Search

4-Nonylphenol (4-NP) is a para-substituted phenolic compound comprising a straight or branched carbon chain group while branched 4-NP consists of 211 possible structural isomers. NP is recognised as an environmental pollutant and exists ubiquitously in both the environment and in food. 4-NP, especially branched 4-NP, has been shown to have the potential role of endocrine disruptor and xeno-oestrogen. Moreover, different NP isomers also exhibit different oestrogen-like activities. Recently, it was reported that the isomer-specific profile of 4-NP in foodstuffs varies greatly between and within food groups. Hence, risk assessment based on total branched 4-NP cannot reflect dietary risk. This study reviews the analytical methods applicable to conduct an isomer-specific analysis of 4-NP and its occurrence in foodstuffs. Lastly, research gaps are identified for future research.

The long carbon chain monomer modified polyacrylate latex was successfully prepared by semi-continuous seeded emulsion polymerization. In this work, methyl methacrylate and butyl acrylate were used...

The 2Πg←X2Σu+ electronic spectrum of C5+ in the gas-phase with origin band at 513nm is reported following experiments in a cryogenic ion trapping instrument. Buffer gas-cooled C5+ ions, generated by laser vaporisation of graphite, were investigated using two action spectroscopy approaches. Laser-induced dissociation of weakly bound C5+−Hen complexes synthesised in the trap reveal a linear dependence of the absorption energies on n allowing prediction of those of the bare ion C5+. These results are confirmed in two colour experiments on C5+, by monitoring fragmentation into the C3+ + C2 product channel. The data are supplemented with high-level electronic structure calculations which support the assignment of D∞h symmetry to the ground electronic state. These laboratory results provide the requisite data needed for spectroscopic detection of this structure in terrestrial and extraterrestrial environments.

The rotational spectra of the singly substituted carbon-13 isotopic species of six sulphur-terminated carbon chains have been detected between 5 and 40 GHz using a supersonic discharge jet source i...

Four compounds from 3FmHPhF homologous series of chiral smectogenic fluorinated compounds (m = 2, 4, 5, 6) were studied by frequency domain dielectric spectroscopy, electro-optic measurements, X-ray diffraction and differential scanning calorimetry. Values of the relaxation time and dielectric increment of relaxation processes versus temperature and bias field were determined. The temperature-dependent tilt angles, spontaneous polarisations, switching times, rotational viscosities, and average intermolecular distances and correlation lengths within smectic layers were obtained. Experimental results were supplemented by density functional theory calculations of isolated 3FmHPhF molecular geometries, and the relationship between the molecular structures and the transverse component of their dipole moments was studied for the mesogens with m = 2, 4, 5, 6, 7. The results are discussed in terms of the length of the CmH2m flexible carbon chain of the homologues.

Hydrophobic long carbon chains (C16) were grafted onto the main chains of Xanthan Gum by etherification under the ordered conformation of Xanthan. Rheology and pyrene fluorescence spectroscopy expe...

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...

A simple and effective chemical method based on Mannich reaction, sulfonation, and acylation was adopted to anchor the hydrophilic sulfonic groups and lipophilic long carbon chains onto alk...

The aim of this study was the formulation composition and characterization of the liquid crystal (LC) emulsion. First, influences of formulation composition on preparation of LC structure were studied, including the aliphatic alcohols with different carbon chain length, the liquid oils with different polarities, the sodium chloride, and the polygons. The results showed that fatty alcohols which is closer to the hydrophobic group of the emulsifier, little liquid oil, and little polyols were conducive to form LC structure. Then, the application performance of LC structure emulsion was studied. The results showed that compared with the conventional structure emulsion, the LC structure emulsion had more excellent moisturizing property, slow release effect, and the promoted penetration effect.

In this study, decomposition products of glycidyl palmitate (GP) of fatty acids heated at high temperature such as deep frying were investigated. When GP and tripalmitin (TP) were heated at 180 and 200 °C, they were decreased with heating time. The weight of GP was less than that of TP, although both GP and TP were converted to polar compounds after heating. The decomposition rate of GP was higher than TP. Both GP and TP produced considerable amounts of hydrocarbons and aldehydes during heating. Aldehydes produced from GP and TP included saturated aldehydes with carbon chain length of 3–10, while hydrocarbons consisted of carbon chain length of 8–15. It was observed that major hydrocarbons produced from GP during heating were pentadecane. Moreover, the level of carbon dioxide (CO2) released from GP was higher than that of TP. It was suggested that fatty acids in GE might be susceptible to decarboxylation. From these results, GP might be quickly decomposed to hydrocarbons, aldehydes and CO2 besides polar compounds by heating, in comparison with TP.

