Improvement of ethanol production in Saccharomyces cerevisiae by hetero‐expression of GAPN and FPS1 deletion

BACKGROUND: During anaerobic bioethanol fermentation of Saccharomyces cerevisiae, the main byproduct glycerol is essential to regulate redox balance (reoxidize NADH to NAD⁺), which is necessary to maintain cell growth and fermentation. Hetero‐expression of a NADP⁺‐dependent glyceraldehydes‐3‐phosphate dehydrogenase (GAPN) [EC.1.2.1.9] in S. cerevisiae could redirect the carbon flux from glycerol to ethanol involving a net oxidation of NADH. The present study investigates whether combination of GAPN hetero‐expression and glycerol exporter Fps1p disruption would result in less glycerol and more ethanol production without affecting growth rate during anaerobic fermentations. RESULTS: The results of anaerobic fermentations showed that the fps1Δ mutant with GAPN (named 4FG) produced 21.47% less glycerol and 9.18% more ethanol compared with a parental strain with a control plasmid, while the rates of growth and fermentation were not changed. Moreover, the engineered strain 4FG yielded less glycerol and acetic acid, and more ethanol than the control, fps1Δ mutant or with GAPN only. CONCLUSIONS: During anaerobic fermentations, hetero‐expression of GAPN restored the reduced grow rate of the fps1Δ mutant, and led to less byproducts and more ethanol production. This combination strategy could be used to modulate glycerol metabolism and optimize the anaerobic fermentation of S. cerevisiae. Copyright © 2011 Society of Chemical Industry     

Differential Modulation of S1PR(1–5) and Specific Activities of SphK and nSMase in Pulmonary and Cerebral Tissues of Rats Exposed to Hypobaric Hypoxia

Recent preclinical and clinical studies have unfolded the potential of pharmacological modulation of activities of sphingosine‐1‐phosphate (S1P) receptors and S1P metabolizing enzymes for the development of therapeutic interventions against a variety of pathologies. An understanding of differential and temporal effects of hypoxia exposure on the key components of S1P signalling would certainly aid in designing improved drug development strategies in this direction. In view of this, the aim of the present study was to assess the effect of progressive hypobaric hypoxia exposure on expression of S1P receptors (S1PR_1–5) and specific activities of S1P synthesizing enzymes—neutral sphingomyelinase (nSMase) and sphingosine kinase (Sphk) in pulmonary and cerebral tissues of rats exposed to simulated altitude of 21,000 feet in an animal decompression chamber. Along with this, development of cerebral and pulmonary edema and markers of inflammation were studied at 12, 24, and 48 h to validate our study model of hypobaric hypoxia‐induced stress. The protein expression of S1PR_1–5 and activities of Sphk and nSMase enzymes were observed to be dramatically affected by simulated hypobaric hypoxia exposure, concurrent with deterioration of pathology, with 12 h of exposure appearing to be the most critical of the various time points studied.     

Pharmacophore‐Based Design of Novel Oxadiazoles as Selective Sphingosine‐1‐phosphate (S1P) Receptor Agonists with in vivo Efficacy

Sphingosine‐1‐phosphate (S1P) receptor agonists have shown promise as therapeutic agents for multiple sclerosis (MS) due to their regulatory roles within the immune, central nervous system, and cardiovascular system. Here, the design and optimization of novel [1,2,4]oxadiazole derivatives as selective S1P receptor agonists are described. The structure–activity relationship exploration was carried out on the three dominant segments of the series: modification of the polar head group (P), replacement of the oxadiazole linker (L) with different five‐membered heterocycles, and the use of diverse 2,2′‐disubstituted biphenyl moieties as the hydrophobic tail (H). All three segments have a significant impact on potency, S1P receptor subtype selectivity, physicochemical properties, and in vitro absorption, distribution, metabolism, excretion and toxicity (ADMET) profile of the compounds. From these optimization studies, a selective S1P₁ agonist, N‐methyl‐N‐(4‐{5‐[2‐methyl‐2′‐(trifluoromethyl)biphenyl‐4‐yl]‐1,2,4‐oxadiazol‐3‐yl}benzyl)glycine ( 45 ), and a dual S1P_1,5 agonist, N‐methyl‐N‐(3‐{5‐[2′‐methyl‐2‐(trifluoromethyl)biphenyl‐4‐yl]‐1,2,4‐oxadiazol‐3‐yl}benzyl)glycine ( 49 ), emerged as frontrunners. These compounds distribute predominantly in lymph nodes and brain over plasma and induce long lasting decreases in lymphocyte count after oral administration. When evaluated head‐to‐head in an experimental autoimmune encephalomyelitis mouse model, together with the marketed drug fingolimod, a pan‐S1P receptor agonist, S1P_1,5 agonist 49 demonstrated comparable efficacy while S1P₁‐selective agonist 45 was less potent. Compound 49 is not a prodrug, and its improved property profile should translate into a safer treatment of relapsing forms of MS.     

