Cinnamoyl Groups Research Articles

New photosensitive semi aramid/organoclay nanocomposite containing cinnamoyl groups: Synthesis and characterization

New poly(ether–amide)/layered silicate nanocomposites (PEAN) containing dibenzalacetone and cinnamoyl moieties were prepared via solution intercalation technique from poly(ether–amide) 6 and organo-MMT in a solution of N,N-dimethylacetamide (DMAc). New dicarboxylic acid 4 was synthesis from two step reactions. At first 4,4′-bis(1,4-diphenoxybutane) dialdehyde 3 was synthesized from 1,4-dibromobutane and 4-hydroxybenzaldehyde, then solvent free reaction using to synthesis 4,4′-bis(1,4-diphenoxybutane) diacrylic acid from dialdehyde 3 and malonic acid. Poly(ether–amide) (PEA) chains were synthesized from 4,4′-bis(1,4-diphenoxybutane)diacrylic acid 4 and 2,5-bis(4-aminobenzylidene)cyclopentanone 5 via a direct polycondensation reaction. The synthesized PEA was characterized by Fourier transform infrared spectra (FTIR), nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC) and UV–Vis spectroscopy. The distribution of organoclay and nanostructure of the nanocomposites were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses. The thermal properties and flammability of the nanocomposites were investigated by thermogravimetric analysis (TGA), differential scanning calorimetric (DSC) and microscale combustion calorimeter (MCC). In the presence of organoclay shows a good effect on improving the flame retardancy of the PEA, reflecting the decrease in heat release rate (HRR) and the total heat release (THR) of the nanocomposites, while the thermal stability of nanocomposites only changed slightly compared to the neat polymer. With the increase of the loading of organoclay, the nanocomposites showed improved flame retardancy and higher char residues.

(E)-1-[2-Hydroxy-4,6-bis(methoxymethoxy)phenyl]-3-phenylprop-2-en-1-one

The title compound, C19H20O6, consists of a tetra­substituted benzene ring with one substituent being an α,β-unsaturated cinnamoyl group, which forms an extended conjugated system in the mol­ecule. In addition, two meth­oxy­meth­oxy and one hy­droxy group are bonded to the central benzene ring. The dihedral angle between eh rings is 10.22 (10)°. An intra­molecular hydrogen bond is observed between the hy­droxy group and the carbonyl O atom. One of the meth­oxy­meth­oxy substituents is conformationally disordered over two sets of sites with site-occupation factors of 0.831 (3) and 0.169 (3).

Synthesis and Properties of Degradable Copolymers Composed of Poly(ε‐caprolactone) and 3,4‐Dihydroxycinnamic Acid

AbstractPhotoreactive and degradable hyperbranched (HB) copolymers with various 3,4‐dihydroxycinnamic acid (DHCA) compositions, poly(ε‐caprolactone)‐co‐poly(3,4‐dihydroxycinnamic acid) (PCL‐co‐PDHCA), were obtained by thermal melt‐polycondensation of PCL and DHCA. The HB structures and the branching degree (BD) of the PCL‐co‐PDHCA copolymers were confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR). The melting points (Tm) of the PCL‐co‐PDHCA copolymers changed depending on the PCL and DHCA composition by differential scanning calorimetry (DSC) measurements. Wide angle X‐ray diffraction (WXRD) analysis showed semi‐crystalline of the PCL and PCL‐co‐PDHCA polymers. The PCL‐co‐PDHCA copolymers showed good photoreactivities and fluorescent properties. Crosslinking of the cinnamoyl groups in the copolymers caused by UV irradiation affected the thermal stability and wettability slightly. Moreover, the hydrolysis experiments revealed that copolymers are facile degradable.

Syntheses and structure–activity relationship studies of N-substituted-β-d-glucosaminides as selective cytotoxic agents

Twenty-four diosgenyl saponins bearing cinnamoyl, carbamido and thiosemicarbazone groups were synthesized concisely. The cytotoxicities of the synthetic compounds on six human caner cell lines were evaluated employing MTT method. Structure–activity relationship could be observed, and two of the synthesized compounds (5c and 5f) exhibited selective inhibition on HeLa and MCF-7 cells, while three of them (5d, 5f and 5h) showed strong inhibition against HT1080.