In order to find the rules of selecting organic desulphurization additives, eight kinds of organic acids with different pKa values, carbon chain lengths, and functional groups were discussed. As a result, three screening rules can be obtained for selecting organic desulphurization additives: firstly, the pKa value of organic acid should be between 4.21 and 4.83; then short carbon chain was better for SO2 removal; finally, organic acid with functional group was better than linear chain. Moreover, organic acids increased the desulphurization efficiency by promoting the oxidation of SO32− and accelerating the gas–liquid mass transfer and dissolution rate of SO2.

An efficient and reproducible microwave-assisted synthesis of dialkyl ω-azidoalkylphosphonates via nucleophilic substitution of the appropriate dialkyl ω-bromoalkylphosphonates by sodium azide in water or dimethylformamide (DMF) as solvent has been developed. This process has been optimized for batch reactors. The target, structurally diverse dialkyl ω-azidoalkylphosphonates with different steric hindrance around the phosphonato groups and containing unbranched side carbon chains of different lengths (n = 2–6), has been obtained in moderate to high yields (39–87%).

Spatial changes in the concentrations and compositional patterns of aliphatic hydrocarbons in sediments of the Forcados River in the Niger Delta, Nigeria, were studied. The concentrations and identities of the aliphatic hydrocarbons were determined by means of gas chromatography with flame ionization detection (GC/FID). The concentrations of aliphatic hydrocarbons in the Forcados River sediments ranged from 16.2 to 603.3 µg/kg, which were below the UNEP (United Nations Environment Programme) recommended limit of 10,000 µg/kg. The carbon preference index (CPI) and pristane/phytane ratios indicated that the major source of hydrocarbon pollution in the sediments was of petrogenic origin. The average carbon chain length (ACL) was used to identify the chemical environment. The ACL values were constant at 28 in most of the sampling stations, except for the sampling stations of Yobebe (27.41), Bomadi (26.24), and Abare (27.12), where they were lower due to petroleum contamination in the study area. The r...

The differences of thermodynamics energies from the pure phase to a solution were used to predict the solubility properties of acidic phosphorus-containing rare-earth extractants. Four solvents, namely, tributylphosphate, n-dodecane, toluene, and n-octanol were used. The thermodynamic cycle of the implicit solvation model and the structure model with short carbon chains were used. The relationship obtained by simulation of the solubility properties and extractant structures agreed qualitatively with reported experimental results. These results provide guidance for the design of new efficient extractants.

Reverse flotation of Pingsuo thermal coal was investigated and it turned out that a large amount of DDA-HCL (dodecylamine hydrochloride) was needed in this process. Two fatty acids (dodecanoic acid and oleic acid) of different carbon chain lengths emulsified by DDA-HCL were used to compare with DDA-HCL in the experiments. Experimental results showed that the two emulsions had stronger collectivity than DDA-HCL. Dodecanoic emulsions had higher selectivity than OA (oleic acid) emulsions. The application of dodecanoic emulsions can obtain a lower ash content of the concentrate than DDA-HCL at the same collector dosage. And it can reduce DDA-HCL consumption greatly under the same concentrate ash content. Reverse flotation results of the two emulsions were also compared. The results indicated that the selectivity of dodecanoic emulsions dropped sharply when the amount of substance ratio of DDA-HCL and dodecanoic acid was less than 1:1.

Effects of varying concentrations of 1,2-ethanediol, 1,2-butanediol and 1,2-hexanediol (glycols) on the micellisation and thermodynamic properties of sodium dodecyl sulphate (SDS) were studied at temperature range 288–313 K by conductometry method. Critical micelle concentration (CMC) of SDS increased in 1,2-ethanediol but decreased in the longer carbon chain glycols in the order: 1,2-hexanediol

Spectroscopy of carbon particles, fullerenes, and carbon chain molecules was the subject of a considerable part of my research work, as described in this article. In almost all cases, there existed a tight connection to problems in astrophysics and astrochemistry, aiming at a better understanding of interstellar matter. The bulk synthesis of fullerenes was a by-product of these efforts.

