Alkyl Ester Side Chains Research Articles

Penithoketone and Penithochromones A-L, Polyketides from the Deep-Sea-Derived Fungus Penicillium thomii YPGA3.

Twelve new polyketides, including a naphthoquinone derivative, penithoketone (1), and 11 chromone derivatives, penithochromones A-L (2-12), together with three known compounds (13-15) were isolated from the deep-sea-derived fungus Penicillium thomii YPGA3. The structures of the metabolites were elucidated based on extensive analyses of the spectroscopic data, and the configuration of 1 was resolved by quantum chemical calculations of NMR shifts and ECD spectra and comparisons to experimental data. Compound 1, containing a naphthoquinone-derived moiety substituted with a butenolide unit, represents a new modified naphthoquinone skeleton. Interestingly, the 5,7-dioxygenated chromone derivatives 2-13 possessed different alkyl acid or alkyl ester side chain lengths, and those with side chain lengths of seven carbon atoms were discovered from nature for the first time. The metabolites were evaluated for their cytotoxicity against four cancer cell lines; compounds 1 and 15 were found to be active, with IC50 values ranging from 4.9 to 9.1 μM.

Direct C-H coupling polymerization of asymmetric monomer: Synthesis and properties of regioregular poly(alkyl thiophene-3-carboxylates)

A series of poly(alkyl thiophene-3-carboxylates), herein referred to as poly(3-alkylesterthiophenes) (P3ET) (P1-P6) with high head-to-tail (HT) coupled regioregularity up to ∼92% were synthesized by a direct CH coupling polymerization (DCHCP). The substitutions with various alkyl ester side-chains on the 3-position of the thiophene ring were performed by changing the length and size of alkyl groups, with a view to investigate the role of the alkyl ester side chain on DCHCP reaction as well as on the crystallinity, optical and electrochemical properties of these resultant polymers. It was found that the longer and bigger size alkyl ester side chains on 3-position of thiophene monomers, the higher HT regioregularity of the corresponding polymer products. X-ray diffraction (XRD) measurements manifested that all polymers (P1-P6) existed in not highly ordered state in solid films especially in the π-stacking direction. Red shift of the UV–Vis absorption maxima of the resultant polymers in the film state confirmed more effective electron delocalization along the polymer chain than that in solution state. Cyclic voltammetry (CV) study indicated that the introduction of 3-alkyl ester side chain on the thiophene ring lowered the products' highest occupied molecular orbital (HOMO) energy level and enhanced their electrochemical band gaps significantly in comparison with the corresponding HT regioregular poly(3-alkylthiophenes).

Effects of Na‐sulfopropyl groups on the mechanical properties and morphology of polystyrene‐co‐methacrylate ionomers

ABSTRACTThe dynamic mechanical properties and morphology of poly(styrene‐co−3‐sulfopropyl sodium‐methacrylate) SSPMANa ionomers were investigated. It was found the increasing rate of ionic moduli of the SSPMANa ionomer was very low, and the cluster Tg of the ionomers remained more or less constant with increasing ion content. A well‐developed SAXS peak was seen for low ion content SSPMANa ionomers and the peak position changed slightly with ion content. Thus, it was suggested that the presence of the alkyl ester side chains made the ion pairs form multiplets more easily at their prevalent distances, and the small‐agglomerated multiplets were dispersed in the polymer matrix relatively evenly. The interpretation of ionic moduli using a number of theories implied that the multiplets and clusters acted as effective crosslinks and filler particles, respectively, and the size and shape of the clusters were irregular. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 1043–1053

Surface properties and liquid crystal alignment behavior of poly(2-hydroxyethyl methacrylate) derivatives with alkyl ester side chains