Preparation and characterization of UV-sensitive chitosan for UV-cure with poly(ethylene glycol) dimethacrylate

In this study, gel membranes of chitosan-g-poly(ethylene glycol) dimethacrylate (CS-g-PEGDMA) with pH sensitive properties were synthesized without employing any photo-initiator and crosslinker. First, CS was endowed with UV-sensitive property by reaction with cinnamoyl chloride in methanesulfonic acid. The reaction mainly occurred on the hydroxyl groups of the pyranose unit, while most C-2 amino groups were protected. The substitution degree of cinnamoyl group was 0.98, while the protection efficiency of –NH2 was about 80 %. Upon UV-irradiation, initial free radicals were produced only along the cinnamoyl-modified CS chains, which induced the grafting of PEGDMA from the chitosan chains and eventually the crosslinking. Increasing the feeding amount of PEGDMA increased the grafting ratio as well as the crosslinking density. The Tg value decreased from 161 °C for the pure chitosan to about 90 °C for the CS-g-PEGDMA with a grafting ratio of 1.29. Two stages of degradation correspondent to the individual degradation of CS chains and the PEGDMA chains were observed for all CS-g-PEGDMA copolymers, demonstrating their nature of graft copolymers. The tensile mechanical properties of the CS-g-PEGDMA membranes were affected by the two opposing factors: inter-connected soft PEGDMA chains and crosslinking density; and the optimum properties were achieved when the grafting ratio was increased to about 0.80. By combining CS and PEGDMA components, these copolymer membranes thus have the potential to be used as biomedical membranes.

Photoalignment of liquid crystals by a covalently attached self-assembled ultrathin film

In this paper, the polyanion-containing cinnamoyl group (PACSS-CF3) was self-assembled with diazoresin (DR) to form a kind of stable covalent ultrathin film by irradiation with 365 nm UV light. The photoalignment properties of the DR/PACSS-CF3 covalent film were investigated. The covalent film was found to have anisotropy after irradiation by 297 nm linearly polarised ultraviolet light (LPUVL), and could induce uniform alignment of liquid crystals (LCs). The pretilt angle of the LC was 2.5°. The stability of the film was enhanced by the covalent bonds. The films were thermally stable to 180°C. Polarised UV-Vis spectroscopy was utilised to investigate the photochemical process of the covalent film. It was found that cinnamoyl moieties parallel to the polarisation direction of the LPUVL were consumed by the photoreaction faster than those perpendicular to the polarisation direction. It can be concluded that the selective photoreaction induced the anisotropy of the films. The anisotropic films induced the homogeneous alignment of LC.

Studies on photoreactive and biodegradable copolymers composed of poly(ɛ-caprolactone) and 4-hydroxycinnamic acid

A novel group of photoreactive and biodegradable copolymers known as poly(ɛ-caprolactone)-co-poly(4-hydroxycinnamic acid) (PCL-co-P4HCA) was obtained by the thermal melt polycondensation of poly(ɛ-caprolactone) (PCL) with 4-hydroxycinnamic acid. The chemical structures of the PCL-co-P4HCA copolymers were analyzed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The melting points of the PCL-co-P4HCA copolymers were dependent on the PCL and 4HCA compositions, as observed by differential scanning calorimetry measurements. Wide-angle X-ray diffraction (WXRD) analysis showed highly crystalline structures of the P4HCA, PCL and PCL-co-P4HCA polymers. The PCL-co-P4HCA copolymers were fluorescent and had good photoreactivities. Crosslinking of the cinnamoyl groups in the copolymers via ultraviolet (UV) irradiation significantly affected the fluorescence, thermal stability, hydrophobicity and water absorption of the resultant copolymers. The PCL-co-P4HCA copolymers underwent degradation when placed in buffer solutions at pH 7.4 and pH 13.3, and UV irradiation was able to regulate the degradation process. The photoreactive and biodegradable copolymers with high thermal stability may be potentially applied in both the biomedical and environmental fields. Fluorescence emission spectra of PCL-co-P4HCA50 with UV irradiation at λ=302 nm for various times, and the inset shows the fluorescent intensity changes with UV irradiation time.

