Cinnamate Moiety Research Articles

Novel surface fixation technology of hydrogel based on photochemical method: Heparin‐immobilized hydrogelated surface

AbstractThis article reports a novel photoinduced surface process technology enabling simultaneous hydrogel formation and its surface fixation on polymeric substrates. The process consists of layering two different types of photoreactive coatings on a polymeric surface, an azidophenyl‐bearing polymer as an adhesive layer and cinnamoylated copolymer as a hydrogel layer, and subsequent UV irradiation. The photoreactive adhesive polymer coated on a substrate is poly(m‐azidostyrene), in which photoreaction of phenyl azido groups is responsible for the chemical bonding between the substrate and hydrogel. N,N‐dimethylacrylamide copolymer containing cinnamate moieties in their side chains, which undergo photocrosslinking via intermolecular dimerization, was applied as an overcoat on the adhesive layer. UV irradiation resulted in the formation of hydrogel chemically bonded onto the substrate. This was confirmed by ESCA measurements. A heparin‐immobilized hydrogelated surface with controlled release characteristics was demonstrated. © 1993 John Wiley & Sons, Inc.

Preparation and characteristics of photocrosslinkable hydrophilic polymer having cinnamate moiety

AbstractThe reaction of copolymer of N,N‐dimethylacrylamide (DMAA) and bromoethyl methacrylate with potassium cinnamate produced water‐soluble photosensitive polymers. Photosensitive polyDMAA films were irradiated with a 400 W high‐pressure mercury lamp (λ > 280 nm) to produce crosslinked polymers, which were swollen in water. The degree of swelling was controlled by the irradiation time and content of cinnamate moieties in copolymers. Higher cinnamoylation and longer irradiation time resulted in higher yield of crosslinked polymers and less swellability. Partial degelation upon irradiation at λ ∼ 254 nm was observed. The advantage of gelation via photodimerization over conventional chemical crosslinking methods is discussed in conjunction with biomedical applications. © 1992 John Wiley & Sons, Inc.

The synthesis of siloxane‐based polymers containing photoactive cinnamate moieties

AbstractThree ways of synthesizing cinnamate‐based siloxane polymers suitable for photoisomerization purposes have been employed. The route involving direct hydrosilation of the photoactive unit and a non‐photoactive alkene with the homopolymer poly(methylsiloxane) has the severe disadvantages that the polymer is coloured, crosslinking during work‐up or storage commonly occurs and also some of the cinnamate CC double bonds are reduced during the hydrosilation. This loss of the chromophore can be decreased but not eliminated by its hydrosilation with the copolymer poly(dimethylsiloxane‐co‐methylsiloxane). All of the available SiH sites are now reacted with the cinnamate ester but a low concentration of active units on the polymer is still maintained. The most successful method of preventing loss of the chromophore is best achieved by functionalising the polymer via hydrosilation with allyl acetate, followed by hydrolysis of the acetate to the alcohol and finally esterification with the acid chloride of the chromophore. This procedure in contrast to the other methods, yields the photoactive polymer as an almost colourless, mobile liquid which is stable on storage and in which no reduction of the chromophore has occurred.

Photoreactivity and emission properties of liquid-crystalline twin dimers containing cinnamic acid moieties at both ends of ethylene glycol spacers. I. Synthesis, thermotropic properties and photoreactivity

Abstract Twin dimers containing 4-methoxycinnamic acid moieties at both ends of various lengths of ethylene glycol spacers (nEGMC) were found to exhibit liquid-crystalline phase behaviour, while those with cinnamic acid moieties (nEGC) at both ends did not show the liquid-crystalline phase behaviour. The liquid-crystalline phase behaviour of nEGMC depended on the length of the ethylene glycol spacers, n. Photoirradiation of nEGMC at >300nm resulted in the formation of photodimers through cyclobutane ring formation at the C=C part of the 4-methoxycinnamic acid moieties. The photoreaction was explored by following a decrease in vC=C (FTIR), formation of the photodimers (GPC) and structural analysis of the photoproducts (NMR). It was found that the morphology of the systems strongly affected the photoreactivity and the head-to-head photodimer was predominantly formed. The photoreactivity of nEGMC is discussed in relation to the morphology of the systems.