Poly(2-hydroxyethyl methacrylate) derivatives with amphiphilic side chains composed of polar ester and non-polar alkyl groups (PHEMA#C, #=9, 11, 13, 15, and 17), where # is the number of carbon atoms in the alkyl side groups, were synthesized. In this paper, the influence of ester and alkyl groups on the molecular structure and wettability of the polymers were studied through varying # in the alkyl side groups. PHEMA#Cs with relatively longer alkyl side groups (#⩾15) show bilayer lamellar structures with well aligned side chains giving rise to the very low surface energies, calculated from advancing contact angles, in the range of 22.7–22.8mN/m. In contrast, PHEMA#Cs with shorter alkyl side groups with #⩽13 have disordered structures on the polymer surfaces and stick–slip behavior was observed when water was used as the test liquid for the advancing contact angle measurements. Furthermore, the alignment behavior of nematic liquid crystal, 5CB on the PHEMA#C films could be correlated with the molecular structure and wettability of the polymers.

Dietary Phenolic Acids and Derivatives. Evaluation of the Antioxidant Activity of Sinapic Acid and Its Alkyl Esters

The action of sinapic acid and its alkyl esters as potential antioxidants has been investigated. For this purpose, a series of sinapic acid ester derivatives was synthesized and their antioxidant activities were evaluated using distinctive analytical methods, namely, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and FRAP UV-vis methods and differential scanning calorimetry. The electron-donating activity and lipophilicity of these phenolic compounds were also evaluated. From the overall results it was concluded that alkyl ester sinapates (linear alkyl esters) present almost the same antioxidant activity, albeit slightly lower, exhibited by the parent compound (sinapic acid). Furthermore, the addition of an alkyl ester side chain has a positive effect on the partition coefficient of sinapic acid, improving its utility as an antioxidant in a more lipophilic medium. The data on the antioxidant activity obtained by different analytical methods correlated well with each other and have revealed interesting antioxidant data of alkyl esters of sinapic acid.

Spontaneous Nanoaggregate Formation of Amphiphilic Poly(amide acid)s in Water

Abstract Alicyclic poly(amide acid) triethylammonium salts having alkyl ester side chains spontaneously self-assembled to form nanoaggregates in water. The nanoaggregates of poly(amide acid)s encapsulated a hydrophobic guest molecule, Nile red, within their apolar microenvironment. The size of the aggregates and the critical aggregation concentration (CAC) were considerably affected by both side chain length and Mw, of the polymers.

Structure−Property−Activity Relationship of Phenolic Acids and Derivatives. Protocatechuic Acid Alkyl Esters

The esterification of hydrophilic phenolic antioxidants is an efficient approach to enhance their solubility in apolar media. Herein, structure-property studies on the antiradical activity of a series of protocatechuic acid alkyl esters have been accomplished. The increase of the lipophilicity was shown to significantly improve the antioxidant activity of protocatechuic esters. Their efficiency as radical scavengers was evaluated using distinctive analytical methods, namely, 2,2-diphenyl-1-picrylhydrazyl (DPPH) UV/visible method, electrochemistry, and differential scanning calorimetry. All the new alkyl protocatechuate antioxidants studied possessed better radical-scavenging capacity than the natural antioxidant protocatechuic acid. This work has shown that the alkyl ester side chain markedly influences the lipophilicity of this type of phenolic system without disturbing the core of the molecule responsible for antioxidant activity. The data on the antioxidant activity obtained using the different analytical methods correlated well with each other and have revealed the interesting antioxidant potential of alkyl esters of protocatechuic acid.

Chain-Length Dependence of Termination Rate Coefficients in Acrylate and Methacrylate Homopolymerizations Investigated via the SP−PLP Technique

Termination rate coefficients, kt, of alkyl acrylate and alkyl methacrylate homopolymerizations at 40 °C and pressures of 1000 and 2000 bar have been measured up to high degrees of monomer conversion using the time-resolved single-pulse−pulsed-laser polymerization (SP−PLP) technique. The chain-length dependence (CLD) of kt has been deduced from SP−PLP data by adopting the power-law model, kt = i-α, where i is the chain length. For methacrylates at low degrees of monomer conversion, α is close to the theoretically predicted value of 0.16. At conversions above 20% the exponent α increases significantly with increasing conversion. This effect becomes particularly pronounced in the gel effect region, where α, e.g. for MMA, reaches values close to unity. In the case of acrylates with small alkyl ester side chain, such as methyl acrylate, α is also close to 0.16 at low conversions and increases toward higher conversions. In the case of acrylates with larger alkyl ester side chain, such as dodecyl acrylate and 2...

