Hydroxyphenyl Group Research Articles

Ethyl (E)-3-(2-hydroxyphenyl)-2-(morpholinocarbonyl)propenoate.

The title compound, C16H19NO5, crystallizes as a centrosymmetric dimer through strong O-H...O hydrogen-bonding interactions between the hydroxyphenyl and morpholinocarbonyl groups. The morpholinocarbonyl group is almost perpendicular to the propenoate moiety. Electron delocalization in the N-C(=O) fragment leads to the formation of hydrogen-bonded S(5) ring motifs through C-H...O interactions.

Identification of functionally important residues in the pyridoxal-5'-phosphate-dependent catalytic antibody 15A9.

Antibody 15A9 is unique in its ability to catalyze the transamination reaction of hydrophobic D-amino acids with pyridoxal-5'-phosphate (PLP). Both previous chemical modification studies and a three dimensional (3-D) homology model indicated the presence of functionally important tyrosine residues in the antigen-binding cavity of antibody 15A9. To gain further insight into the hapten, ligand binding, and catalytic mechanism of 15A9, all tyrosine residues in the complementarity-determining regions (CDRs) and the single arginine residue in CDR3 of the light chain were subject to an alanine scan. Substitution of Tyr(H33), Tyr(L94), or Arg(L91) abolished the catalytic activity and reduced the affinity for PLP and N(a)-(5'-phosphopyridoxyl)-amino acids, which are close analogues of covalent PLP-substrate adducts. The Tyr(H100b)Ala mutant possessed no detectable catalytic activity, while its affinity for each ligand was essentially the same as that of the wild-type antibody. The binding affinity for the hapten was drastically reduced by a Tyr(L32)Ala mutation, suggesting that the hydroxyphenyl group of Tyr(L32) participates in the binding of the extended side chain of the hapten. The other Tyr --> Ala substitutions affected both binding and catalytic activity only to a minor degree. On the basis of the information obtained from the mutagenesis study, we docked N(alpha)-(5'-phosphopyridoxyl)-D-alanine into the antigen-binding site. According to this model, Arg(L91) binds the alpha-carboxylate group of the amino acid substrate and Tyr(H100b) plays an essential role in the catalytic mechanism of antibody 15A9 by facilitating the Calpha/C4' prototropic shift. In addition, the catalytic apparatus of antibody 15A9 revealed several mechanistic features that overlap with those of PLP-dependent enzymes.

Biphenyl derived Schiff-base vanadium(V) complexes with pendant OH-groups--structure, characterization and hydrogen peroxide mediated sulfide oxygenation.

A series of mononuclear oxovanadium(v) complexes of tridentate Schiff bases HL(1)-HL(4) and H(2)L(5)-H(2)L(8) derived from 6-phenylsalicylaldehyde and 6-(2-hydroxyphenyl)salicylaldehyde and four different amines was synthesized. The systematically selected ligands contain aliphatic or aromatic nitrogen, or alkoxy- and phenoxy-oxygen as third donor atom. The complexes were characterised by spectroscopic methods in solution and the solid state. Single-crystal X-ray analyses were performed with VO(2)L(1)(), VO(2)L(3)x1/2EtOH (), VO(2)L(4)(), VO(OiPr)L(7)xiPrOH, VO(OiPr)L(8) and H(2)L(8). For all compounds the vanadium(v) cores contain distorted tetragonal pyramidal geometry around the dioxo- and oxovanadium site at which the N(2)O- and NO(2)-donor ligands bind equatorially. Complexes and display intramolecular hydrogen bonding of the pendant hydroxyphenyl group to a coordinated oxygen trans to a nitrogen atom and therefore serve as suitable models for the native site of vanadium dependent haloperoxidases. Variable-temperature (1)H NMR spectra revealed significant hydrogen bond interaction in acetonitrile solution. In situ prepared catalysts are active for hydrogen peroxide mediated oxygenation of ethyl phenyl sulfide and showed complete conversion of the substrate to ethyl phenyl sulfoxide, together with small amounts of the corresponding sulfone, as detected by GC/MS after 10 min. The complex of H(2)L(7) turned out to be most efficient while HL(1) and HL(2) were completely inactive. Catalysis is supported by the pendant OH group in the complex of HL(3), the catalyst is twice as active as the complex of HL(4).

2'-Hydroxy-4"-dimethylaminochalcone.