The structure of polydiacetylene (PDA) supramolecules offers carboxylic acid-terminated alkyl side-chains around a π conjugated polymer backbone. Exposure of these supramolecules to alkylamines induced disruption of the conjugated PDA backbone via intercalation as revealed by a colorimetric/fluorometric response. This response is demonstrated to be dependent on the length of the alkylamine, offering a new view on intercalation in PDA systems with respect to supramolecules. It is found that this critical carbon chain length of alkylamine required to induce a colour change response must be greater than the alkyl side-chain length of PDA in order to interact with the conjugated backbone. Intercalation of longer species is also found to induce supramolecule aggregation resulting in destabilised PDA suspensions.

In our efforts to understand how various dietary factors can influence the risk and progression of chronic disease, much recent research has focused on phytochemicals. Phytochemicals are defined as nonessential nutrients found in plant-based food, many of which have been established as bioactive and thus may affect human health. The largest group of phytochemicals is the polyphenols, comprised principally of the flavonoids, which are characterized chemically by two benzene rings joined by a linear carbon chain. Evidence from observational studies indicates that regular consumption of foods containing flavonoids may reduce the risk several chronic conditions, including neurodegenerative diseases, atherosclerosis, and certain forms of cancer. These results have generated considerable interest in flavonoids, although much basic information about their nutrient characteristics in humans remains limited, e.g., their bioavailability and metabolism, interactions with other dietary factors, mechanisms of action, and intakes associated with specific health outcomes. Although flavonoids are commonly defined as dietary antioxidants and their putative health benefits commonly attributed to this mechanism, it now appears their principal actions are mediated in vivo via other biochemical and molecular pathways.

Microbial-derived volatiles are ubiquitous in the environment and actively engaged in bio-communication with other organisms. Recently, some volatile-producing endophytes (VPEs), cryptic fungal symbionts persisting in healthy plant tissues, have attracted great attention due to their strong antibiotic activity or production of carbon chains that are identical to many of those found in petroleum, while other fragrant volatiles can be used in the flavoring industries. From an application-oriented and biotechnological point of view, these findings show significant promise for sustainable development of agriculture, forestry, and industry, especially in the control of fruit postharvest diseases, soil-borne pathogen management, and bio-fuel production. In comparison, the ecological importance of VPEs has only rarely been addressed and warrants further exploration. In this review, we summarize the current knowledge and future directions in this fascinating research field, and also highlight the constraints and progresses towards commercialization of VPEs products.

ESI-MS spectra were recorded with a FIA-MS system under CID conditions for 19 polyhydroxy carboxylic acids to assess the analytical selectivity of single quadrupole MS and to evaluate its suitability for the qualitative identification of the target compounds. Suited ESI operation conditions were defined for several sugar acids and their lactones and the pH dependence of the respective acid-lactone conversion was investigated. Besides the common neutral mass losses of H2O and CO2 specific mass losses, presumably belonging to the release of small carbon chain units, were established for isocitric and gluconic acids. A product ion with m/z 75 was part of the MS spectra of all aldonic acids, potentially indicating this structural subgroup of sugar acids. The spectra of other sugar acids and of tartaric, isocitric and shikimic acids had a product ion with m/z 73 in common. The results reveal that the CID mass spectra of several hydroxy acids show characteristic product ion patterns suited for a selective analy...

Spectroscopic characterisation of carbon chains and ions has been motivated by a general interest in understanding the electronic structure and properties and also due to their prominence in astrochemistry, combustion processes as well as molecular electronics. Various experimental and theoretical approaches have been successfully implemented over the years towards realising this goal. In the current review, we have tabulated the experimentally available data on the excited electronic states of carbon chains and derivatives containing H, N, O, S and metals.

In the present work, we assessed the relationship between alkyl carbon chain length and ocular irritation potentials using the hen's egg test-chorioallantoic membrane (HET-CAM) and bovine corneal opacity and permeability (BCOP) assays using 5 commercial alkyl polyglucoside surfactants with different compositions of alkyl chain lengths (C(6)-C(16)). With HET-CAM, there was a good correlation between the proportion of C(10) alkyl polyglucoside and the eye irritation potential Q score (r(2) = 0.912, p = .011). There were no significant differences between the proportion of C(10) alkyl polyglucoside and corneal opacity in BCOP assays; however, there was a relatively high positive correlation between the proportion of C(10) alkyl carbon chain lengths and corneal permeability (r(2) = 0.736, p = .063).