Synthesis and characterization of novel two‐component conjugated polythiophenes with 3‐octyl and 3‐isooctylthiophene side chains

With copolymerization functionalization, a novel solution‐processable polymer, poly{(3‐octylthiophene)‐co‐[3‐(2‐ethyl‐1‐hexyl)thiophene]} (P3OTIOT), combining the electrochemical properties of poly(3‐octylthiophene) (P3OT) and poly[3‐(2‐ethyl‐1‐hexyl)thiophene] (P3IOT) was synthesized by the FeCl₃‐oxidative approach. The characterization of the polymers included Fourier transform infrared, ¹H‐NMR, gel permeation chromatography, thermogravimetric analysis (TGA), ultraviolet–visible spectroscopy, and photoluminescence (PL). P3OTIOT had excellent solubility in common organic solvents. Investigations of the optical properties showed that the optical band‐gap energy of P3OTIOT was similar to that of P3OT (2.43 eV) at 2.45 eV and 6% lower than that of P3IOT in CHCl₃ solutions. The bandwidth of the P3OTIOT absorption approached that of P3OT, ranging from 370 to 570 nm, and the emission maximum of P3OTIOT was only 50 nm blueshifted with respect to that of P3OT. However, the PL intensity of P3OTIOT was 7 times higher than that of P3OT. TGA studies showed that P3OTIOT had very good thermal stability, losing 5% of its weight on heating to 300°C. It is suggested that P3OTIOT has low band‐gap energy, a high PL quantum yield, and processability. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1169–1175, 2007     

The relative reactivity of 2,3‐dicarbomethoxy‐5‐norbornenes in metathesis polymerization using the original n‐chelating ruthenium carbene complex

¹H NMR spectroscopy is used to study the kinetics of metathesis copolymerization of three isomeric 2,3‐dicarbomethoxy‐5‐norbornenes using the original N‐chelating ruthenium carbene complex. Based on the experimental data the copolymerization constants of isomeric 2,3‐dicarbomethoxy‐5‐norbornenes are calculated. It is shown that the relative reactivity of endic acid dimethyl ester—(1R,2S,3R,4S)‐dimethyl bicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxylate is almost two times lower than the corresponding values for (1R,2R,3S,4S)‐dimethyl bicyclo[2.2.1]hept‐5‐ene‐2,3‐dicarboxylate, which confirms earlier findings of steric hindrance in the orientation of the monomer due to the carbene catalyst. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40130.     

Analysis of saturated free fatty acids from pollen by HPLC with fluorescence detection

A sensitive method for the determination of free fatty acids using 2‐(2‐(anthracen‐10‐yl)‐1H‐naphtho[2,3‐d]imidazol‐1‐yl) ethyl‐p‐toluenesulfonate (ANITS) as tagging reagent with fluorescence detection has been developed. ANITS could easily and quickly label fatty acids in the presence of the K₂CO₃ catalyst at 90 °C for 40 min in N,N‐dimethylformamide solvent. From the extracts of rape bee pollen samples, 20 free fatty acids were sensitively determined. Fatty acid derivatives were separated on a reversed‐phase Eclipse XDB‐C₈ column by HPLC in conjunction with gradient elution. The corresponding derivatives were identified by post‐column APCI/MS in positive‐ion detection mode. ANITS‐fatty acid derivatives gave an intense molecular ion peak at m/z [M+H]⁺; with MS/MS analysis, the collision‐induced dissociation spectra of m/z [M+H]⁺ produced the specific fragment ions at m/z [M–345]⁺ and m/z 345.0 (here, m/z 345 is the core structural moiety of the ANITS molecule). The fluorescence excitation and emission wavelengths of the derivatives were λ_ex = 250 nm and λ_em = 512 nm, respectively. Linear correlation coefficients for all fatty acid derivatives are >0.9999. Detection limits, at a signal‐to‐noise ratio of 3 : 1, are 24.76–98.79 fmol for the labeled fatty acids.     

