showing the prevalence of inductive effect and absence of steric effects on the esterification mechanism using these new HSO3-HNTs catalysts.

Accurate measuring n-octanol/water partition coefficients (log Kow) of perfluoroalkyl carboxylic acids (PFCAs) using experimental approach has been proven to be very difficult due to their special properties. The ionizable carboxyl groups in PFCAs make their log Kow dependent on pH. In this study, the log Kow values of neutral species of PFCAs (C4≤n≤14) were measured based on reversed-phase high-performance liquid chromatography (RP-HPLC) with the mobile phase pH varying in the range of 1.09–5.00. The relationship between log Kow and retention times was established using some reference compounds (including agrochemicals, polycyclic aromatic hydrocarbons) with known log Kow values, and then validated with alkyl fatty acids, which have similar chemical structures as PFCAs. The apparent log Kow (i.e., log Dow) of the C4–14 PFCAs were calculated based on their retention times using the established model, and they displayed a negative linear relationship with the mobile phase pH in the range of 1.09–4.00. Consequently, the log Dow values were converted to the corresponding log Kow values (1.05–7.19) based on the relationship of log Dow = log Kow + pKa – pH. The log Kow increased with perfluorinated carbon chain length with a greater rate for C4 to C5 PFCAs than for C5–14 PFCAs.

For this study, three corrosion inhibitors with different anionic carbon chain lengths, 1-vinyl-3-methylimidazolium iodide ([VMIM]I), 1-vinyl-3-proplylimidazolium iodide ([VPIM]I) and 1-vinyl-3-butylimidazolium iodide ([VBIM]I) were studied on the corrosion of X70 steel in 0.5 M H2SO4 solution at 298 K by electrochemical measurements, weight loss methods, scanning electron microscope (SEM), FTIR spectra, atomic force microscopy (AFM) and theoretical calculation. Three inhibitors with synergistic effect of iodide ions are mixed-type inhibitors with excellent inhibition efficiency. The order of corrosion inhibition efficiency is: [VMIM]I

Fe3O4/carbon core/shell composites were fabricated via a two-step process. Fe3O4/phenol formaldehyde resin (PFR) core/shell composites were first obtained by hydrothermal method, and the Fe3O4/carb...

Mycobacterium smegmatis is often used to study the different components of mycobacterial cell wall. Mycolic acids are important components of mycobacterial cell wall that have been associated with virulence. Recently, a novel lipid containing mycolic acids has been described in M. smegmatis. However, some uncertainties regarding the structure of this molecule named mycolate ester wax have been reported. The objective of this work was to perform an in depth structural study of this molecule for its precise characterization. Using 1H and 13C NMR spectroscopy, the molecular structure of mycolate ester wax found in M. smegmatis has been elucidated. The characterization was complemented with MS analyses. This molecule is formed by a carbon chain with three methyl substituted olefinic units and a mycolate structure with trans double bonds and cis cyclopropane rings. The present molecular study will facilitate the detection and identification of pentatriacontatrienyl mycolate in future studies by the performance of a simple 1D 1H NMR experiment.

A comparative assessment of the gas barrier properties of polymeric materials of different chemical structure and of composites with organomodified montmorillonite based on polyamide-6 is carried out, with the aim of using them as a barrier layer for polymer hot water pipes.

Hexafluoropropylene oxide dimer acid, also known as GenX, is a poly- and perfluoroalkyl substance (PFAS). PFASs are nonvolatile synthetic substances that can be readily disseminated into the environment during processing and use, making them easy to implement in the soil, drinking water, and air. Compared to other PFASs, GenX has a comparatively short carbon chain length and is expected to have a lower tendency to accumulate in humans; therefore, GenX has recently been used as a substitute to other PFASs. However, the mechanisms underlying GenX action and intoxication in humans remains unclear. In this study, the apoptotic capacity of GenX in human liver cells was investigated. When representative human-derived liver cells (HepG2 cells) were treated with GenX for 12 h, cell viability was reduced, and apoptosis was greatly increased. In addition, GenX increased the generation of intracellular reactive oxygen species (ROS), indicating the induction of oxidative stress in a dose-dependent manner. GenX treatment increased the expression of major apoptosis-related genes relative to the untreated control group. This research indicates that GenX causes apoptosis through ROS mediation in HepG2 cells, which may expand our knowledge of the molecular and toxicological mechanisms of GenX., Graphical abstract Image 1, Highlights • Hexafluoropropylene oxide dimer acid (GenX) can be harmful to the liver. • Through the mediation of ROS, GenX causes apoptosis in HepG2 cells. • GenX activates Bax, caspase 3/9, CHOP, and p53 via the apoptosis. • The intrinsic pathway links GenX mode of action to apoptosis-related stimuli., Poly- and perfluoroalkyl substance; Hexafluoropropylene oxide dimer acid; Oxidative stress; Apoptosis; Liver cells.