Photoreactivity and emission properties of liquid-crystalline twin dimers containing cinnamic acid moieties at both ends of ethylene glycol spacers. II. Emission properties

Abstract Emission properties of liquid-crystalline twin dimers containing 4-methoxy-cinnamic acid moieties at both ends of various ethylene glycol derivatives (nEGMC), where n denotes the number of the ethylene glycol units in the spacers, have been explored by steady-state and time resolved fluorescence spectroscopy in relation to the morphology of the system. Characteristic emissions were observed in the twin dimers, particularly in 2EGMC and 5EGMC, which were ascribed to excimer emission, and the energy gap between the locally excited state (monomer emission) and the excimer state and could be correlated to the difference in the spatial orientation of the mesogenic 4-methoxycinnamate groups adopted in nEGMC in the ground state. The picosecond time resolved fluorescence spectroscopy revealed no observed rise in the excimer emission in any sample at any temperature, indicating that the excimer is most probably formed by direct excitation of the pair wise arrangement of the 4-methoxycinnamate moieties in ...

Photochromic systems. Part 1. Structural and spectroscopic study of photochromically active products of Stobbe condensation. 2,3-Dibenzylidenesuccinic acid and its anhydride

E,E-2,3-Dibenzylidenesuccinic acid (2) and its anhydride (1) were synthesized, their crystal structures and 1H and 13C nuclear magnetic resonance spectra were determined, and electron charge densities of carbon atoms were calculated. These results were related to the corresponding data available for E-cinnamic acid (3) in order to evaluate the effect of structural changes in a series 3 → 2 → 1 on the molecular parameters and spectroscopic properties of the cinnamic system. In the molecule of 2 most of the steric strain is released by the rotation about the C(α)—C(α′) bond giving rise to a structure consisting of two, approximately independent, cinnamic acid moieties. In 1, severe steric strain is introduced, as demonstrated by the unusually large values of the CCC bond angles exocyclic with respect to the anhydride ring, as well as by significant deviations from the plane of the cinnamic skeleton. The geometry of 1 results in an intramolecular shielding of the aromatic hydrogen atoms due to the proximity of the two benzene rings; this shielding effect for the ortho, meta, and para hydrogen atoms correlates well with the intramolecular distances between the corresponding positions of both rings. The common linear relationship between 13C chemical shifts and the electron charge densities on the given carbon atom has been obtained for compounds 1, 2, and 3.Crystal data. Anhydride (1): space group P21/c with a = 13.536(3), b = 14.391(3), c = 7.159(1) Å; β = 98.69(1)°; Rw = 0.029 and R = 0.055. Succinic acid (2): space group [Formula: see text] with a = 8.881(3), b = 9.786(1), c = 11.355(3) Å; α = 85.56(1), β = 88.76(2), γ = 69.46(2)°; Rw = 0.048 and R = 0.081. This compound cocrystallizes with one molecule of the solvent (acetic acid). Keywords: photochromic, cinnamic, succinic.

Lymphatic absorption of hypolipidemic compound, 1-O-[p-(myristyloxy)-alpha-methylcinnamoyl] glycerol (LK-903).

The intestinal absorption process of 1-O-[p-(myristyloxy)-alpha-methylcinnamoyl] glycerol (LK-903), a new hypolipidemic compound, was studied in rats. When 3H-LK-903 or 3H-LKA [3H-p- (myristyloxy)-alpha-methyl cinnamic acid], labeled at the cinnamic acid moiety, or 14C-LK-903, labeled at the glycerol moiety, were administered orally to thoracic duct-cannulated rats at a dose of 0.233 mmol/kg, 31.1, 6.7 and 18.1% of the dose, respectively, appeared in the lymph within 24 h. In this case, radioactive compounds in the lymph lipids consisted of LKA (radioactivity was not detected in the fraction of LKA with 14C-LK-903), LK-903, diglyceride analogues and triglyceride analogues. The percentages of the triglyceride analogues were the highest, followed by the diglyceride analogues. On the other hand, when doubly labeled LK-903 (3H/14C = 1, corrected ratio) was administered orally, the values of 3H/14C for the monoglyceride, diglyceride and triglyceride analogues in the lymph were 1.2-1.5, 1.7-1.9 and 1.9-2.7, respectively. The lymphatic absorption of LK-903 was stimulated by the presence of lecithin but inhibited by a high dose of triolein. The results indicated that (1) LK-903 formed micelles in the intestine, (2) a large part of LK-903 was absorbed as such, (3) a part of LK-903 was hydrolyzed in the intestinal mucosa, and (4) a part of LKA formed by hydrolysis was again utilized to synthesize the higher glycerides and absorbed via the lymphatic absorption route for lipids.