Phospholipid Transfer Protein Deficiency Decreases the Content of S1P in HDL via the Loss of its Transfer Capability

Sphingosine‐1‐phosphate (S1P) is an amphiphilic signaling molecule, which is enriched in functional high density lipoprotein (HDL) and shows arterial protection. The distribution of S1P is changed with increased plasma phospholipid transfer protein (PLTP) activity and impaired HDL function in patients with coronary heart diseases. Therefore, we hypothesized that PLTP might transfer S1P among cells or lipoproteins. We found that plasma S1P contents were decreased by 60.1 % in PLTP knockout mice (PLTP?/?, N = 5) compared with their wild type littermates (WT, N = 5) (151.70 ± 38.59 vs. 379.32 ± 59.90 nmol/l, P<0.01). S1P content in HDL fraction (HDL‐S1P) from PLTP?/? was decreased by 64.7 % compared with WT (49.36 ± 1.49 vs. 139.76 ± 2.94 nmol/l, P<0.01). The results of the S1P transfer assay indicated that PLTP could facilitate S1P transport from erythrocytes to HDL at 37 °C in D‐Hanks buffer. Plasma content of apolipoprotein M, a specific adaptor of S1P, was not changed in PLTP?/? compared with WT. Therefore, we concluded that PLTP was a key factor to maintain plasma HDL‐S1P, and PLTP deficiency could decrease the S1P content in plasma lipoproteins, which involves its capability of transferring S1P from erythrocyte to HDL.     

Development of Colorimetric HTS Assay of Cytochrome P450 for ortho‐Specific Hydroxylation,and Engineering of CYP102D1 with Enhanced Catalytic Activity and Regioselectivity

A current challenge in high‐throughput screening (HTS) of hydroxylation reactions by P450 is a fast and sensitive assay for regioselective hydroxylation against millions of mutants. We have developed a solid‐agar plate‐based HTS assay for screening ortho‐specific hydroxylation of daidzein by sensing formaldehyde generated from the O‐dealkylation reaction. This method adopts a colorimetric dye, pararosaniline, which has previously been used as an aldehyde‐specific probe within cells. The rationale for this method lies in the fact that the hydroxylation activity at ortho‐carbon position to C? OH correlates with a linear relationship to O‐dealkylation activity on chemically introduced methoxy group at the corresponding C? OH. As a model system, a 4′,7‐dihydroxyisoflavone (daidzein) hydroxylase (CYP102D1 F96V/M246I), which catalyzes hydroxylation at ortho positions of the daidzein A/B‐ring, was examined for O‐dealklyation activity, by using permethylated daidzein as a surrogate substrate. By using the developed indirect bishydroxylation screening assay, the correlation coefficient between O‐dealkylation and bishydroxylation activity for the template enzyme was 0.72. For further application of this assay, saturation mutants at A273/G274/T277 were examined by mutant screening with a permethylated daidzein analogue substrate (A‐ring inactivated in order to find enhanced 3′‐regioselectiviy). The whole‐cell biotransformation of daidzein by final screened mutant G1 (A273H/G274E/T277G) showed fourfold increased conversion yield, with 14.3 mg L^?1 production titer and greatly increased 3′‐regioselectiviy (3′/6=11.8). These results show that there is a remarkably high correlation (both in vitro and in vivo), thus suggesting that this assay would be ideal for a primary HTS assay for P450 reactions.     