The title compound, 3-[4-(dimethylamino)phenyl]-1-(2-hydroxyphenyl)prop-2-en-1-one, C(17)H(17)NO(2), is a chalcone derivative substituted by 2'-hydroxyl and 4"-dimethylamino groups. The crystal structure indicates that the aniline and hydroxyphenyl groups are nearly coplanar, with a dihedral angle of 10.32 (16) degrees between their phenyl rings. The molecular planarity of this substituted chalcone is strongly affected by the 2'-hydroxyl group.

Hydroxyphenyl substituted tetrathiafulvalene vinylogues affording stable cation radical salts with unusual crystal structures

TTF vinylogues containing hydroxyphenyl groups were newly prepared. They are stronger electron donors than BEDT-TTF and afforded their cation radical salts as single crystals upon electrochemical oxidation. X-Ray structure analysis has revealed their unusual crystal structures, where π-overlapping and hydrogen bonding play a crucial role in constructing them.

THERMOREVERSIBLE GELS OF AQUEOUS SOLUTIONS OF POLY(N-VINYLPYRROLIDONE)-POLY(4-VINYLPHENOL) BLENDS

Thermoreversible gel-sol transitions are investigated for aqueous solutions of blends of poly(N-vinylpyrrolidone) (PVPr) with poly(4-vinyphenol) (PVPh). It is found that aqueous solutions of PVPr-PVPh blends containing a small amount of PVPh form gels due to hydrogen-bonding between the hydroxyphenyl groups of PVPh and the carbonyl groups of PVPr. In addition, the gels show a thermoreversible gel-sol transition because of the thermoreversible nature of cross-links. The gel-sol transition temperature of the systems rises with increasing PVPh content in PVPr/PVPh blends and decreasing water/blends (w/w) ratio. The heat of fusion of PVPr-PVPh gels results in relatively small absolute values due to repulsion between PVPh and distilled water.

Hyperbranched poly(arylene ether phosphine oxide)s

New AB 2 and A 2 B monomers, bis(4-fluorophenyl)-4'-hydroxyphenylphosphine oxide and bis(4-hydroxyphenyl)-4'-fluorophenyl-phosphine oxide were prepared and converted to corresponding hyperbranched poly(arylene ether phosphineoxide)s with hydroxyphenyl and fluorophenyl end functional groups. While the dihydroxy monomer gave a low molecular weight polymer, the difluoro monomer produced a high molecular weight hyperbranched polymer. The glass transition temperature of the obtained polymers was 266°C and 230°C, and 5% weight loss temperature was 491 °C and 391 °C, respectively. The fluorophenyl-terminated hyperbranched polymer was soluble in CHCl 3 , but the hydroxyphenyl-terminated polymer was not soluble in CHCl3 even though it has lower molecular weight than the fluorophenyl-terminated polymer, indicating that properties of the hyperbranched polymers markedly depend on end functional groups as well as their molecular weight.

1-(2,4-Dinitrophenyl)-3-(2-hydroxyphenyl)-1H-pyrazole-4-carbaldehyde

In the crystal of the title compound, C 16 H 10 N 4 O 6 , the dinitrophenyl and hydroxyphenyl groups are oriented at angles of 43.8(1) and 28.0 (1)°, respectively, with respect to the pyrazole ring. The internal C-C-C ring angles at the o- and p- positions, where NO 2 is bonded, are 121.6(2) and 122.3 (2)°. The crystal structure and packing are stabilized by O-H…N and C-H…O hydrogen bonds.

Phase Diagram of Poly(4-vinylphenol)−N,N-Dimethyloctadecylamine Mixture

The phase diagram of poly(4-vinylphenol)−N,N-dimethyloctadecylamine (PVPh−NDOA) mixture is investigated by X-ray diffraction measurements and optical microscopy. In the low-temperature region PVPh−NDOA mixtures take the mesoscopically ordered phase like a comb-shaped polymer above the melting temperature of the crystal of PVPh−NDOA aggregates. With elevating temperature PVPh−NDOA mixtures undergo an order−disorder phase transition that is a characteristic phase transition in block- or comb-shaped polymers and take homogeneous single phase. Furthermore, at higher temperatures PVPh−NDOA mixtures show the LCST-type phase transition and macroscopically separate into two homogeneous phases. These complex phase behavior in the PVPh−NDOA mixture is explained in relation to the balances of association between the hydroxyphenyl group of PVPh and the dimethylamino group of NDOA, repulsion between PVPh and the octadecyl group of NDOA, and the variation of the entropy contribution with varying temperature.