Regioselectivity control of photodimerization of liquid-crystalline cinnamoyl compounds by phase variation: dual functionality of p-terphenyl substituent as a mesogen and a triplet sensitizer

Cinnamoyl-functionalized liquid-crystalline (LC) compounds having a 4″-substituted [1,1′;4′,1″]terphenyl (p-terphenyl) as mesogens were synthesized to investigate the abilities of the mesogen to act as a triplet sensitizer. UV (365nm) irradiation of the LC compound having 4″-cyano-p-terphenyl in the crystalline and LC phases regioselectively produced the photodimers with a head-to-tail and a head-to-head cyclobutane unit, respectively. The p-terphenyl thus played the role of triplet sensitizer because the cinnamoyl group does not absorb 365nm light. Due to the dual functionality of the p-terphenyl as the mesogen and the triplet sensitizer, we successfully performed the photochemical and regioselective cycloaddition to obtain two different LC dimers from one LC monomer.

Single Photon Emission Computed Tomography Imaging Agents for Formyl Peptide Receptors 1 and 2

Formyl Peptide Receptors (FPR) 1 and 2 are key in the signalling pathway of inflammation, and are found on leucocytes in particular neutrophils. Inflammation is a major marker of many disease states in particular Ischaemia-reperfusion injury and atherosclerosis.1 Identifying cells with high expression of FPR1 and FPR2 is important in the diagnosis and therapy of these diseases. Single Photon Emission Computed Tomography (SPECT) is an incredibly sensitive imaging modality and ideal for imaging receptors on the surface of cells as they are only present in extremely low concentrations. Two peptides have been identified as targets for FPR1 and FPR2, cFLFLFK2 and WKYMVm3 respectively. cFLFLFK is a hexapeptide with cinnamoyl group at the c-terminus, which acts as an antagonist for FPR1. WKYMVm has been shown to have agonistic effect on FPR2. These two peptides have been modified with 99mTc chelates to give SPECT imaging agents for FPR1 and FPR2. The biological properties of the agents have been investigated so that they maintain specific binding to the FPR. The results obtain demonstrate that the FPRs (in particular FPR1 and FPR2) provide potential targets for visualising inflammation in disease. The research has been supported by the BBSRC and GE Healthcare.

Synthesis of novel photochromic spiropyran dyes containing quaternary ammonium salt or cinnamoyl moiety and their properties as photoinitiators

AbstractThree novel spiropyran (SP) dyes containing quaternary ammonium salt or cinnamoyl moiety were synthesized and their photosensitive properties as photoinitiator were characterized by UV–vis spectroscopy. The intramolecular electron transfer of SP dyes containing quaternary ammonium salt was much faster and can initiate the photopolymerization under UV irradiation though the photochromic properties than those of SPs containing cinnamoyl group. A photoinitiation system containing SPs and the hexaarylbisimidazoles was studies, and the initiation properties were tested by monitoring the conversion rate of double‐bond at 810 and 1640 cm−1 with ‐time infrared spectroscopy. It was found that the system containing our SP derivatives exhibited much higher initiating efficiency than ever reported SP dyes in the photopolymerization of 2‐phenoxyethylacrylate/N‐vinylcarbazole. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Photoinduced mendable network polymer from poly(butylene adipate) end-functionalized with cinnamoyl groups

A network polymer with photoinduced mending abilities was prepared from cinnamoyl-telechelic prepolymer of poly(butylene adipate), PBAC2, and a tetra-cinnamoyl linker, C4, by photodimerization. The photodimerization reaction of the cinnamoyl groups was analyzed using both ultraviolet (UV)/visible (vis) and infrared (IR) spectroscopy. In the reaction, the isomerization of the cinnamate group from the trans to the cis conformation competes with the dimerization reaction of cinnamates. The fractions of dimer and isomer populations estimated from the UV/vis spectra revealed that dimerization was the more preferred reaction at temperatures higher than the melting point of PBAC2. When a film of the network polymer was damaged by tapping, the cinnamate dimers dissociated to form cinnamate monomers due to the reversibility of the dimerization. To recover the network structure, these monomers could be dimerized once again through a photoirradiation process. These results show that cracks in the network polymer can be recovered through photoirradiation.