In order to understand the microscopic properties of alkylammonium-intercalated vermiculites, molecular dynamics simulations employing the clayff-CVFF force field were performed to obtain the interlayer structures and dynamics. The layering behavior of alkyl chains was uncovered. With the model used in the present study (1.2 e per unit cell), the alkyl chains formed monolayers with carbon-chain lengths of C6, bilayers from C7 to C10, and pseudo-trimolecular layers from C15 to C18. Intermediate states also existed between bilayer and pseudo-trimolecular layer states from C11 to C14. The ammonium groups had two locations: most ammonium groups were located over the six-member rings (~90%), and the rest above the substitution sites (~10%). The ammonium groups interacted with the vermiculite surface through H bonds between ammonium H atoms and surface O atoms. The ammonium groups were fixed firmly on surfaces and, therefore, had very low mobility. The alkyl chains were slightly more mobile. The similarities and differences between alkylammonium-intercalated vermiculites and smectites were revealed. The layering behaviors of alkyl chains were similar in alkylammonium-intercalated vermiculites and smectites: the alkyl chain behavior was controlled by both the amount of layer charge and the carbon chain length. The distributions of ammonium groups, however, were different, caused by the layer-charge distribution in vermiculites being different from that in smectites. The atomic-level results derived in the present study will be useful for future research into and the applications of organo-vermiculites.

The novel classes of acylated phenoxyanilide and thiourea compounds were investigated for their ability to inhibit TEM type β-lactamase enzyme. Two compounds 4g and 5c reveal the inhibition potency in micromolar range and show their action by non-covalent binding in the vicinity of the TEM-171 active site. The structure activity relationship around carbon chain length and different substituents in ortho- and para-positions of acylated phenoxyanilide as well as molecular modelling study has been performed.

Aim. To conduct a comparative analysis of cellular fatty acids composition of isolated bacterial strains belongs to the genus Bacillus, that have pathogenic for insects properties, and some typical representatives of this family. Methods. Fatty acid composition of cellular lipids established by chromatography, gas chromatography-mass spectrometry; calculating the mean, standard deviation and the confidence interval was performed using Microsoft Excel. Results. In the fatty acid composition of all studied strains revealed typical of the genus Bacillus set of fatty acids with carbon chain length from C10 to C18 atoms and particularly high content (more than 60–70% of the total peak area) of the branched (iso- and anteiso- forms) fatty acids has been found for the first time. Conclusions. Fatty acid profiles isolated strains Bacillus sp. significantly similar with collection and typical strains belonging to the species Bacillus thuringiensis.

Surfactants frequently self-assemble in water or in oil, into a large variety of structures, depending on the surfactant and on its concentration. The most common structures will be described in this chapter. Surfactants may also self-assemble in the presence of both oil and water, and structures such as microemulsions are encountered. Self-assembly also occurs in mixed solutions of surfactants and polymers or particles, in solutions of amphiphilic polymers or proteins and in dispersions of particles with functionalized surfaces. A recent survey can be found in the book edited by Nagarajan (2019). Because of their relevance to emulsions, microemulsions, and foams, this chapter will focus on surfactant-based systems and their main features. The common case of surfactant molecules with small polar head groups and hydrophobic carbon chains will be mostly considered. The topic is described in more detail in many books that the reader may consult, for instance, Tanford (1980), Israelachvili (1992), and Evans and Wennerstrom (1999).

Diesel oil-based drilling fluid has been found to be toxic and harmful to environment, mostly due to its cyclic aromatic compound. A lot of research had been done and esters found to be among the promising alternatives, that meets the requirements of a suitable drilling fluid, in terms of technical performance and stability when in wellbore. The study showed that Butyl Acetate is highly sensitive to variation of lime concentration, oil/water ratio, temperature and water salinity, where its plastic viscosity increased dramatically. Butyl Acetate mud system’s performance was compared to palm oil-derived esters with large carbon chains such as Methyl Laurate and Isopropyl Laurate, that are proven to be more stable to alkaline hydrolysis with small increment of plastic viscosities. Commercial base oils that are commonly used in the oil and gas industry such as PETRONAS MG3DF™ and Shell GTL Saraline 185v to were used compare the performance of Butyl Acetate and serve as a control unit, with reference to the API 13B guideline for drilling fluid properties range. Butyl Acetate also showed the highest filtrate loss among all of the oil tested. The larger molecular size of Isopropyl Laurate and Methyl Laurate allows less molecules to pass through the mud cake, compared to the smaller Butyl Acetate molecules which resulted in increase of filtrate loss. The toxicity was observed when all twelve Poecilia sphenops fishes that came in contact with the ester, have died within the first three hours. Even though performance of Butyl Acetate as drilling fluid looks promising, it still poise some problem such as high fluid loss and the cost of raw Butyl Acetate is still considerably more expensive than Diesel.