There is a common concept in life: large and complex molecules result from the synthesis of units that are later joined together. Mankind learned this principle and employed it to develop language, culture, and technology. This same principle is applied in the petrochemical industry by fractionating the fossilized carbon chains into small molecules and then polymerizing them in order to develop synthetic polymers, which are much more flexible, resistant, and durable than natural polymers. Recent developments in molecular biology have opened the possibility of modifying organisms in order to create new biosynthetic routes for the production of monomers that would fit the biggest challenge in modern society: the production of high quality polymers from renewable feedstocks. This review focuses on the latest advances in molecular biology and the new knowledge and technologies that enable the possibility of converting cells into efficient and sustainable chemical reactors. The first examples of this technolog...

We introduce a congener-specific numbering system for the C4 through C8 perfluorinated homologue groups of alkyl sulfonates, carboxylates, telomer alcohols, olefins, and acids, and their derivatives. Increasing length of the carbon chain beyond C3 leads to a corresponding rapid increase in the number of potential isomers (C4 = 4, C5 = 8, C6 = 17, C7 = 39, and C8 = 89 congeners). There is a need for clear and unambiguous chemical shorthand to ensure accuracy and consistency in the future perfluorinated alkyl substance (PFA) literature, and to correct previous misconceptions that may have restricted research efforts into developing full-congener PFA analysis. If adopted by the research community, introduction of a numbering system at this relatively early stage of investigations into the congener-specific analysis, environmental behavior, and toxicology of PFAs would not require an arduous and difficult reassignment of historical structures and naming conventions presented in the prior art. Many PFA congeners are chiral, necessitating a consideration of their enantiospecific environmental behavior and toxicology.

The reaction of 7‐mercapto‐4‐methylcoumarin (4) with 1‐mono‐ and 1,1‐dimethyl propargyl alcohols in H3PO4 afforded the corresponding β‐(7‐coumarinthio)ketones with a rearrangement of the carbon chain of propargyl. A possible mechanism of this rearrangement was proposed.

A series of pure linear carbon chain alkylnaphthalenes, including mono-hexylnaphthalene, mono-octylnaphthalene, mono-decylnaphthalene, mono-dodecyl-naphthalene, di-hexylnaphthalene, and di-octylnaphthalene, were prepared via alkylation reaction of naphthalene with 1-bromoalkane catalyzed by AlCl3. The purity of all products was > 98%. The structures and contents of the main components in each alkylnaphthalene product were identified and determined by GC/MS and are presented in detail in this paper.

1-Phenylalkane sulfonates (with carbon chains of 12, 14, and 16) with high purity were prepared through a comparably simple way to study dynamic interfacial tensions against crude oil. During the investigation of dynamic interfacial tensions, interfacial tension minima were observed and the reason thereof was given. The effect of surfactant concentration on dynamic interfacial tensions was also studied to find that NaOH concentration can also affect the time reaching minima through affecting the activity of surfactant. For the sake of simplicity, the concept of “appearance” interfacial activity was proposed.

The linking of segments, which have a tendency to phase separate at suitable temperatures, by covalent bonding has been employed in the synthesis of inorganic-organic hybrids. This approach can be utilised to tailor the stability range and the properties (eg viscosity) of liquid crystal materials. Research into such materials has focused strongly on the combination of calamitic moieties and silicones, however the introduction of a third phase separating segment, of which perfluorinated carbon chains are a good example, is an attractive area of research. In this paper we will report the synthesis and characterisation of materials incorporating a range of calamitic mesogens. These are attached either terminally or laterally to flexible linear chains containing alkyl and siloxane units fused to a central perfluorinated chain. The phase behaviour of the investigated materials is characterised by nematic and smectic phases with transition temperatures close to ambient. The size of the different linear units wa...

The interfacial tension (IFT) of 1 M solutions of N,N-dialkyl amide in n-dodecane against water and nitric acid has been measured at 303K. Ten amides, namely, dibutyl hexanamide (DBHA), diisobutyl hexanamide (DiBHA), dibutyl octanamide (DBOA), dihexyl hexanamide (DHHA), dibutyl dodecanamide (DBDA), di n-octyl butanamide (DOBA), diisooctyl butanamide (DiOBA), di n-octyl isobutanamide (DOiBA), di n-hexyl octanamide (DHOA), and di n-octyl hexanamide (DOHA) were synthesized and used. The effect of concentration of DOHA on IFT against 3 M nitric acid was also studied. It was observed that the introduction of branching in an amide on either the acyl or the nitrogen side increases the IFT over its straight chain analogue, as in the case of DiOBA, DOiBA, and DiBHA. Increasing the carbon chain length on the acyl side, keeping the total carbon number constant, was found to increase the IFT considerably. Increasing the concentration of the amide resulted in a decrease in the IFT values, due to the lowering of the concentration of hydrophobic diluent. An increase in the uranium loading of the organic phase in the case of 1 M DOHA, was found to increase the IFT.