Fluorene‐based conjugated polymer with tethered thymines: click postpolymerization synthesis and optical response to mercury(II)

A kind of fluorene‐based conjugated polymer with tethered thymine (T) groups {poly[(9,9‐dioctyl)‐2,7‐fluorene‐{9,9‐dioctyl‐4–1,2,3‐triazol‐[5‐(hydroxymethyl)tetrahydrofuran‐2‐yl]‐5‐methylpyrimidine‐2,4(1H,3H)‐dione}‐2,7‐fluorene]‐co‐[(9,9‐dioctyl)‐2,7‐fluorene‐4,7‐bis(5‐thiophen‐2‐yl)benzo‐2,1,3‐thiadiazole] ( P‐3 )} was successfully synthesized by a Cu(I)‐catalyzed click reaction between the acetylene‐substituted polymer precursor {poly[(9,9‐dioctyl)‐2,7‐fluorene‐(9,9‐dioctyl‐4‐phenylacetylene fluorene)]‐co‐[(9,9‐dioctyl)‐2,7‐fluorene‐4,7‐bis(5‐thiophen‐2‐yl)benzo‐2,1,3‐thiadiazole]} and 3′‐azido‐3′‐deoxythymidine. The chemical structures of the intermediates and target polymer were verified by Fourier transform infrared spectroscopy and ¹H‐NMR analyses. The specific binding with Hg²⁺ of P‐3 was corroborated by ultraviolet–visible spectroscopy and photoluminescence analyses against other metal ions. The results show that P‐3 possessed selectivity and sensitivity toward Hg²⁺. Around 77% of photoluminescence intensity of P‐3 was quenched when the concentration of Hg²⁺ reached 7.7 × 10^?4 M and with a detection limit in the range of about 4.8 μM. A comparison experiment suggested that a synergic effect of the tethered T and S atoms interrelated with Hg²⁺ existed in P‐3 . Most of the fluorescence intensity of P‐3 was recovered upon the addition of iodide anions to the P‐3 /Hg²⁺ complex; this suggested that P‐3 could be used as a potential reversible optical Hg²⁺ probe. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

PET Radiotracers for Imaging P‐glycoprotein: The Challenge for Early Diagnosis in AD

PET radiotracer development to target in vivo P‐glycoprotein (P‐gp) could be an important strategy for the early diagnosis of neurodegenerative disorders such as Alzheimer’s disease (AD). Indeed, as a dysfunction of P‐gp is responsible for the accumulation of β‐amyloid plaques (a hallmark of AD) in brain parenchyma, P‐gp is the cause of AD onset. P‐gp substrates and inhibitors are useful for imaging the activity or expression of this protein, respectively; herein we discuss the in vivo evaluation of some ¹¹C radiotracers with P‐gp‐inhibitory activity, such as [¹¹C]MC18 and [¹¹C]MC113, as well as P‐gp substrates [¹¹C]MC266 and [¹¹C]MC80. Moreover, the radiosynthesis of all these P‐gp probes is reported.     

Identification of a Small‐Molecule Inhibitor of HIV‐1 Assembly that Targets the Phosphatidylinositol (4,5)‐bisphosphate Binding Site of the HIV‐1 Matrix Protein

The development of drug resistance remains a critical problem for current HIV‐1 antiviral therapies, creating a need for new inhibitors of HIV‐1 replication. We previously reported on a novel anti‐HIV‐1 compound, N²‐(phenoxyacetyl)‐N‐[4‐(1‐piperidinylcarbonyl)benzyl]glycinamide ( 14 ), that binds to the highly conserved phosphatidylinositol (4,5)‐bisphosphate (PI(4,5)P₂) binding pocket of the HIV‐1 matrix (MA) protein. In this study, we re‐evaluate the hits from the virtual screen used to identify compound 14 and test them directly in an HIV‐1 replication assay using primary human peripheral blood mononuclear cells. This study resulted in the identification of three new compounds with antiviral activity; 2‐(4‐{[3‐(4‐fluorophenyl)‐1,2,4‐oxadiazol‐5‐yl]methyl})‐1‐piperazinyl)‐N‐(4‐methylphenyl)acetamide ( 7 ), 3‐(2‐ethoxyphenyl)‐5‐[[4‐(4‐nitrophenyl)piperazin‐1‐yl]methyl]‐1,2,4‐oxadiazole ( 17 ), and N‐[4‐ethoxy‐3‐(1‐piperidinylsulfonyl)phenyl]‐2‐(imidazo[2,1‐b][1,3]thiazol‐6‐yl)acetamide ( 18 ), with compound 7 being the most potent of these hits. Mechanistic studies on 7 demonstrated that it directly interacts with and functions through HIV‐1 MA. In accordance with our drug target, compound 7 competes with PI(4,5)P₂ for MA binding and, as a result, diminishes the production of new virus. Mutation of residues within the PI(4,5)P₂ binding site of MA decreased the antiviral effect of compound 7 . Additionally, compound 7 displays a broadly neutralizing anti‐HIV activity, with IC₅₀ values of 7.5–15.6 μM for the group M isolates tested. Taken together, these results point towards a novel chemical probe that can be used to more closely study the biological role of MA and could, through further optimization, lead to a new class of anti‐HIV‐1 therapeutics.     

