Hydroxy Phenyl Research Articles

RGD-conjugated In Situ forming hydrogels as cell-adhesive injectable scaffolds

In this study, a bioactive hydrogel was prepared from a chitosan derivative and Arg-Gly-Asp (RGD)-conjugated polypseudorotaxane, which is a cell-adhesive extracellular matrix. Chitosan was modified with 4-hydroxy phenyl acetic acid to obtain a water-soluble product for enzymatic cross-linking. Tyramine-terminated polypseudorotaxane (PRx) was prepared from the inclusion complex of a tyramine-terminated poly(ethylene glycol) backbone, and α-cyclodextrin (α-CD). Gly-Arg-Gly-Asp-Ser (GRGDS) was conjugated to the PRx using 4-nitrophenyl chloroformate (NPC) and partially carboxylated with succinic anhydride. The structure of the PRx-RGD and 4-hydroxylphenylacetamide chitosan (CHPA) was characterized by 1H NMR and FTIR spectroscopy. The RGD content in PRx-RGD was determined to be 0.19%. PRx-RGD and CHPA solution was crosslinked to form a bioactive hydrogel in the presence of horseradish peroxidase (HRP) and hydrogen peroxide (H2O2), which exhibited rapid gelation (∼20 sec). An in vitro cell culture was carried out with L929 mouse fibroblasts for 1 and 3 days. The results showed that fibroblasts adhered better and appeared to be more biocompatible on the RGD-conjugated hydrogel than the hydrogel without RGD. The combined results highlight the potential use of this bioactive hydrogel as an injectable scaffold in tissue engineering applications. Open image in new window

Study of thermal and electrical properties exhibited by two ferroelectric self assembly systems

Two series of inter hydrogen bonded ferroelectric liquid crystals have been isolated. In one of the series hydrogen bond is formed between p- n-alkyloxy benzoic acids and (S)-1,2-cholo-3-(4-hydroxy) phenyl propionic acid (CTy + nOBA) while in the other it is formed between p- n-alkyl benzoic acids and (S)-1,2-cholo-3-(4-hydroxy) phenyl propionic acid (CTy + nBA). Detailed synthetic route for the isolation of these compounds is discussed. Formation of the ferroelectric self assembly systems has been evinced through FTIR studies. The positional influence of oxygen atom is investigated from the thermal and electrical characterization of both the series. Polarizing optical microscope (POM) studies on CTy + nBA hydrogen bonded complexes reveals that they exhibit single phase variance while the other complex CTy + nOBA exhibit rich phase polymorphism. It is observed that the presence of oxygen atom enhances phase abundance. Phase diagrams for both the complexes are constructed from the DSC and POM studies. Dielectric relaxations and activation energies have been carried out for various phases in CTy + 8OBA and CTy + 8BA complexes. It has been observed that the oxygen atom originates type I relaxation process. Two molecular modeling have been assigned to account for the dielectric relaxation process observed in both the HBFLC series.

Optical and luminescence investigations of hydroxy substituted porphyrins in borate glasses

Hybrid borate glasses containing various hydroxy phenyl derivatives of porphyrin were prepared by melt quenching technique. The effect of hydroxy functional groups on the photophysical properties was investigated by means of optical absorption, steady-state fluorescence and time resolved fluorescence spectroscopy. The optical absorption spectra show red shift in Soret and Q-band with increase in the number of –OH groups on the phenyl ring of the porphyrin. The steady-state emission spectrum shows strong S 2→S 0 emission around 498–540 nm and red shifted S 1→S 0 emission around 669–803 nm. Time resolved fluorescence shows three exponential decay with τ 1 = 11 ± 2 ps (64.56%), τ 2 = 0.16 ± 0.1 ns (24.54%), and τ 3 = 2.94 ± 0.1 ns (10.9%) for 2 mg of H 2OHP doped glass. The appearance of strong S 2→S 0 emission indicates that the structure of porphyrin inherently modified in the glass matrix. The boron ions of the borate network interact at the central core of the porphyrin and also form oxy bridge at the periphery. The effect of porphyrin concentration on photophysical properties and the possible structures of porphyrin in the borate glass matrix were investigated.