Photodimerization and photopolymerization of amphiphilic cinnamic acid derivatives in oriented monolayers, vesicles and solution

AbstractCinnamic acid moieties were incorporated into amphiphilic compounds containing one and two alkyl chains. These lipid‐like compounds with photoreactive units undergo self‐organization to form monolayers at the gas‐water interface and bilayer structures (vesicles) in aqueous solutions. The photoreaction of the cinnamic acid moiety induced by 254 nm UV light was investigated in the crystalline state, in monolayers, in vesicles and in solution in organic solvents. The single‐chain amphiphiles undergo dimerization to yield photoproducts with twice the molecular weight of the corresponding monomers in organized systems. The photoreaction of amphiphiles containing two cinnamic acid groups occurs via two mechanisms: The intramolecular dimerization produces bicycles, with retention of the molecular weight of the corresponding monomer. The intermolecular reaction leads to oligomeric and polymeric photoproducts. In contrast to the single‐chain amphiphiles, photodimerization processes of lipoids containing two cinnamic acid moieties also occur in solution in organic solvents.

Study of photopolymers, 25. Photochemical reaction of dilute solutions of polymers containing pendant cinnamic ester moieties and photosensitizing groups

AbstractRates of photochemical reactions of polymers containing pendant cinnamic ester moieties and photosensitizing 4‐nitrophenoxy or 4‐nitro‐1‐naphthyloxy groups were determined in dilute benzene and tetrahydrofuran solutions. The rate of photodimerization of the polymers obeys first order kinetics in diluted solution and is affected by the type and content of pendant photosensitizing groups and by the structure of the polymer skeleton. By comparison of the rate of photodimerization of three homopolymers and six copolymers, it could be concluded that the polymers consisting of flexible segments have a higher rate of photodimerization than those made of rigid segments.

Cation binding properties of poly(crown ether)s with photodimerizable groups. Enhanced cation binding ability via a photochemical template effect

AbstractPolymers having both crown ether moieties as cation binding sites and cinnamic acid ester moieties as photodimerizable pendant groups were prepared. On irradiation with UV light the cinnamic acid ester groups of the polymers caused dimerization in dilute solution without formation of any insoluble material. Irradiation was carried out in THF and THF‐methanol (1 : 1 vol. ratio) in the absence and presence of cations as a template, respectively. The cation binding properties were investigated by means of the method of picrate salts extraction. The cation extractability of the photoreacted polymers was higher than that of the original polymers. Furthermore, the cation binding ability of the photoreacted polymers was less sensitive to temperature than that of the original polymers. The effect of the degree of photodimerization of the polymers, of the kind of cations used as a template during photodimerization of the polymers, and of the concentration of the template action on the extractability of polymers were investigated in detail.

Antilipolytic effect of p-myristyloxy-α-methylcinnamic acid (LK-903 acid) as a mechanism of the hypolipidemic action of its α-monoglyceride (LK-903)

In a study of the mechanism of hypolipidemic action of α-mono- p-myristyloxy-α'-methyl-cinnamoyl glycerol (LK-903), the hydrolyed cinnamic acid moiety (LK-903 acid) was found to inhibit in vitro the lipolysis manifested by rat epididymal adipocytes. Its antilipolytic action appears to be the result of inhibition of cyclic AMP formation in the fat cells in analogy with the mechanism of feedback inhibition of lipolysis by free fatty acids.

Suppressive effect of cycloheximide cinnamates on immune response and tumor growth in mice---a structure-activity relationship with respect to the substituent on the benzene ring of the cinnamic acid moiety.

The immunosuppressive and tumor-inhibitory activities in mice of cycloheximide cinnamates depended on the structure and position of a substituent on the benzene ring of the cinnamate moiety. When the levels of antibody production and tumor growth rate in the treated mice were analyzed statistically in relation to Hansch's hydrophobic constant π for each substituent, the π-response curves for the two biological responses were found to be similar to each other, suggesting that the two pharmacological activities depend on a common process which is influenced by the hydrophobicity of the cycloheximide cinnamates.