Synthesis and photovoltaic device studies of azo‐linked low‐bandgap polymers

We report the synthesis of a series of new polymers containing azo linkage as a part of the main chain. The monomer 1,2‐bis(7‐bromo‐9,9‐dioctyl‐9H ‐fluoren‐2‐yl)diazene was synthesized using a precursor approach which avoids non‐selective bromination and was copolymerized with various donor or acceptor units. The homopolymer poly[1,2‐bis(9,9‐dioctyl‐9H ‐fluoren‐2‐yl)diazene] ( P1 ) as well as the copolymers poly[1‐(9,9‐dioctyl‐9H ‐fluoren‐2‐yl)‐2‐(9,9,9′,9′‐tetraoctyl‐9H ,9′H ‐[2,2′‐bifluoren]‐7‐yl)diazene] ( P2 ), poly[1‐(9,9‐dioctyl‐7‐(4‐octylthiophen‐2‐yl)‐9H ‐fluoren‐2‐yl)‐2‐(9,9‐dioctyl‐9H ‐fluoren‐2‐yl)diazene] ( P3 ) and poly[4‐(7‐((9,9‐dioctyl‐9H ‐fluoren‐2‐yl)diazenyl)‐9,9‐dioctyl‐9H ‐fluoren‐2‐yl)benzo[c ][1,2,5]thiadiazole] ( P4 ) were synthesized by Suzuki polymerization. The copolymers poly[1‐(7‐(4,4‐dioctyl‐4H ‐cyclopenta[1,2‐b :5,4‐b ′]dithiophen‐2‐yl)‐9,9‐dioctyl‐9H ‐fluoren‐2‐yl)‐2‐(9,9‐dioctyl‐9H ‐fluoren‐2‐yl)diazene] ( P5 ) and poly[4‐(5‐(7‐((9,9‐dioctyl‐9H ‐fluoren‐2‐yl)diazenyl)‐9,9‐dioctyl‐9H ‐fluoren‐2‐yl)‐4‐octylthiophen‐2‐yl)‐7‐(4‐octylthiophen‐2‐yl)benzo[c ][1,2,5]thiadiazole] ( P6 ) were synthesized by direct arylation polymerization reaction. Polymers synthesized using the direct arylation method show good molecular weight, with absorption maxima in the range 500 to 532 nm. P5 and P6 possess low optical bandgaps of 1.81 and 1.86 eV, respectively. A power conversion efficiency of 0.53% with open circuit voltage of 0.53 V, short circuit current density of 3.1 mA cm^?2 and fill factor of 29% has been achieved with C71‐PCBM as acceptor in bulk heterojunction solar cells fabricated with P5 as donor. © 2016 Society of Chemical Industry     

Synthesis,characterization and thermal degradation of poly[2‐(3‐p‐bromophenyl‐3‐methylcyclobutyl)‐2‐hydroxyethylmethacrylate]