The effect of substrate molecular mobility on surface induced immune complement activation and blood plasma coagulation

Changing the length of the alkyl ester side chain in poly(alkyl methacrylates) provides a unique opportunity to systematically vary the mobility of the polymer chains, or in other words vary the glass transition temperature ( T g), without greatly affect the solid surface energy ( γ s) of the polymer. A series of poly(alkyl methacrylate) coatings was therefore analysed with regard to the human immune complement (IC) activation and the surface associated blood plasma coagulation cascade (CC) properties. For the IC and CC measurements we used a quartz crystal microbalance (QCM) where we modified the chemistry of the sensor surface by applying 10–30 nm thick poly(alkyl methacrylate) coatings. The surface energy was calculated from water contact angles and small differences between the coatings were observed. The surface chemistry of the coatings, as determined with X-ray photoelectron spectroscopy (XPS), showed no deviation from expected compositions. Tapping mode atomic force microscopy (TM-AFM) measurements revealed that all coatings displayed similar morphology and the roughness was in the range of 0.7–0.9 nm. Increased polymer mobility correlated with a decrease in IC activation, measured as a decreased C3c deposition at the surface. The surface induced CC, measured as fibrin clot formation at the surface, was different between the different coatings but no correlation with molecular mobility was observed. Thus, the molecular mobility of the polymer chains had a major effect on both the IC and the CC and it seems that different aspects of the chemistry of the solid surface regulate activation of the IC and the CC.

Effect of acrylate constituent units on the adhesion of polyacrylate sizes to fiber substrates

AbstractThe influences of chemical structure of (meth)acrylate monomers, including the carbon atom number of alkyl ester groups and the α‐methyl group, on the adhesion of polyacrylate sizes to all‐polyester, pure cotton, and polyester/cotton blend fiber substrates are investigated by using an impregnated roving method for warp sizing. The adhesion is evaluated in terms of the bonding strength, breaking extension, and work of break of a slightly sized roving. The polyacrylate sizes are prepared through free radical copolymerization of (meth)acrylates with acrylic acid in ethanol. It was found that the adhesion is strongly affected by the structure of acrylate monomers. The adhesion enhances with increasing the carbon atom number of alkyl ester side chains of acrylates, whether or not it is an acrylate or a methacrylate. The α‐methyl does not favor the adhesion to polyester fibers, but favor to polyester/cotton blend fibers. Moreover, the molar ratio of butyl acrylate to acrylic acid is also considered. Excessively lowering the amount of acrylate or acrylic acid damages the adhesion. A favorable molar ratio of butyl acrylate to acrylic acid is found to be about 60 : 40. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3016–3022, 2004

Evaluation of derivatives of 3-(2-oxo-1-pyrrolidine) hexahydro-1 H-azepine-2-one as dermal penetration enhancers: side chain length variation and molecular modeling

The present study examined the enhancement effect of two series of compounds derived from 3-(2-oxo-1-pyrrolidine)hexahydro-1 H-azepine-2-one. One series possessed alkyl side chains (series I) and the other alkyl ester side chains (series II). An in vitro diffusion study was performed to investigate the effect of variation in alkyl/alkyl ester side chain length of two series of compounds on the permeation of hydrocortisone (HC) across hairless mouse skin. The permeability coefficient ( P), 24 h receptor concentration ( Q 24) and skin content (SC), as well as the enhancement ratios (ER) for each parameter were recorded. A parabolic relationship was observed between the ER P, and the alkyl side chain length of the enhancers. The relationship between the length of ester side chains and ER P appeared to be relatively linear with R 2 of 0.9676. The relationship between the calculated lipophilicity (CL) and enhancement activity of the enhancers showed that for CL 5–9, series I showed higher P values compared with Azone ®, but this was not observed with series II. For CL values 4.57–7.75, a significant correlation existed between P of HC and CL of series II compounds ( R 2=0.9967). 1-Tetradecyl-3-(2-oxo-1-pyrrolidine)- ε-caprolactam showed the highest P and Q 24, with 40.5- and 18.6-fold increases over the control. In conclusion, the alkyl side chain series of compounds showed more enhancing activity than the alkyl ester side chain series.

