Anthraquinone Carboxylic Acid Research Articles

Separation of 9,10-anthraquinone derivatives: Evaluation of functionalised stationary phases in reversed phase mode

A series of reversed phases bonded with several functional groups was investigated for separation of anthraquinone derivatives, following the previous work, dedicated to the selectivity of octadecyl silica bonded phases. Considering wide diversity of substitutions in hydrophobic anthraquinone skeleton, interactions like dipole–dipole, π–π or H-bond acceptor/donor, as well as inclusion complexes formation can be employed to improve separation. In this study, several phases with grafts like cyano, nitro, aromatic, PEG, diol, calixarene and cyclodextrin were used with water–acetonitrile gradient for separation of thirty anthraquinoids’ standards. The evaluation of performances was measured using the symmetry parameter and the number of critical pairs of peaks formed. The results point out the aromatic and calixarene bonded silica as the most interesting in terms of symmetry and critical pairs number. Finally we tested the performance of Caltrex Resorcinaren, Pursuit XRs DP and Luna Phenyl-Hexyl on real samples of anthraquinone natural dye extracted from a red thread taken from a 15th C. tapestry. We observed and compared the retention behaviour of some new anthraquinoids additional to our standards set and showing behaviour particular to substituted anthraquinone carboxylic acids.

Clamping down on weak terminal base pairs: oligonucleotides with molecular caps as fidelity-enhancing elements at the 5'- and 3'-terminal residues.

The base-pairing fidelity of oligonucleotides depends on the identity of the nucleobases involved and the position of matched or mismatched base pairs in the duplex. Nucleobases forming weak base pairs, as well as a terminal position favor mispairing. We have searched for 5'-appended acylamido caps that enhance the stability and base-pairing fidelity of oligonucleotides with a 5'-terminal 2'-deoxyadenosine residue using combinatorial synthesis and MALDI-monitored nuclease selections. This provided the residue of 4-(pyren-1-yl)butyric acid as a lead. Lead optimization gave (S)-N-(pyren-1-ylmethyl)pyrrolidine-3-phosphate as a cap that increases duplex stability and base-pairing fidelity. For the duplex of 5'-AGGTTGAC-3' with its fully complementary target, this cap gives an increase in the UV melting point T(m) of +10.9 degrees C. The T(m) is 6.3-8.3 degrees C lower when a mismatched nucleobase faces the 5'-terminal dA residue. The optimized cap can be introduced via automated DNA synthesis. It was combined with an anthraquinone carboxylic acid residue as a cap for the 3'-terminal residue. A doubly capped dodecamer thus prepared gives a melting point decrease for double-terminal mismatches that is 5.7-5.9 degrees C greater than that for the unmodified control duplex.

Dermorubin and 5-Chlorodermorubin Natural Anthraquinone Carboxylic Acids as Dyes for Wool

Wool is dyed for the first time with a mixture of two pure natural anthraquinone carboxylic acids, dermorubin and 5-chlorodermorubin (2:1), by means of the acid dyeing technique. The anthraquinone carboxylic acids are isolated from the fungus Dermocybe sanguinea and separated by multiplicative liquid-liquid partition using a stepwise pH gradient. The color of the dyed wool is investigated in terms of the CIELAB L*, a*, and b* parameters, and color-fastnesses to light, washing, and rubbing are tested according to ISO standards. The mixture of dermorubin and 5-chlorodermorubin dyes wool orange-red with good color-fastness properties. Our procedure is equivalent to the industrial winch- technique. The results indicate that wool has a high uptake for the anthraquinone carboxylic acids. Apparently, the ionic bonds between the carboxylate ions of the dye and the protonated amino groups of the wool enhance the color-fastness properties of the dyed fabric. Dermorubin and 5-chlorodermorubin have significant potential as textile dyes. affording useful alternatives to synthetic dyes.