In this work, 2‐(3‐p‐bromophenyl‐3‐methylcyclobutyl)‐2‐hydroxyethylmethacrylate (BPHEMA) [monomer] was synthesized by the addition of methacrylic acid to 1‐epoxyethyl‐3‐bromophenyl‐3‐methyl cyclobutane. The monomer and poly(BPHEMA) were characterized by FT‐IR and [¹H] and [¹³C]NMR. Average molecular weight, glass transition temperature, solubility parameter, and density of the polymer were also determined. Thermal degradation of poly[BPHEMA] was studied by thermogravimetry (TG), FT‐IR. Programmed heating was carried out at 10 °C min⁻¹ from room temperature to 500 °C. The partially degraded polymer was examined by FT‐IR spectroscopy. The degradation products were identified by using FT‐IR, [¹H] and [¹³C]NMR and GC‐MS techniques. Depolymerization is the main reaction in thermal degradation of the polymer up to about 300 °C. Percentage of the monomer in CRF (Cold Ring Fraction) was estimated at 33% in the peak area of the GC curve. Intramolecular cyclization and cyclic anhydride type structures were observed at temperatures above 300 °C. The liquid products of the degradation, formation of anhydride ring structures and mechanism of degradation are discussed. © 1999 Society of Chemical Industry     

Synthesis and characterization of α‐butyl‐omega‐{3‐[2‐hydroxy‐3‐(N‐methyl‐N‐hydroxy‐ ethylamino)propoxy]propyl}polydimethylsiloxane

A novel synthesis path for the monotelechelic polydimethylsiloxane with a diol‐end group, α‐butyl‐omega‐{3‐[2‐hydroxy‐3‐(N‐methyl‐N‐hydroxyethylamino)propoxy]propyl}polydimethylsiloxane, is described in this article. The preparation included three steps, which were anionic ring‐opening polymerization, hydrosilylation, and epoxy addition. The structure and polydispersity index of the products were analyzed and confirmed by FTIR, ¹H NMR, ¹³C NMR, H? H, and C? H. Correlated Spectroscopy and gel permeation chromatography. The results demonstrated that each step was successfully carried out and the targeted products were accessed in all cases. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

An in vitro focus on doxorubicin hydrochloride delivery of novel pH‐responsive poly(2‐succinyloxyethylmethacrylate) and poly[(N‐4‐vinylbenzyl),N,N‐diethylamine] diblock copolymers

Novel pH‐responsive poly(2‐succinyloxyethylmethacrylate)‐b‐poly[(N‐4‐vinylbenzyl),N,N‐diethylamine] [poly(SEMA‐b‐VEA)] diblock copolymers were synthesized via reversible addition fragmentation transfer (RAFT) polymerization to investigate their self‐assembly micellar behavior. The self‐assembly behaviors of synthesized diblock copolymers with distinct molecular weights (labeled (1) to) were confirmed by ¹H NMR spectroscopy, TEM and dynamic light scattering measurements. Doxorubicin hydrochloride (DOX) loading capacity was evaluated, and the in vitro cytotoxicity effect of DOX‐loaded diblock copolymer was also studied by assessing the survival rate of the breast cancer cell line MCF‐7 with 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. The results exhibited remarkable controlled release in the MTT assay. The DOX encapsulation efficiency was calculated to be 96.4%. The size and zeta potential of DOX‐loaded poly(SEMA‐b‐VEA) diblock copolymers were 204 nm and +5.7 mV at a pH of 7.4. DOX release values after 440 h at pH 7.4, 5.4 and 4 were 22.15%, 31.43% and 47.06%, respectively. The released values of DOX‐loaded poly(SEMA‐b‐VEA) and at pH 7.4 were 22.15%, 20.5% and 17.5%, respectively. Cell survival ratios were 18.9%, 23.16% and 16.92% after 72 h. Poly(SEMA‐b‐VEA) copolymers can be considered in nanomedicine applications due to their excellent pH‐responsive micellar behavior. © 2017 Society of Chemical Industry     

Synthesis and characterization of the polyaminophenol derivatives containing thiophene in side chain: Thermal degradation,electrical conductivity,optical‐electrochemical,and fluorescent properties

Novel polyaminophenols, poly‐2‐[3‐thienylmethylene]aminophenol (P‐2,3‐TP), poly‐3‐[3‐thienylmethylene]aminophenol (P‐3,3‐TP) and poly‐4‐[3‐thienylmethylene]amino phenol (P‐4,3‐TP), were synthesized by oxidative polycondensation reaction. Metal complexes of P‐2,3‐TP were also obtained. The structures of synthesized compounds were confirmed by FT‐IR, UV‐vis, ¹H NMR, and ¹³C NMR techniques. The characterization was made by TG‐DTA, DSC, and gel permeation chromatography (GPC) analyses in addition to solubility tests. Electrical conductivities of polymers were measured by four‐point probe technique. Fluorescence measurements were carried out in various solutions and optimum concentrations and maximal intensities were determined. The new synthesized polyaminophenols are good candidates for electronic, opto‐electronic, and photovoltaic applications due to polyconjugated structures. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Functionalized Ionic Liquid-Catalyzed 1-Feruloyl-sn-glycerol Synthesis