NPY Y 1 antagonists: structure–activity relationships of arginine derivatives and hybrid compounds with arpromidine-like partial structures

Previously, ω-guanidino- and ω-aminoalkanamides, structurally derived from arpromidine-like histamine H 2 receptor agonists, were reported as novel neuropeptide Y Y 1 antagonists. Regardless of the backbone, they resemble BIBP 3226, an argininamide with high NPY Y 1 receptor affinity and selectivity, with respect to nature and arrangement of the `terminal' diaryl, guanidine, and hydroxyphenyl groups. Hybrid compounds were synthesized combining the argininamide backbone of BIBP 3226 or partial structures derived from the C-terminal dipeptide of NPY with characteristic substructures of arpromidine- or amide-type NPY antagonists. Additionally, some analogs of BIBP 3226 with reduced flexibility were prepared. Structure–activity relationships indicate that, in contrast to alkanamides, homologs and/or isomers of BIBP 3226 with vicinal arrangement of the phenyl rings have decreased Y 1 antagonistic activity (Ca 2 +-assay in HEL cells). Replacement of the hydroxybenzyl group by an imidazole ring further decreases activity. It is concluded that the binding sites of NPY antagonists with one and with two basic groups are not identical. Analogs with a rigid tetrahydro-2-benzazepine or an indan group in place of the benzyl moiety in BIBP 3226 are active, indicating the role of the OH group and supporting the model proposed for the interaction of BIBP 3226 with the Y 1 receptor.

Interaction between Hydroxyphenyl-Containing Phosphate and Styrenic Resin

Phosphates having ΔSP of 1 to 2 from a given resin were found to have partial compatibility with the resin. Such phosphates promote resin plastication and thus function as flow modifiers during molding while their partial incompatibility serves to maintain the inherent heat resistance of the resin in molded products. It was found in particular that hydroxyphenyl-containing phosphates such as resorcinyl diphenyl phosphate function not only as flame retardants but also as flow modifiers for styrenic resin compositions, in which they improve flowability without causing reduced impact resistance or heat resistance. Investigation of phosphate/styrenic resin compatibility by FT-IR spectroscopic and viscoelastic analysis indicated strong interaction by the phosphate containing no hydroxyphenyl group, but significantly weaker interaction by the hydroxyphenyl-containing phosphate.

Effects of primer-concentration on uronosyl-epimerization and sulfation patterns in p-hydroxyphenyl-O-beta-D-xylopyranoside-primed galactosaminoglycans produced by skin fibroblasts.

By supplying skin fibroblasts with different concentrations of the galactosaminoglycan chain-primer p-hydroxyphenyl-O-beta-D-xylopyranoside we have produced and recovered glycan-chains that were subsequently radio-iodinated in the hydroxyphenyl group and subjected to sequence analysis by using graded enzymic treatment followed by a combination of gel chromatography and electrophoresis. Fragments extending from the tagged reducing end to the cleavage-point were identified and quantified. Degradation by chondroitin B lyase of chains primed at 0.1 or 0.5 mM xyloside gave profiles indicating a periodic and wave-like distribution of iduronate-containing repeats, with high incidence around positions 2, 5 and onwards, whereas in chains produced at 1.0 mM xyloside the incidence of iduronate was similar in positions 1-4 and then declined. Degradation by chondroitin AC lyase indicated a high incidence of glucuronate in or near the linkage-region. There was a relatively uniform degree of sulfation in chains primed at low xyloside concentration, whereas chains primed at 1.0 mM xyloside gave very heterogeneous charge-patterns in all segments of the chain, including the linkage-region, giving the impression that adequate sulfation, probably at C-4 and at the first opportunity, is necessary to obtain an ordered and periodic epimerization pattern.