TCF BLEACHED PULPS FROM MISCANTHUS SINENSIS BY THE IMPREGNATION RAPID STEAM PULPING (IRSP) PROCESS

ABSTRACT The production of bleached cellulose pulps from elephant grass (Miscanthus sinensis) via a two-stage soda pulping process and a TCF bleaching sequence is evaluated in this work. The impregnation rapid steam pulping process (IRSP) involves impregnating of the lignocellulosic material with the pulping liquor, withdrawing the excess liquor and rapidly steaming the impregnated material at 180–200°C for a short time. In this paper the process variables and their effect on the kappa number, yield and viscosity of the unbleached pulps are discussed. Bleaching by an ozone-based TCF sequence was tested, and the papermaking properties of the bleached pulp were determined. A kappa number of 19 was obtained by impregnating at an alkali charge of 30 + 0.1% anthraquinone carboxylic acid (AQCA) and pulping at 180°C for only 15 min. Kappa was reduced to 16 by extending pulping time to 26 min. The alkali consumption during impregnation and pulping was 10.2 g NaOH/100 g of dry Miscanthus. Screened pulp yield, viscosity and brightness for this pulp were 54.6%, 913 mL/g and 37.3%, respectively. After bleaching, the pulp had an ISO brightness of 87.4% and a viscosity of 700 mL/g. Refining in a PFI mill provided optimal strength properties of the bleached pulp at 4500 revolutions (71°SR): breaking length 7.2 km, tensile index 72 N m/g, and burst index 4.3 kN/g. Tear index was 7.9 mN m2/g at this degree of refining.

Stepwise pH-gradient elution for the preparative separation of natural anthraquinones by multiple liquid-liquid partition.

Preparative-scale separation of substituted anthraquinones by multiple liquid-liquid partition was studied using isopropylmethyl ketone (IMK)/aqueous phosphate buffer (aq.) as the solvent system and the Hietala apparatus with 100 partition units as the partition equipment. The lower (aq.) phase was chosen as mobile, while the upper (IMK) phase remained stationary. Hence, the principle of stepwise pH-gradient elution could be utilized to separate the components in two complex mixtures of hydroxyanthraquinones and hydroxyanthraquinone carboxylic acids, isolated from the fungus Dermocybe sanguinea. In spite of the nonlinearity of the partition isotherms for these anthraquinones, implying deviations from the Nernst partition law, remarkable separations were achieved for the components in each mixture. Every anthraquinone carboxylic acid showed markedly irregular partition behavior, appearing in the effluent as two more or less resolved concentration zones. Such splitting was attributed to the formation of relatively stable sandwich-dimers, which were in a slow equilibrium with the monomers in the more nonpolar organic phase. At lower pH-values, only the polar monomers were distributed into the mobile aqueous phase and moved forward, whereas the nonpolar sandwich-dimers remained almost entirely in the stationary organic phase and lagged behind. When the pH of the mobile aqueous phase was raised high enough, the firmly linked dimers were monomerized and emerged from the apparatus as a second concentration profile. Intermolecular hydrogen bonding and pi-pi interaction between the pi-systems of two anthraquinone molecules in a parallel orientation were considered responsible for the nonlinear and markedly irregular partition behavior of the natural anthraquinones studied. The nonlinearity of the partition behavior of the hydroxyanthraquinones lacking the carboxyl group, appeared merely as excessive broadening of the experimental concentration profile, which impaired the resolution between the components only insignificantly. Thus, e.g. the main components, dermocybin and emodin, could both be obtained from Separation 1 in a purity of at least 99%.

Synthesis and monitored selection of nucleotide surrogates for binding T:A base pairs in homopurine-homopyrimidine DNA triple helices.

A total of 16 oligodeoxyribonucleotides of general sequence 5'-TCTTCTZTCTTTCT-3', where Z denotes an N-acyl-N-(2-hydroxyethyl)glycine residue, were prepared via solid phase synthesis. The ability of these oligonucleotides to form triplexes with the duplex 5'-AGAAGATAGAAAGA-HEG-TCTTTCTATCTTCT-3', where HEG is a hexaethylene glycol linker, was tested. In these triplexes, an 'interrupting' T:A base pair faces the Z residue in the third strand. Among the acyl moieties of Z tested, an anthraquinone carboxylic acid residue linked via a glycinyl group gave the most stable triplex, whose UV melting point was 8.4 degrees C higher than that of the triplex with 5'-TCTTCTGTCTTTCT-3' as the third strand. The results from exploratory nuclease selection experiments suggest that a combinatorial search for strands capable of recognizing mixed sequences by triple helix formation is feasible.