Medium chain aliphatic alcohols (C8-C12) and methyl or propyl esters of medium chain fatty acids (C8-C12) enhanced the permeation of 6-carboxyfluorescein (6-CF) and indomethacin (IND) through excised rat skin. The enhancing effects of the aliphatic alcohols for 6-CF and IND decreased with the increase in carbon chain length. The dependence on the carbon chain length was different from that exhibited by medium-chain fatty acids previously reported. In the case of fatty acid esters, the enhancing effects were lower than those of aliphatic alcohols and fatty acids. The relationship between the enhancing effects and the total number of carbon atoms in the esters was different for 6-CF and IND. The dependence on the total number of carbon atoms was similar to that in the aliphatic alcohols for 6-CF, and greater effects were observed in the shorter esters. On the other hand, no definite trends were observed for IND. Although the relationships between the structure and skin permeation-enhancing effect of the aliphatic alcohols and fatty acid esters used in this study are not yet fully understood, they are possible candidates as permeation enhancers for hydrophilic and lipophilic drugs. Further experiments, including examination of the location and environment of the lipophilic carbon chain and hydrophilic groups of such enhancers in the stratum corneum, are needed to optimize transdermal delivery systems containing them.

It is shown that bromoacetyl bromide can be utilized for the selective cleavage of ethers and acetals in high yields. With cyclic ethers and acetals as starting materials, cleavage products are produced with two strategically positioned bromo substituents which may be exploited for selective extention of the carbon chain.

All diastereomeric aldo-D-pentoses and -D-hexoses were reacted with Meldrum's acid (2,2-dimethyl-1,3-dioxane-4,6-dione) under basic conditions. A protocol was applied and optimized which was originally reported by J. A. Galbis Perez et al. in 1990. In every case formal substitution of the anomeric hydroxyl against a carboxy-methylene group occurred thus elongating the carbon chain of the parent aldose by a C2 fragment. Products are mainly 3,6-anhydro-2-deoxy-aldono-1,4-lactones in which the lactone rings are annulated to a furanoid system. However, D-mannose and D-lyxose also gave pyranoid 3,7-anhydro-1,4-lactones. Intermediates are unsaturated open-chain 1,4-lactones (butenolides) which in some cases could be isolated as by-products. Epimerisation at C-2 of the parent aldose occurred at least partially in most reactions. The products and their acetylated derivatives were characterized by 1H and 13C NMR spectroscopy. A proposed mechanism of this reaction is supported by additional experimental ev...

The excess volumes of 1-pentanol+, 1-hexanol+, 1-heptanol+, 1-octanol+, 1-decanol+ and 1-dodecanol + heptane mixtures were evaluated at 298.15 and 308.15 K from the density data. The excess volumes were found to decrease with the increase in the carbon chain length of alcohol molecules. The temperature coefficient for the excess volumes was also observed to show a decreasing trend from 1-pentanol + to 1-dodecanol + heptane mixtures. The excess volumes were also calculated by combining the individual physical and chemical contributions, evaluated by combining an association model with Flory's free volume theory. Reasonable agreement between the experimental and calculated excess volumes for all the mixtures at 298.15 and 308.15 K was noted.

Symmetric dialkylphosphoryl-S-alkanediyldiisothiouas (RO)2P(O)NHC(=NH)S(CH2)n SC(=NH)NHP(O)(OR)2 (I, R = isopropyl; n = 2–5) have potential coordination sites involving O, P, N and S as donors atoms. For their synthesis, common two-phase reactions between the corresponding diisothiourea derivatives and diisopropyi phosphonate were unsuccessful. Herein we describe a new synthesis for such compounds using diisopropyl chlorophosphonate. Two new bis-phosphorylated alkanediyldiisothioureas with increasing carbon chain (I; n = 3, n = 5) were prepared by this method.