Synthesis and evaluation of positive‐acting photosensitive polyimides with phenol moiety

AbstractNovel positive‐acting photosensitive polyimide resists (1) developable with an alkaline aqueous solution were prepared. The resists consisted of a naphthoquinone diazide (NQ) and a polyamic acid bearing hydroxyphenyl groups (PA). The hydroxyphenyl moieties are newly incorporated by adding 2‐N,N‐dimethylaminoethyl‐3‐hydroxybenzoate (m‐PEA) or 2‐N,N‐dimethylaminoethyl‐4‐hydroxybenzoate (p‐PEA) to the polyamic acid, through ionic interaction between the carboxylic acid and the amine. The NQ acts as a solution inhibitor for the PA by the interaction with the hydroxyphenyl moiety. This system is similar to that of phenol‐novolac resin/NQ resists currently conducted in the fabrication of the Large Scale Integrated circuit (LSI). The resist (1) is exposed to a G‐line and is developed with tetramethylammonium hydroxide aqueous solution to provide fine patterns, proving that the (1) is compatible with LSI‐production lines currently applied. A novel polyamic acid‐curing mechanism found in the course of this study is also reported. © 1995 John Wiley & Sons, Inc.

Reaction of Alkyne Having Hydroxyphenyl Group with Mo(CO)6

Abstract The reaction of m-and p-hydroxyphenylpropyne, 1a and 1b, with Mo(CO)6 (5 mol%) affords metathesis products, 2a and 2b, in 78% and 14% (conversion yield, 78%) yields, respectively. However, o-hydroxyphenylpropyne 1f gave trimerization product 4 in 65% yield.

Cyclotheonamide derivatives: Synthesis and thrombin inhibition. Exploration of specific structure-function issues

Macrocyclic pentapeptide analogues (5–9) of the sponge natural product cyclotheonamide A (CtA, 3) were prepared by means of our convergent [3 + 2] synthetic protocol, in which a late-stage primary amine group is available for substitution (Maryanoff et al. Proc. Natl Acad. Sci. U.S.A. 1993, 90, 8048). These analogues, as well as CtA and cyclotheonamide B (CtB, 4), were examined for their ability to inhibit the serine protease α-thrombin, in comparison with suitable reference standards. We characterized Michaelis-Menten and slow-binding kinetics for the cyclotheonamide derivatives. An attempt was made to utilize the unoccupied hydrophobic S 3 subsite of thrombin via analogues 5 and 6. Also, removal of the hydroxyphenyl group, which is thought to be involved in an aromatic stacking interaction with Trp 60D of thrombin, was explored via analogue 9. The importance of the α-keto and olefin groups was examined via 7 and 8, respectively. The relationship of structure and function with the analogues proved to be less predictable than anticipated.

P-198 Cytoprotective effect of hepatocyte growth factor (HGF) for acute liver injury in HGF transgenic mice

Iron chelators such as deferiprone, deferoxamine (DFO) and ICL670 (deferasirox) have previously been shown to display in vitro and/or in vivo antimalarial activities. To gain further insight in their antimalarial mechanism of action, their activities on inhibition of β-hematin formation and on both peroxidative and glutathione (GSH)-mediated degradation of hemin were investigated. Neither deferiprone nor DFO were able to inhibit β-hematin formation while ICL670 activity nearly matched that of chloroquine (CQ). Peroxidative degradation of hemin was also only strongly inhibited by both CQ and ICL670, the latter being significantly more efficient at pH 5.2. All iron chelators displayed minor, if any, inhibitory activity on GSH-mediated degradation of hemin. Discrepancies in the results obtained for the three iron chelators show that iron chelation is not the main driving force behind interference with heme degradation. Deferiprone, DFO and ICL670 share little structural community but both ICL670 and antimalarial ursolic acid derivatives (previously shown to block β-hematin formation and the peroxidative degradation of hemin) have hydrophobic groups and hydroxyphenyl moieties. These similarities in structures and activities further back up a possible two-step mechanism of action previously proposed for ursolic acid derivatives (Mullié et al., 2010) implying (1) stacking of an hydrophobic structure to hemin and (2) additive protection of hemin ferric iron from H2O2 by hydroxyphenyl groups through steric hindrance and/or trapping of oxygen reactive species in the direct neighborhood of ferric iron. These peculiar antimalarial mechanisms of action for ICL670 warrant further investigations and development.