Interfacial Assembly of a Series of Cinnamoyl-Containing Bolaamphiphiles: Spacer-Controlled Packing, Photochemistry, and Odd–Even Effect

A series of bolaamphiphiles with 4-hydroxycinnamoyl head groups and different length of the alkyl spacers (n = 6-12) were designed to investigate their photochemistry in the organized films obtained from the air/water interface. It has been found that both the length and odd-even number of the spacers can finely tune the molecular packing as well as the photochemistry. When the spacer length was changed from 6 to 12 methylene units, the assemblies changed from J aggregate to H aggregate. The molecules with even-numbered polymethylene spacer tend to form three-dimensional nanorod structure at the air/water interface. For the assembly of derivatives with odd-numbered spacers, diverse morphologies such as nanospirals and nanofibers were observed depending on the chain length and the surface pressures. The different packing of bolaamphiphiles could subsequently affect the photochemistry of the cinnamoyl groups in the organized films. The spacer effect in the assembly can be understood from the cooperation between H-bond of the phenolic hydroxyl and the amide groups, π-π stacking as well as the hydrophobic interactions of the alkyl spacer. A packing model was proposed to explain the phenomenon.

Photo alignment Behaviors of Photopolymer with Cinnamate Group by LPUV Method

The side chain photopolymer containing terminally substituted methoxy cinnamoyl ester was synthesized and characterized. The para position in the methoxy cinnamoyl group was connected with polymer backbone through 4 numbers of methylene spacer. A good thermal stability of photopolymer was measured by thermogravimatric analysis (TGA) measurement until 400 ℃ while the glass transition temperature was observed that high PMC according to the results of differential scanning calorimetry (DSC). The nematic liquid crystal (NLC) pretilt angle generated was about 0.06-1.66 by polarized different UV exposure energy. Especially, the low pretilt angle of the NLC was measured by the longer polarized UV exposure time. This result indicated that the NLC pretilt angle generated sensitively depends on the UV exposure time on the photopolymer layer.

Synthesis, spectral characterization and crystal structural of 1-(2-Morpholinoethyl)-3-(3-phenylacryloyl)thiourea

Novel cinnamoyl thiourea derivative of 2-morpholino ethylamine, namely 1-(2-Morpholinoethyl)-3-(3-phenylacryloyl)thiourea have been successfully synthesized. The reaction of cinnamoylisothiocyanate with 2-morpholino ethylamine gave the compounds (I). The new compound was analyzed and characterized by typical spectroscopic techniques, namely IR and 1H and 13C multi-nuclear magnetic resonance (NMR). The structure of I was determined by single crystal X-ray diffraction method and crystallised in the triclinic system with space group PA«, a = 6.1452(14)A, b = 9.731(2)A, c = 14.690(3)A, α = 98.711(4)°, β = 93.971(4)°, γ = 104.444(4)° and Z = 2. The molecule adopts cis-trans configuration with respect to the position of the 2-morpholino ethylamine moiety and cinnamoyl groups against the S atom across the C-N bonds. The infrared spectra of I showed four significant stretching vibrations of v(N-H), v(C=O), v(C-N) and v(C=S) at 3167, 1675, 1330 and 845 cm-1, respectively. The 13C NMR chemical shift for the thiourea moiety appeared at ca. dC 179 ppm. Key words: Thiourea, spectroscopy, x-ray crystallography.

Effects of ethylene as comonomer on the active center distribution of 1-hexene polymerization with MgCl 2-supported Ziegler–Natta catalysts

1-Hexene homopolymerization and 1-hexene–ethylene copolymerization with TiCl 4/MgCl 2–Al(C 2H 5) 3 catalyst were compared to investigate the effect of ethylene on the distribution of active centers. The polymerizations were quenched with cinnamoyl chloride, and the number of active centers ([C*]/[Ti]) was determined by measuring the cinnamoyl group labeled on the propagation chains. Both polymer samples were fractionated into 9–10 fractions according to molecular weight, and [C*]/[Ti] in each fraction was also determined. Adding small amount of ethylene in 1-hexene polymerization markedly increased the number of active centers that produce low molecular weight polymer. This phenomenon agrees with the mechanism suggesting the presence of Ti−CH(CH 3)(CH 2) 3CH 3 type dormant sites and their activation by ethylene. The k p value of the newly emerging active centers in the copolymerization system is much lower than that of the homopolymerization system. In the copolymerization system, the active centers producing polymer chains of the second highest molecular weight and isotacticity show the highest k p value, while those producing polymer of the highest molecular weight and isotacticity show only the second highest k p. On the other hand, the active centers producing polymer with lower–middle chain length show the lowest ethylene incorporation rate. These results disclose differences of catalytic properties between the multiple active center types and correlations between their different kinetic parameters, which may lead to new understanding of the active centers and polymerization mechanism.