This review introduces the present status of interstellar chemistry and shows why various carbon-chain molecules occupy a key position among hundred or more interstellar molecules so far identified. Then, several series of sulfur-bearing carbon-chain molecules such as C n S, HC n S, C n S2, C n OS, and C n O2 are reviewed especially by paying attention to their generation and spectroscopic characterization in the laboratory.

The synthesis of new types of organic-inorganic polymers (urethane-phosphazene polymers) from cyclotriphosphazenes and the use of polyorganophosphazenes in the surface modification of organic polymers such as Poly(viny alcohol) (PVA) and poly(ethylene-co-vinyl alcohol) (EVOH) have been investigated. In both cases, the goal of the studies was to combine the usual advantages of the organic polymers and some of the properties of phosphazenes, namely mechanical properties, thermal stability, light-heat and fire resistance by incorporating them into the carbon chain or by superficial grafting.

The construction and investigation of photoresponsive and redox-active supramolecular systems with acetylenyl (polyyne) and cumulenic sp hybridized carbon chains (Cn) are reported here. Novel types of one-dimensional rigid molecular rods and macrocyclic molecular squares with controllable and yet fixed chain lengths or cavity sizes are explored. Such systems will have the desired features such as synthetic accessibility, coordination versatility, rigidity, directionality, photostability, electronic conductivity, controllable distances between donors and acceptors, and controllable cavity sizes in macrocyclic molecular squares. These features are extremely important to the future applications of these new rigid supramolecular systems in molecular photonic and electronic devices, light-energy conversion, molecular recognition, and host-guest chemistry. In addition to the exploration of synthetic features, the solution state redox characteristics and molecular photophysics of the metal-containing su...

In this work attention focuses on mercaptotriazinone derivatives, which do not paint polymers and are fairly effective stabilizers of thermooxidative degradation of carbon chain polymers, in particular, of an isoprene rubber.

The extraction of lincomycin with long-chain alcohols as solvent was studied. The experimental results indicated that the power of n-alkyl alcohols for the extraction of lincomycin depends mainly on the molarity of alcohols in solvent used. For alcohols with short carbon chain, the steric hindrance of alkyl groups in alcohols with different structure has only little influence on the extraction of lincomycin. The chemistry of extraction of lincomycin with alcohols as solvent was discussed.

The locations of double bonds and the linearity of each carbon chain in 5-alk(en)ylresorcinols present in rye and wheat whole flour were determined from collision-activated dissociation (CAD) spectra by tandem mass spectrometry. Among the determined alk(en)ylresorcinols, eleven alkenylresorcinols (C17 to C23) and four alkadienylresorcinols (C19 to C25) had not been previously identified. In this study, we found that identification of a radical-anion fragment peak due to a simple allylic cleavage on the methyl side was essential for determining the locations of double bonds in positionally isomeric alkenylresorcinols. In addition, an analysis of the CAD spectra of lithium-adduct cations as precursor ions was useful for determining the locations of the homoconjugated (Z,Z)-diene group in alkadienylresorcinols.

Ganglioside GM3 and KDN-ganglioside GM3, containing hexanoyl, decanoyl, and hexadecanoyl groups at the ceramide moiety have been synthesized. Selective reduction of the azido group in O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-α-D-galacto-2-nonulopyranosylonate)-(2→3)-O-(2,4-di-O-acetyl-6-O-benzoyl-β-D-galactopyranosyl)-(1→4)-O-(3-O-acetyl-2,6-di-O-benzoyl-β-D-glucopyranosyl)-(1→1)-(2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol (1) and O-(methyl 4,5,7,8,9-penta-O-acetyl-3-deoxy-D-glycero-α-D-galacto-2-nonulopyranosylonate)-(2→3)-O-(2,4-di-O-acetyl-6-O-benzoyl-β-D-galactopyranosyl)-(1→4)-O-(3-O-acetyl-2,6-di-O-benzoyl-β-D-glucopyranosyl)-(1→1)-(2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol (2), coupling with hexanoic, decanoic, and hexadecanoic acids, O-deacylation, and de-esterification gave the title gangliosides GM3 (11→13) and KDN-GM3 (14→16) in good yields. On the other hand, O-deacylation of 1 and subsequent de-esterification gave 2-azido-sphingosine conta...

Self-assembled (SA) and Langmuir-Blodgett (LB) monolayers of nonadecanoic acid on the surface of silver have been investigated by reflection-absorption Fourier transform infrared spectroscopy. The molecule was chemisorbed on silver very favorably as nonadecanoate after losing the carboxylic proton. Although both the LB and SA monolayers consisted of Fully extended trans zigzag molecular chains assembled in a crystalline state, the carbon chains of SA monolayers seemed to assume a more perpendicular stance with respect to the silver surface than those of LB monolayers.