P-200 Interaction between hepatocyte and kupffer cell: From the viewpoint of biliary excretion of lipopolysaccharide in the liver

Iron chelators such as deferiprone, deferoxamine (DFO) and ICL670 (deferasirox) have previously been shown to display in vitro and/or in vivo antimalarial activities. To gain further insight in their antimalarial mechanism of action, their activities on inhibition of β-hematin formation and on both peroxidative and glutathione (GSH)-mediated degradation of hemin were investigated. Neither deferiprone nor DFO were able to inhibit β-hematin formation while ICL670 activity nearly matched that of chloroquine (CQ). Peroxidative degradation of hemin was also only strongly inhibited by both CQ and ICL670, the latter being significantly more efficient at pH 5.2. All iron chelators displayed minor, if any, inhibitory activity on GSH-mediated degradation of hemin. Discrepancies in the results obtained for the three iron chelators show that iron chelation is not the main driving force behind interference with heme degradation. Deferiprone, DFO and ICL670 share little structural community but both ICL670 and antimalarial ursolic acid derivatives (previously shown to block β-hematin formation and the peroxidative degradation of hemin) have hydrophobic groups and hydroxyphenyl moieties. These similarities in structures and activities further back up a possible two-step mechanism of action previously proposed for ursolic acid derivatives (Mullié et al., 2010) implying (1) stacking of an hydrophobic structure to hemin and (2) additive protection of hemin ferric iron from H2O2 by hydroxyphenyl groups through steric hindrance and/or trapping of oxygen reactive species in the direct neighborhood of ferric iron. These peculiar antimalarial mechanisms of action for ICL670 warrant further investigations and development.

Conformationally biased tri- and di-basic 1,3,5-triazacyclohexyl ligands

The biased ligand cis-cis-2,4,6-trimethyl-1,3,5-triaminocyclohexane is weakly basic and may be converted into di-and tri-basic complexing agents bearing hydroxyphenyl, carboxylate or phosphinate groups; an unusual tricyclic bis-aminal intermediate hydrolyses in acidic media to yield a stable bicyclic amidine via an intramolecular hydride transfer mechanism.

Oxidation of hydroxycinnamic acid and hydroxycinnamyl alcohol derivatives by laccase and peroxidase. Interactions among p‐hydroxyphenyl, guaiacyl and syringyl groups during the oxidation reactions

Fungal laccase oxidized derivatives of hydroxycinnamic acid. The rates decreased in the order sinapic acid > ferulic acid ≥p‐coumaric acid. The laccase oxidized sinapyl alcohol faster than coniferyl alcohol. The rates of oxidation of the hydroxycinnamic acid derivatives by an isoenzyme of peroxidase from horseradish decreased in the order p‐coumaric acid > ferulic acid ≥ sinapic acid. The peroxidase oxidized coniferyl alcohol much faster than sinapyl alcohol. The laccase and the peroxidase predominantly oxidized (a) ferulic acid in a reaction mixture that contained p‐coumaric acid and ferulic acid, (b) sinapic acid in a mixture of p‐coumaric acid plus sinapic acid, and (c) sinapic acid in a mixture of ferulic acid plus sinapic acid. In a reaction mixture that contained both coniferyl and sinapyl alcohols, both fungal laccase and horseradish peroxidase predominantly oxidized sinapyl alcohol. From these results, it is concluded (1) that the p‐hydroxyphenyl radical can oxidize guaiacyl and syringyl groups and produce their radicals and (2) that the guaiacyl radical can oxidize the syringyl group under formation of its radical; and that (3) in both cases the reverse reactions are very slow.

Colorimetric determination of reactive solid-supported primary and secondary amino groups

A simple and sensitive method for the quantitative determination of solid-supported primary and/or secondary amino groups using commercially available reagents is described. The solid supports are treated in an aqueous environment with either 2-iminothiolane (ITL) or sulpho-succinimidyl-3-(4-hydroxyphenyl) propionate (sulpho-SHPP), which introduce one sulphydryl or one hydroxyphenyl group per amino group reacted, respectively. These groups are capable of reducing Cu 2+ to Cu + in alkaline medium. Thus, after removal of the excess reagents through washing, subsequent incubation of the solids with 2,2′-bicinchoninic acid (BCA) copper protein reagent results in production of Cu + in the solution, which forms a chelate complex with BCA absorbing at 562 nm. The quantitation of the groups introduced on the surfaces, and therefore of the reacted amino groups, is carried out through standard curves of cysteine solutions for ITL, or tyrosine solutions for sulpho-SHPP-treated solids. Using ITL, only the primary amino groups are determined, whereas sulpho-SHPP provided the primary and secondary reactive amino groups. The method is versatile and can be used for the estimation of amino groups onto several biomedical solid matrices, and should provide useful information for the covalent immobilization of ligands (e.g. drugs, antibodies).