(E)-2-(3-Cinnamoylthioureido)acetic acid dimethyl sulfoxide disolvate

In the title compound, C12H12N2O3S·2C2H6OS, the acetic acid and cinnamoyl groups adopt Z and E configurations, respectively, with respect to the thio group about the C—N bonds. The components of the asymmetric unit are connected by N—H⋯O and O—H⋯O hydrogen bonds and in the crystal weak inter­molecular C—H⋯O and C—H⋯S hydrogen bonds further connect the components into chains along the b axis. In the main mol­ecule, an intra­molecular N—H⋯O hydrogen bond is also present.

Three New Steroidal Glycosides from the Roots of Cynanchum auriculatum

AbstractThree new C21 steroidal glycosides with a cinnamoyl group at C(12) and a 2‐methylbutanoyl group at C(20), and a straight sugar chain at C(3), namely cyanoauriculosides C–E (1–3, resp.), together with three known steroidal derivatives, were isolated from the roots of Cynanchum auriculatum (Asclepiadaceae). Their structures were determined by spectroscopic analyses and chemical methods. The known constituents were identified as wilfoside K1N (4), cynanauriculoside II (5), and auriculoside IV (6).

Photochemical Construction of Coumarin Fluorophore on Affinity-Anchored Protein

A simple and unique construction of a coumarin fluorophore on a prey protein has been achieved by sequential photoreactions using a nonfluorescent bait protein. The bait protein was first modified with a novel diazirine-based photo-cross-linker containing an o-hydroxycinnamoyl unit. The strategy involves two wavelength-dependent photoreactions: photolysis of the diazirine group and E to Z photoisomerization of the cinnamoyl group. The cross-linked interacting partners were cleaved by the consecutive steps of photoisomerization and thermal lactonization accompanied with the creation of a coumarin derivative on the prey protein as a fluorescent tag. Finally, the methodology was successfully applied for coumarin labeling of antilysozymes expressed on living B cells by using photoactivatable lysozymes.

Exceptionally small supramolecular hydrogelators based on aromatic–aromatic interactions

We report herein the use of an aromatic–aromatic interaction to produce small molecule hydrogelators that self-assemble in water and form molecular nanofibers in the resulting hydrogels. Among these hydrogelators, a hydrogelator (6) made from a phenylalanine and a cinnamoyl group represents the lowest molecular weight (MW = 295.33 g/mol) peptide-based hydrogelator prepared to date. The supramolecular hydrogels were characterized by transmission electron micrograph (TEM) and fluorescence spectroscopy, and the results obtained by both techniques correlate well with their rheological properties. Notably, compound 6 can undergo cis/trans-isomerization upon UV irradiation.

Preparation and Characterization of a pH-Responsive Core Cross-linked Polymer Micelle

Poly(ethylene glycol)-b-poly(2-(diethylamino) ethyl methacrylate-co-2-cinnamoyl-oxyethyl acrylate) (PEG-b-P(DEA/CEA)) was prepared by reversible addition-fragmentation chain transfer (RAFT) controlled radical polymerization. pH-responsive association behaviour of PEG-b-P(DEA/CEA) in 0.1 M NaCl was characterized by dynamic light scattering (DLS). As solution pH is increased from an acidic pH, the hydrodynamic radius (Rh) increases, indicative of the polymer micelle formation. The formation of a micelle was also supported by static light scattering (SLS) data. The cinnamoyl groups in the core of the polymer micelle undergo photodimerization, yielding cross-links between polymer chains. The core of the polymer micelle was fixed, which was confirmed by DLS, SLS, and small angle X-ray scattering (SAXS) techniques. When pH is decreased to 3, Rh of the core cross-linked (CCL) polymer micelle slightly increases due to the protonation of the DEA unit in the cross-linked core. The reversible pH-induced swelling and shrinking behaviour can be observed.