Feruloyl Glycerol (FG) is a potential antioxidant and UV absorbing ingredient in food and cosmetic industries. Transesterifications of ethyl ferulate (EF) with glycerol to synthesize FG were performed using different functionalized ionic liquids (1‐butylsulfonic‐3‐methylimidazolium tosylate, [BSO₃HMIM]TS; 1‐propylsulfonic‐3‐methylimidazolium tosylate, [PSO₃HMIM]TS; 1‐butylsulfonic‐3‐methylimidazolium trifluoromethanesulfonate, [BSO₃HMIM]OTF; 1‐butylsulfonic‐3‐methylimidazolium hydrogen sulfate, [BSO₃HMIM]HSO₄; N‐methylimidazolium hydrogen sulfate, [HMIM]HSO₄; 1‐butyl‐3‐methylimidazolium hydroxide, [BMIM]OH; 1‐butyl‐3‐methylimidazo tetrachloride molysite, [BMIM]FeCl₄; and 1‐hexyl‐3‐methylimidazo tetrachloride molysite, [BMIM]FeCl₄) as catalysts, respectively. High EF conversion (98.0 ± 1.5 %), 1‐FG (1‐feruloyl‐sn‐glycerol) yield (88.7 ± 1.1 %) and reaction selectivity for 1‐FG (90.5 ± 2.1 %) were obtained using [BSO₃HMIM]TS as catalyst. The activation energy (E_a), the Michaelis–Menten kinetic constant (K_m), and the maximum initial reaction rate (v_max) of the transesterification are 65.9 ± 3.3 kJ/mol, 1.8 ± 0.1 mol/L, and (1.6 ± 0.4) × 10^?2 mol/(L min), respectively. Effects of catalyst loading, reaction temperature, and the molar ratio of EF to glycerol on EF conversion and reaction selectivity for 1‐FG (1‐FG yield/EF conversion) were also investigated.     

[Carboxyl‐11C]Labelling of Four High‐Affinity cPLA2α Inhibitors and Their Evaluation as Radioligands in Mice by Positron Emission Tomography

Cytosolic phospholipase A2α (cPLA2α) may play a critical role in neuropsychiatric and neurodegenerative disorders associated with oxidative stress and neuroinflammation. An effective PET radioligand for imaging cPLA2α in living brain might prove useful for biomedical research, especially on neuroinflammation. We selected four high‐affinity (IC₅₀ 2.1–12 nm ) indole‐5‐carboxylic acid‐based inhibitors of cPLA2α, namely 3‐isobutyryl‐1‐(2‐oxo‐3‐(4‐phenoxyphenoxy)propyl)‐1H‐indole‐5‐carboxylic acid ( 1 ); 3‐acetyl‐1‐(2‐oxo‐3‐(4‐(4‐(trifluoromethyl)phenoxy)phenoxy)propyl)‐1H‐indole‐5‐carboxylic acid ( 2 ); 3‐(3‐methyl‐1,2,4‐oxadiazol‐5‐yl)‐1‐(2‐oxo‐3‐(4‐phenoxyphenoxy)propyl)‐1H‐indole‐5‐carboxylic acid ( 3 ); and 3‐(3‐methyl‐1,2,4‐oxadiazol‐5‐yl)‐1‐(3‐(4‐octylphenoxy)‐2‐oxopropyl)‐1H‐indole‐5‐carboxylic acid ( 4 ), for labelling in carboxyl position with carbon‐11 (t_1/2=20.4 min) to provide candidate PET radioligands for imaging brain cPLA2α. Compounds [¹¹C] 1 – 4 were obtained for intravenous injection in adequate overall yields (1.1–5.5 %) from cyclotron‐produced [¹¹C]carbon dioxide and with moderate molar activities (70–141 GBq μmol^?1) through the use of Pd⁰‐mediated [¹¹C]carbon monoxide insertion on iodo precursors. Measured logD_7.4 values were within a narrow moderate range (1.9–2.4). After intravenous injection of [¹¹C] 1 – 4 in mice, radioactivity uptakes in brain peaked at low values (≤0.8 SUV) and decreased by about 90 % over 15 min. Pretreatments of the mice with high doses of the corresponding non‐radioactive ligands did not alter brain time–activity curves. Brain uptakes of radioactivity after administration of [¹¹C] 1 to wild‐type and P‐gp/BCRP dual knock‐out mice were similar (peak 0.4 vs. 0.5 SUV), indicating that [¹¹C] 1 and others in this structural class, are not substrates for efflux transporters.     