One-pot synthesis of novel ladder type condensation polymers via condensation reactions of dihydroxyaromatic compounds and 2,5-dimethoxytetrahydrofuran

The one-pot polycondensation of dihydroxyaromatic compounds such as hydroquinone, 2,2-di(4-hydroxy phenyl) propane (Bisphenol A), 4,4′-dihydroxybiphenyl, dihydroxynaphthalenes (1,5- and 2,6-) with 2,5-dimethoxytetrahydrofuran as a reactive protected 1,4-dicarbonyl compound using trifluoroacetic acid as both solvent and condensing agent leads to condensation polymers having linear and ladder structure with high thermal stability. Optimal conditions for polycondensation were obtained via study of the model compounds. All polymers were obtained in high yields and with varying molecular weights ( η = 0.16–0.31 dl/g). The structure of the polymers were characterized by NMR, FTIR spectroscopies and TG.

Life Extension by Diet Restriction and N-Acetyl-L-Cysteine in Genetically Heterogeneous Mice

We used a heterogeneous stock of mice-UM-HET3, the first generation offspring of CByB6F1/J and C3D2F1/J parents-to test effects of six antiaging treatments on life span. In the first report of diet restriction in a structured, segregating heterogeneous population, we observed essentially the same increases in mean and maximum life span as found in CByB6F1/J hybrid positive controls. We also report results of treatment with N-acetyl-L-cysteine started at 7 months, and aspirin, nitroflurbiprofen, 4-hydroxy phenyl N-tert-butyl nitrone, and nordihydroguaiaretic acid, all started at 16-18 months. Only male UM-HET3 mice receiving N-acetyl-L-cysteine had significantly increased life span, and this may have been due to treatment-related inadvertent diet restriction. The other agents had no significant effects on life span. The use of UM-HET3 mice helps assure that these results are not the result of unresponsiveness of a single genotype but that they more broadly represent laboratory mice.

Synthesis and Antifungal Activities of 5‐(o‐Hydroxy phenyl)‐2‐[4′aryl‐3′chloro‐2′azetidinon‐1‐yl]‐1,3,4‐thiadiazole

New series of 5‐(o‐hydroxy phenyl)‐2‐[4′aryl‐3′chloro‐2′azetidinon‐1‐yl]‐1,3,4‐thiadiazole have been synthesized and the structures of the new compounds were established on the basis of IR, 1H NMR spectral data. In vitro antifungal activity (MIC activity) was evaluated and compared with standard drugs of ketoconazole. Compounds 3c in the series has shown interesting antifungal activity against both C. albicans and A. niger fungus. In the gratifying result, most of the compounds were found to have moderate antifungal activity.

One-Pot Synthesis of Five and Six Membered N, O, S-Heterocycles Using a Ditribromide Reagent

In a one-pot procedure, bromine less brominating reagent 1,1'-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) has been utilized as an efficient desulfurizing agent for the construction of a library of heterocycles containing N, O, and S starting from aryl/alkyl isothiocyanates. In this approach, aryl/alkyl isothiocyanate reacts with o-phenylenediamine (o-PD), o-aminophenol, and o-aminothiophenol to form their monothiourea which on desulfurization with EDPBT led to the formation of corresponding 2-aminobenzimidazoles, 2-aminobenzoxazoles, and 2-aminobenzothiazoles, respectively. An interesting regioselectivity was observed for unsymmetrical thiourea having a naphthyl moiety on the one side and an ortho amino or an ortho hydroxy phenyl group on the other side giving a completely different product which is mainly dependent on the nature of the nucleophiles (-OH or -NH(2)). Further, the bis-thioureas resulted from the aliphatic 1,2-diamine with 2 equiv of aryl isothiocyanates on treatment with EDPBT gave imidazolidenecarbothioamides, whereas bis-thioureas resulted from aromatic 1,2-diamine yielded benzimidazoles with concurrent expulsion of an isothiocyanate unit. This method is simple and applied to various substrates which are amenable to bromination that reveals the desulfurizing ability of EDPBT predominating over its brominating ability. Finally, the spent reagent EDPDB can be recovered, regenerated, and reused without any loss of activity.

Microwave Assisted Synthesis and Antimicrobial Activities of Some 2‐Amino‐4‐aryl‐3‐cyano‐6‐(4’‐hydroxy phenyl)‐pyridines

4’‐Hydroxy chalcones were treated with malononitrile in the presence of ammonium acetate under solventless microwave assisted condition to get 2‐amino‐4‐aryl‐3‐cyano‐6‐(4’‐hydroxy phenyl)‐pyridines. The prepared compounds were screened for their antimicrobial activity; some of them have exhibited promising antimicrobial activity.