Calorimetric study of fluorinated methacrylic and vinyl polymer blends: 1. Binary systems: determination of miscibility domains and correlation of glass transition temperatures with blends composition— application to plastic optical fibre cladding

This paper reports a calorimetric study of binary polymer blends prepared by solution mixing of fluoroalkyl methacrylic ester-methyl methacrylate (MMA) copolymers with poly(vinylidene difluoride) (PVDF) or VDF-hexafluoropropene (HFP) (or VDF-trifluoroethylene) copolymers and examines their use as materials in plastic optical fibres (POF) technology. Some interesting blends were also obtained through mechanical mixing in the molten state. As compared to the well known PVDF-poly(methyl methacrylate) (PMMA) system, miscibility domains in copolymer blends become wider when less crystalline VDF copolymers are used in place of PVDF, whereas the opposite is found for the introduction of fluorinated alkyl ester side chains in PMMA. Correlation of the observed glass transition temperatures of homogeneous phases to their compositions failed with the Fox and Gordon-Taylor relations, whereas good fits could be observed using both Kwei and Jenckel-Heutsch relations. The q and b (specific interactions) parameters in these relations are well correlated to the chemical composition, indicating the influence of strong intermolecular interactions. In fluoroalkyl methacrylic ester-containing polymers, internal interactions are competing efficiently with intermolecular ones, thus limiting the miscibility of these polymers with VDF-homo- and copolymers. Some blends of the MMA-trifluoromethyl methacrylate with VDF-HFP copolymers give good performances as POF cladding material. A more simple solution lies in the use of VDF-HFP copolymers themselves.

Order-Disorder Transition of a Hydrogel Containing an n-Alkyl Acrylate

A moderately water-swollen hydrogel with a molecularly ordered structure was prepared by copolymerizing an acrylic monomer with a hydrophobic long alkyl side group-n-stearyl acrylate (SA)-with acrylic acid (AA). The long alkyl ester side chains of the gel form lamellar layers with a thickness of ca. 5 nm, and the lamellar distance of the swollen gels is nearly 0.8 nm larger compared to that of their dry state. This indicates that water molecules in the polymer gel are preferentially adsorbed between two aggregates of stearyl groups perpendicularly aligned to the main chain. We have also found that the poly(SA-co-AA) gel undergoes a reversible order-disorder transition with change in temperature and a dramatic change in its Youngs modulus at a certain temperature

Synthesis of new conducting poly(2,5‐thienylene)s containing alkylhydroxy and alkylester side chains

AbstractThe chemical synthesis of new electroconducting poly(2,5‐thienylene)s containing alkylhydroxy and alkylester side‐chains in the β‐position of the thiophene rings is reported. The polymers were obtained by oxidative homopolymerization or copolymerization of 2‐(3‐thienyl)ethanol and 2‐(3‐thienyl)ethyl hexanoate by FeCl3 in nitromethane. Structural characterization using elemental analysis, FT‐IR and NMR spectroscopy shows that a partial nucleophilic substitution of the hydroxy group by chlorine and a partial cleavage of the ester function take place during polymerization. The presence of the ester function with a long aliphatic chain makes the polymers soluble and allows them to be processed into films. The polymers can be doped using a solution of FeCl3 to the maximum electrical conductivity of 10−3 Ω−1 cm−1.