Preparative Isolation of Anthraquinones from the Fungus Dermocybe sanguined Using Enzymatic Hydrolysis by the Endogenous β-Glucosidase

Abstract A new and simple enzymatic method was developed for preparative isolation of anthraquinone pigments from Dermocybe sanguined. The endogenous β-glucosidase of the fungus was used to catalyze the hydrolysis of the O-glycosyl linkage in emodin- and dermocybin-1-β-ᴅ-glucopyranosides. The developed enzymatic method was found to be effective for the pigment isolation, as the hydrolysis occurred virtually completely, thus leading to a high pigment yield. Two fractions were obtained by the method: Fraction 1 (94% of the total pigment amount), containing almost exclusively the main pigments emodin and dermocybin, and Fraction 2 (6% ), containing the anthraquinone carboxylic acids. A 10.5 kg amount of fresh fungi yielded 56 g of Fraction 1 and 3.3 g of Fraction 2 anthraquinones. The anthraquinones in each fraction were separated by thin-layer chromatography using toluene-ethyl acetateethanol- formic acid (10:8:1:2, v/v/v/v) as eluent. The components on the chromatograms were detected and characterized by measurements on a densitometer-spectrophotometer. Combined gas chromatography-mass spectrometry was applied to determine the anthraquinone derivatives of Fraction 1 after methylation and acetylation.

ChemInform Abstract: Heck Reaction: Stereoselective Synthesis of Trisubstituted Olefins: Useful Intermediates for Anthraquinone Carboxylic Acid Derivatives.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Heck Reaction: Stereo Selective Synthesis of Trisubstituted Olefins: Useful Intermediates for Anthraquinone Carboxylic Acid Derivatives

Palladium catalyzed arylation of dialkyl itaconate in presence of Pd(OAc)2/PPh3 as a catalyst, afforded trisubstituted olefins stereo selectively. These alkenes are useful intermediates for the synthesis of anthraquinone carboxylic acid derivatives. A new coumarin is also synthesized using this protocol.

ChemInform Abstract: Pigments of Fungi. Part 47. Cardinalic Acid, a New Anthraquinone Carboxylic Acid from the New Zealand Toadstool Dermocybe cardinalis and the Synthesis and X‐Ray Crystal Structure of Methyl 1,7,8‐Tri‐O‐methylcardinalate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Pigments of Fungi. XLVII. Cardinalic Acid, a New Anthraquinone Carboxylic Acid from the New Zealand Toadstool Dermocybe cardinalis and the Synthesis and X-Ray Crystal Structure of Methyl 1,7,8-Tri-O-methylcardinalate

Cardinalic acid (1,7,8-trihydroxy-6-methoxy-3-methyl-9,10-dioxoanthracene-2-carboxylic acid) (4) and the known anthraquinone carboxylic acids endocrocin (1), dermolutein (2) and cinnalutein (3) have been isolated from the New Zealand toadstool Dermocybe cardinalis. Methyl 1,7,8-tri-O-methylcardinalate (5) has been prepared both by permethylation of the natural product (4) and from 2,6-dichloro-1,4-benzoquinone by two consecutive regioselective Diels–Alder cycloaddition reactions. A single-crystal X-ray structure analysis of the ester (5) corroborates the structure of the natural product (4) and confirms the outcome of both cycloaddition reactions.

Synthesis, bioactivity, and DNA-cleaving ability of desferrioxamine B-nalidixic acid and anthraquinone carboxylic acid conjugates

Synthesis and in vitro activity of two novel conjugates ( 4 and 5) of desferrioxamine B, with nalidixic acid ( 2) and anthraquinone carboxylic acid ( 3), are described.

Precursors to aromatic units in coal

Previous oxidation experiments with bituminous coal have produced fluorenone, benzophenone and anthraquinone carboxylic acids. Precursors to these acids were speculated to be fluorene, diphenylmethane, anthracene and 9,10-dihydroanthracene derivatives. Oxidation experiments suggested that polymethylene bridges between aromatic units may also act as precursors to these acids.

Neue Anthrachinonfarbstoffe aus Cortinarius armillatus und C. miniatopus (Agaricales) [1] / New Anthraquinone Pigments from Cortinarius armillatus and C. miniatopus (Agaricales) [1

Acids A reinvestigation of the velum pigments of Cortinarius armillatus yielded the new anthraquinonecarboxylic acids endocrocin-6,8-dimethyl ether (4) and dermorubin-6-methyl ether (8).

Structure and biosynthesis of the ergot pigments.

AbstractIn addition to the well known alkaloids, ergot contains two groups of yellow to red pigments, between which there is a close and novel biogenetic relation. The pigments are anthraquinonecarboxylic acids and dimeric hydroxanthone derivatives (ergochromes), the structures of which, including the absolute configurations at 80 centers of chirality, have been completely determined. The intermediates involved in the biosynthesis have been largely established by feeding with labeled precursors, and its course by model experiments.

Studies in the Anthraquinone Series. Attempts to synthesise Anthraquinone Carboxylic Acids of the Morindone Type.

Studies in the Anthraquinone Series. Attempts to synthesise Anthraquinone Carboxylic Acids of the Morindone Type.