Hepatotoxicity of Schiff bases derived from benzoin salicylaldehyde, aminophenol and 2,4 dinitrophenyl hydrazine

The Journal of the National Science Foundation of Sri Lanka publishes the results of research in all aspects of Science and Technology. The journal also has a website at http://www.nsf.gov.lk/. 2021 Impact Factor: 0.682The JNSF provides immediate open access to its content on the principle that making research freely available to the public supports a greater global exchange of knowledge.

ChemInform Abstract: Sodium Perborate: A Facile Synthesis of 1,2-Benzisoxazole 2-Oxides.

Abstract An efficient and convenient methodology has been developed for the conversion of 2-hydroxy phenyl ketoxime to 1,2-benzisoxazole 2-oxide with sodium perborate (SPB) in glacial acetic acid under mild reaction conditions. Interestingly when the reaction was carried out under reflux condition deoximation was observed in quantitative yield.

A comparison of the in vitro biotransformation of (–)‐epicatechin and procyanidin B2 by human faecal microbiota

The catabolism by human faecal microbiota of (-)-epicatechin (1) (2, 3-cis stereochemistry) and its dimer pure procyanidin B2 (2), has been compared using a static in vitro culture model. The catabolites were characterised by LC-MS(n), UV absorption and relative retention time, and quantified relative to standards. No more than approximately 10% of procyanidin B2 (2) was converted to epicatechin (1) by scission of the interflavan bond. Five phenolic acid catabolites (M(r)<290) were unique to 2, and ten phenolic acid catabolites (M(r)<290) were common to both substrates. The dominant catabolites (> or =24 h incubation) were 5-(3'-hydroxy phenyl) valeric acid (9), 3-(3'-hydroxyphenyl) propionic acid (10) and phenyl acetic acid (12) (maximum yields 27.4+/-4.2, 38.2+/-4.2, 22.7+/-2.9%, respectively, from 1 and 9.4+/-1.2, 52.8+/-2.1, 28.8+/-1.6%, respectively, from 2). Substrate 2 was degraded twice as rapidly as 1. Evidence is presented for the production of previously unreported catabolites of 2 that retain the flavanol A-ring and the C4-->C8 interflavan bond. It was confirmed that catabolism favoured removal of the 4'-hydroxyl rather than the 3'-hydroxyl group and that both beta-oxidation and alpha-oxidation occurred.

N-(2-hydroxy phenyl) acetamide inhibits inflammation-related cytokines and ROS in adjuvant-induced arthritic (AIA) rats

The present study was carried out to study the anti-arthritic and anti-inflammatory activity of N-(2-hydroxy phenyl) acetamide in adjuvant-induced arthritis in adult female Sprague Dawley rats. During experimental period, body weight and paw oedema volume were observed. At the end of each experiment, plasma and serum samples were collected and used for estimation of pro-inflammatory cytokines IL-1β and TNF-α and oxidative stress markers i.e., nitric oxide, peroxide and GSH. Our results suggested that, the reduction in body weight and increase in paw oedema volume were significantly retarded in the AIA rats receiving 5 mg/kg and 10 mg/kg doses of N-(2-hydroxy phenyl) acetamide as compared to diseased control animals. The serum levels of IL-1β and TNF-α were reduced as compared to those in the diseased control group. Treatment with N-(2-hydroxy phenyl) acetamide also altered oxidative stress markers in relation to its anti-inflammatory activity. Based on our results, it can be concluded that N-(2-hydroxy phenyl) acetamide possesses promising anti-arthritic property.

Synthesis of 7-[4-alkoxy-3-methoxy(hydroxy)phenyl]-10,11-dihydrobenzo[c]acridin-8(7H,9H,12H)-ones and 4-(8-oxo-7,8,9,10,11,12-hexahydrobenzo[c]acridin-7-yl)-2-methoxy(ethoxy)phenyl esters of carboxylic acids

Reactions of azomethines (Schiff bases) prepared from vanillin and vanillal ethers and 1-naphthylamine with cyclohexane-1,3-dione in butanol afforded in 40–64% yields 7-[4-alkoxy-3-methoxy(hydroxy)phenyl]-10,11-dihydrobenzo[c]acridin-8(7H,9H,12H)-ones and 4-(8-oxo-7,8,9,10,11,12-hexahydrobenzo[C]acridin-7-yl)-2-methoxy(ethoxy)phenyl esters of carboxylic acids. The reaction products presumably formed by the rearrangement of the azomethine adduct with the cyclohexane-1,3-dione proceeding by the type of Hofmann-Martius rearrangement. The structure of compounds synthesized was confirmed by the elemental analysis, UV, IR, and 1H NMR spectra.