Carbon chain extensions of 5-O-tert-butyldimethylsilyl-1,2-O-isopropylidene-α-D-gluco-and β-L-ido-hexodialdose with ethoxycarbonylmethylenetriphenylphosphorane or triethyl phosphonoacetate gave the corresponding α,β-unsaturated octuronic esters, the (E)/(Z)-ratios of which strongly depending on the reagent used as well as the starting material. After conventional reduction of the ester moieties the corresponding O-acetyl protected allylic alcohols were subjected to osmylation leading to the respective 1,2-O-isopropylidene protected octoses, which were subsequently converted to some previously unreported octitols. Unambiguous structure proofs, demonstrating the validity of Kishi's empirical rule for the stereochemical outcome of the osmylation reactions reported, were obtained from the NMR spectroscopic features of these products as well as regiospecific chemical degradations to corresponding known heptitols.

Discriminant analysis can be used to (1) find criteria to separate observations into groups and (2) to optimally assign a new observation to its correct group. It is rather exploratory in nature especially when causal relationships are not known. Twenty four selected organics were tested as corrosion inhibitors and both physical and structural features were encoded as criteria for discrimination. In addition, a narrower set of twelve nitrogen containing compounds was also studied. In both cases the carbon chain length was an important uncoded criterion. The physical factors such as boiling point, molecular weight, pKa, and molecular area were not as important as some of the structural parameters.

Condensation of furanoid as well as pyranoid aldonolactones with organozinc reagents obtained from different haloalkanoates and the zinc/silver-graphite surface compound gave in high yield carbon chain extended 3- or 4-ulofuranos- (or -pyranos)onates.

Comprehensive studies of photoinduced addition of phosphorus trihalides to unsaturated compounds, i.e. alkenes, alkynes, alkadienes, and enynes, were carried out. The addition of phosphorus trihalides to unsaturated C‒C bonds is proved to be a radical chain process, the total reaction irate increasing with the increase of electron density on the unsaturated C‒C bond. The photoinduced reaction of alkenes with PRr3 goes via Br atom attack on the least substituted C-atom of an unsaturated C‒C bond and mainly results in the formation or dibromophosphines with a phosphorus atom in the second position of the carbon chain −(1–2)-addition. In the case of polysubstituted alkenes an alternative direction of the reaction is realized, namely the photoinduced substitutional dibromophosphination to alkyl group. The reaction with alkynes results only in the formation of the products of (1–2)-addition. The Regioselectivity of the addition of phosphorous trihalide fragments to the substrate containing a heteroato...

Methods have been developed for air sampling of gaseous tertiary amines on solid sorbents. Sampling was performed at three different air levels and at 20 percent and 85 percent relative air humidity, respectively. Desorption was carried out by solvent extraction prior to high-resolution gas chromatographic analysis with flame ionization or nitrogen-phosphorus detection. Seven amines, differing in the length and shape of the carbon chains, were selected for the study and divided into three groups. The members of the first group, consisting of dimethylethylamine (DMEA), methyldiethylamine (MDEA), and triethylamine (TEA) were collected using charcoal tubes and desorbed with 5 percent ethanol in dichloromethane. The amine air levels were 1, 10, and 50 ppm. The recoveries of these amines were 92–100% (n = 6, RSD = 1–4%). Storage studies (5 days at room temperature followed by 9 days in a freezer) showed recoveries of 87 percent (DMEA), 89 percent (MDEA), and 82 percent (TEA). Determination of DMEA in ...

A simple method for extending the carbon chain via the coupling of alkyl or aryl halides has been developed. The versatility of this reaction has been demonstrated by symmetrical and unsymmetrical coupling of alkyl, alkenyl or alkynyl halides.

Over forty 4-alkoxyphenyl 4-alkoxybenzoates incorporating an olefinic double bond in one carbon chain and an optically active centre in the second (methyl branched) chain have been prepared. The effect of chain length and the position of the chiral centre on the liquid crystal transition temperatures of the esters has been investigated systematically. Apart from one important exception the double bond was maintained in a terminal position of the carbon chain. Several of the new esters exhibit an enantiotropic chiral smectic C mesophase at and just above room temperature.