It is shown for the first time that the Wurtz reaction can be realized by the action of an organic substance (triphenylphosphine) on an alkyl halide (perfluoroalkyl iodide) without the use of metals. It was found that when trying to prepare the bis(3,3′-aminophenyl)(fluoroalkyl)phosphine oxide by four-step synthesis, in the first stage of the reaction of perfluoro-1-iodohexane with triphenylphosphine does not proceed towards the formation of an intermediate quaternary phosphonium salt. Instead, the carbon chain of perfluoroalkyl iodide dimerizes to form perfluorododecane – Wurtz reaction product. We have proposed a new pathway for homocoupling of perfluoroalkylhalides into even-numbered perfluoroalkanes.

Some marine bacteria synthesize docosahexaenoic acid (DHA; C-22) and eicosapentaenoic acid (EPA; C-20) by enzyme complexes composed of four subunits (A-D). We recently revealed that beta-ketoacyl synthase (KSC)/chain length factor (CLF)-like domains in the "C" subunit of DHA synthase catalyzed the last elongation step (C-20 to C-22) even though their amino acid sequences are very similar to those of EPA synthase. To investigate the amino acid residues controlling the product chain length, conserved residues in the KSC/CLF-like domains in DHA synthase were replaced with corresponding EPA synthase residues. Among 12 mutants, two CLF-like domain-mutated genes completely lost DHA productivity and produced trace amounts of EPA when coexpressed with dha-ABD in Escherichia coli, whereas when coexpressed with epa-ABD, they produced the same amounts of EPA as epa-ABCD. These results suggest that the product profiles were subtly controlled by several amino acid residues.

Pseudomonas aeruginosa SG produced 7.06 g/L and 10.32 g/L of rhamnolipids using glucose or soybean oil. Rhamnolipids produced from glucose contained 8 mono-rhamnolipids homologues and 6 di-rhamnolipids homologues with ratio of 61.46%:38.54%. Rhamnolipids produced from soybean oil contained 9 mono-rhamnolipids and 8 di-rhamnolipids homologues with ratio of 58.68%:41.32%. The main homologues produced from soybean oil possessed longer carbon chain of fatty acid. Rhamnolipids produced from glucose decreased surface tension to 26.3 mN/m with critical micelle concentration (CMC) of 50 mg/L; rhamnolipids produced from soybean oil reduced surface tension to 28.1 mN/m with CMC of 60 mg/L. Two rhamnolipids products were thermo-stable and halo-tolerant. Two rhamnolipids products efficiently cleaned oily sludge. Rhamnolipids produced from glucose possessed better surface activity and antimicrobial activity. Rhamnolipids produced from soybean oil exhibited greater emulsifying activity (EI24 = 76.1%) to better reduce oil viscosity. Different substrates make P. aeruginosa produce diverse rhamnolipids with distinct application potential.

Journal of the American Chemical Society, 141 (8), ISSN:0002-7863, ISSN:1520-5126

The objective of this study was to understand how lactate-to-butyrate ratio and substrates concentrations affect the caproate production and product structure. The results showed that a higher butyrate-to-lactate ratio is beneficial to caproate production at low initial lactate concentration. Low pH (5.0) and low substrate concentration (20 mM and 40 mM) effectively decreased propionate production via restrained acrylate pathway, resulting in higher electron efficiency of caproate. With the optimum mole ratio of lactate to butyrate (1:4) and 80 mM initial butyrate concentration, the electron efficiency of caproate reached the maximum (43.10%). Moreover, high butyrate concentration suppressed the production of odd-carbon-number carboxylates while promoting the production of caproate. Compared with the batch operation, the caproate production in semi-continuous operation was enhanced by 3.45 times to 30.91 ± 1.07 mM as the acrylate pathway was successfully inhibited in semi-continuous experiments due to low pH and low lactate concentration.

We performed a carbon-chain molecule (CCM) survey toward four low-mass outflow sources, IRAS 04181+2655 (I04181), HH211, L1524, and L1598, using the 13.7 m telescope at the Purple Mountain Observatory (PMO) and the 65 m Tian Ma Radio telescope at the Shanghai Observatory. We observed the following hydrocarbons (C2H, C4H, c–C3H2), HC2n+1N (n = 1, 2), CnS (n = 2, 3), and SO, HNC, N2H+. Hydrocarbons and HC3N were detected in all the sources, except for L1598, which had a marginal detection of C4H and a non-detection of HC3N (J = 2–1). HC5N and CCCS were only detected in I04181 and L1524, whereas SO was only detected in HH211. L1598 exhibits the lowest detection rate of CCMs and is generally regarded to be lacking in CCMs source. The ratio of N(HC3N/N(N2H+)) increases with evolution in low-mass star-forming cores. I04181 and L1524 are carbon-chain-rich star-forming cores that may possibly be characterized by warm carbon-chain chemistry. In I04181 and L1524, the abundant CCCS can be explained by shocked carbon-chain chemistry. In HH211, the abundant SO suggests that SO is formed by sublimated S+. In this study, we also mapped HNC, C4H, c–C3H2, and HC3N with data from the PMO. We also find that HNC and NH3 are concentrated in L1524S and L1524N, respectively. Furthermore, we discuss the chemical differences between I04181SE and I04181W. The co-evolution between linear hydrocarbon and cyanopolyynes can be seen in I04181SE.