Synthesis and characterization of three covalently linked porphyrin-phthalocyanine pentamers with nucleophilic substitution

In this paper the synthetic methods of three covalently linked porphyrin-phthalocyanine heteropentamers, containing four units of porphyrin linked to a central phthalocyanine (Mpor-LPc; M = 2H, Fe, L = Zn, Fe), are described. The synthetic strategy is on the basis of nucleophilic substitution reactions between [1,8,15,22-tetra nitro phthalocyanines] and [5-(4-hydroxy phenyl)-10,15,20-triphenyl porphyrins] as the phenolic alcohols. Porphyrins are linked with oxygen as spacer through meso position of phenyl group to phthalocyanines. These macromolecules were characterized by 1H NMR, UV–Vis, IR, fluorescence and mass spectroscopy. The electronic absorption spectrums of the hetero-dyad systems changed significantly upon coupling and showed a great red shift in the phthalocyanine Q-bands. These changes confirm the electron-donating effects of the porphyrin units and the extension of conjugated п-systems. The emission spectra of the products supports intramolecular energy and charge transfer between the sub-units.

Novel pH-sensitive hydrogels for colon-specific drug delivery

The purpose of this study is to develop novel intestinal specific drug delivery systems with pH-sensitive swelling and drug release properties. Acryloyl ester of 5-[4-(hydroxy phenyl) azo] salicylic acid (HPAS) as an azo derivative of 5-amino salicylic acid (5-ASA) was prepared under mild conditions. The HPAS was covalently linked with acryloyl chloride, abbreviated as APAS. Cubane-1,4-dicarboxylic acid (CDA), linked to two 2-hydroxyethyl methacrylate (HEMA) groups, was the cross-linking agent (CA). Methacrylic-type polymeric prodrugs were synthesized by free radical copolymerization of methacrylic acid, poly(ethyleneglycol monomethyl ether methacrylate), and APAS in the presence of cubane cross-linking agent. The effect of copolymer composition on the swelling behavior and hydrolytic degradation were studied in simulated gastric (SGF, pH 1) and intestinal fluids (SIF, pH 7.4). The composition of the cross-linked three-dimensional polymers was determined by FTIR spectroscopy. The hydrolysis of drug–polymer conjugates was carried out in cellophane membrane dialysis bags containing aqueous buffer solutions (pH 1 and pH 7.4) at 37°C. Detection of the hydrolysis product by UV spectroscopy shows that the azo prodrug (HPAS) was released by hydrolysis of the ester bond located between the HPAS and the polymer chain. Drug release studies showed that the increasing content of MAA in the copolymer enhances hydrolysis in SIF. These results suggest that pH-sensitive systems could be useful for preparation of a muccoadhesive system and controlled release of HPAS as an azo derivative of 5-amino salicylic acid (5-ASA).

Determination of molybdenum(VI) by differential pulse polarographic technique using 4-(2-hydroxy phenyl ethaminodiol), benzene-1,3-diol(4-2-HPEDB-1,3,D)

A novel analytical reagent 4-(2-hydroxy phenyl ethaminodiol), benzene-1,3-diol(4-2-HPEDB-1,3,D) was synthesized for the determination of molybdenum(VI). The present paper reveals the detailed study of electroanalytical behaviour for [Mo-(4-2-HPEDB-1,3,D)] complex under optimized conditions. The peak obtained for [Mo-(4-2-HPEDB-1,3,D)] prevent the interference of foreign ions which shows the sensitivity of the proposed method. The linearity was maintained at the concentration range of 0.5–200μg/mL at pH 4.5 with correlation factor 0.9997. The present method was successfully applied for the analysis of molybdenum(VI) in biological fluids and plant material. The results obtained from the proposed method show good agreement with reference method.

Comparison of influence of aerobic exercise, in water walking and yogic exercise, on 3-methoxy –4-hydroxy phenyl glycol-sulfate in depressed girls

Depression is a clinical disorder distinguished by physiological and psychological markers. Some studies have indicated that during depression some neural chemical transmitters including epinephrine are reduced. It seems that these chemical changes can cause depression symptoms. 3-metoxy-hydroxyphenyl glycol-sulphate (MHPG) is a metabolite of epinephrine that released from presynaptic nerve terminals of central nervous system and became sulphate in brain. It cross the blood-brain barrier and showed as a sulphate combination in urine. The propose of this proposal, was to determine the effect of 8 weeks of aerobic exercise, walking in water and yogic exercise on urine MHPG sulphate in the depressed girls.