Blue fluorescent conductive poly(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene) homopolymer and its highly soluble copolymers with styrene or 9‐vinylcarbazole

A new blue fluorescent monomer, 9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene, was designed and synthesized in good yield. Its homopolymer poly(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene) (P(ADN)) and soluble conductive vinyl copolymers poly[(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene)‐co‐styrene] (P(ADN‐co‐S)) and poly[(9,10‐di(1‐naphthalenyl)‐2‐vinylanthracene)‐co‐(9‐vinylcarbazole)] (P(ADN‐co‐VK)) were synthesized using free radical solution polymerization. All the polymers showed high glass transition mid‐point temperatures (203 to 237 °C) and good thermal stabilities. The photoluminescence emission of the copolymers was similar to that of P(ADN) (with two maxima at 423 and 442 nm). The lifetimes of P(ADN‐co‐S) (6.82 to 7.91 ns) were all slightly less than that of P(ADN) (8.40 ns). The lifetime of P(ADN‐co‐VK) increased from 7.8 to 8.8 ns with an increase in VK content. The fluorescence quantum yields of P(ADN‐co‐S) showed an overall increasing tendency from 0.42 to 0.58. The quantum efficiencies of P(ADN‐co‐VK) decreased from 0.36 to 0.19 with an increase of VK fraction. With increasing S/VK content, the highest occupied molecular orbital of P(ADN‐co‐S)/P(ADN‐co‐VK) ranged from ?5.58 to ?5.73 eV, which was similar to that of P(ADN) (?5.71 eV). The band gaps of P(ADN‐co‐S) and P(ADN‐co‐VK) were about 2.97 eV, which were equal to that of P(ADN), and smaller than that of 2‐methyl‐9,10‐di(1‐naphthalenyl)anthracene (MADN) (3.04 eV) and poly(9‐vinylcarbazole) (3.54 eV). Preliminary electroluminescence results were obtained for a homojunction device with the configuration ITO/MoO₃ (20 nm)/P(ADN)/LiF (1 nm)/Al (100 nm), which achieved only 30–50 cd m^?2, due to P(ADN) having a low mobility of 4.7 × 10^?8 cm² V^?1 s^?1 compared to that of its model compound MADN of 6.5 × 10^?4 cm² V^?1 s^?1. © 2013 Society of Chemical Industry     

Synthesis and characterization of block comb‐like copolymers P(A‐MPEO)‐block‐PSt

Amphiphilic block comb‐shaped copolymers, poly[poly(ethylene oxide) methyl ether acrylate]‐block‐polystyrene [P(A‐MPEO)‐block‐PSt] with PSt as a handle, were successfully synthesized via a macromonomer technique. The reaction of MPEO with acryloyl chloride yielded a macromonomer, A‐MPEO. The macroinitiator PSt capped with the dithiobenzoate group (PSt‐SC(S)Ph) was prepared by reversible addition–fragmentation transfer (RAFT) polymerization of styrene in the presence of benzyl dithiobenzoate, and used as macroinitiator in the controlled radical block copolymerization of A‐MPEO at room temperature under ⁶⁰Co irradiation. After the unreacted macromonomer A‐MPEO had been removed by washing with hot saturated saline water, block comb‐shaped copolymers were obtained. Their structure was characterized by ¹H NMR spectroscopy and gel permeation chromatography. The phase transition and self‐assembling behaviour were investigated by atomic force microscope and differential scanning calorimetry. Copyright © 2004 Society of Chemical Industry