A study of field induced transitions (FiT) in the nematic phase of an inter hydrogen bonded ferroelectric liquid crystal

A novel series of hydrogen bonded ferroelectric liquid crystals (HBFLC) have been isolated. Hydrogen bond is formed between non mesogen chiral ingredient (S)-1, 2–cholo-3-(4-hydroxy) phenyl propionic acid and mesogenic p-n alkoxy benzoic acids. Phase diagram is constructed from the transition temperatures obtained by differential scanning calorimetry (DSC) and polarizing optical microscopic (POM) studies. Thermal and electrical properties exhibited by a hydrogen bonded complex namely (S)-1,2–cholo-3-(4-hydroxy)phenyl propionic acid with octyloxy benzoic acid (CTy + 8BA) are discussed. Observation of dielectric hysteresis in CTy + 8BA makes it more suitable for device applications. Salient feature of the present work is observation of a field induced transitions in nematic phases pertaining to the above complex designated as FiT. This phenomenon has been confirmed by optical textures of POM, helicoidal measurements, optical intensity and dielectric studies. Four threshold electrical field values are noticed which in turn contributed to four new phases (E 1, E 2, E 3 and E 4) induced by electric field and helical pitch measurements supports the above observation. FiT is reversible in the sense that when applied field is removed the original texture is restored.

Synthesis and characterization of polyesters from 2,3-bis (4′-hydroxy phenyl) quinoxaline and 2,3-bis (2′-hydroxynaphthalene-6′-yl) quinoxaline

Abstract Two bisphenols containing pendant, quinoxaline moiety; 2,3-bis (4′-hydroxy phenyl) quinoxaline (BHPQ) and 2,3-bis (2′-hydroxynaphthalene-6′-yl) quinoxaline (BHNQ) were synthesized and characterized by FT-IR, 1 H, 13 C NMR and mass spectrometry. Aromatic polyesters and copolyesters were prepared by interfacial polymerization from BHPQ or BHNQ and isophthaloyl chloride or terephthaloyl chloride or a mixture of different mole proportions of (IPC + TPC). These polyesters and copolyesters were characterized by spectroscopic technique, viscosity measurement, solubility, thermal stability, DSC and XRD. Polymers had moderate to high molecular weights as evidenced by the inherent viscosities in the range 0.35–0.78 dL/g for BHPQ series and 0.27–0.52 dL/g for BHNQ series. BHPQ polyesters and copolyesters dissolved in m-cresol, NMP and conc. H 2 SO 4 whereas, BHNQ polyesters and copolyesters were readily soluble in NMP, DMAc, (TCE + phenol) and partly soluble in solvent like CHCl 3 , pyridine, etc. Wide angle X-ray diffraction (WAXD) results showed that introduction of quinoxaline moiety into polymer chain and aromatic phenyl/rigid naphthyl structures lead to crystalinity. Differentional scanning calorimetry of BHNQ polyesters showed the glass transition temperatures in the range of 131–151 °C. BHPQ polyesters did not show any weight loss below 330 °C and retained 27–55% weight at 900 °C when investigated by TGA under nitrogen atmosphere demonstrating good thermal stability BHNQ derived polyesters showed initial decomposition temperatures in range 211–234 °C. The structure–property relationships for the mentioned polyesters are analyzed, as these polyesters are of interest as materials for electronics, microelectronics and membrane separation.

Effect of carbon steel microstructure and molecular structure of two new Schiff base compounds on inhibition performance in 1M HCl solution by DC, SEM and XRD studies

In this investigation, attempts have been made to study the inhibitive effect of N,N′-ortho-phenylen acetyle acetone imine (S1) and 4-[(3-{[1-(2-hydroxy phenyl) methylidene] amino} propyl) ethanemidol]-1,3-benzenediol (S2) in the concentration range of 50–400 ppm for mild steel with two different microstructures resulted from two different heat treatments (annealed (A) and quenched and tempered (Q&T)) in 1 M hydrochloric acid solution. Both Schiff bases acted as a mixed type inhibitors. The S1 inhibitor for both microstructures showed better inhibition efficiency than S2. The A samples indicated slightly less corrosion than Q&T samples in 1 M HCl solution in absence of inhibitor due to the formation of duplex γ-Fe 2 O 3 /Fe 3 O 4 .