Reaction Of Phloroglucinol Research Articles

Qualitative analysis and HPLC isolation and identification of procyanidins from Vicia faba.

The soluble proanthocyanidins of the coloured seed coats of Vicia faba L. were isolated and separated by solvent partition. The chemical characteristics of the proanthocyanidins were elucidated by total oxidation and partial degradation in the presence of phloroglucinol followed by HPLC analysis. The native extract of proanthocyanidins contained (+)-gallocatechin, (-)-epigallocatechin, (+)-catechin and (-)-epicatechin units. Oligomeric procyanidins were purified by chromatography on Sephadex LH-20 and the accessible compounds were isolated by RP-HPLC using a Licrospher Li 100 Column. The structures of the purified oligomeric procyanidins were elucidated using a procedure involving TLC, UV spectroscopy, ESI-MS and HPLC analysis of the products from the phloroglucinol reaction. The major condensed tannins of Vicia faba comprise six compounds identified as two A-type procyanidin dimers, the procyanidin dimers B1, B2 and B3, and a procyanidin trimer.

A study on the selective phosphorylation and phosphinylation of hydroxyphenols

AbstractBy choice of appropriate reaction conditions, the phosphorylation of hydroquinone by diethyl chlorophosphate gave predominantly the monophosphate (2). A similar reaction of phloroglucinol led to the mixture of the possible products (6, 7, and 8). The monophosphinylation of the above hydroxyphenols by diphenylphosphinyl chloride could be accomplished with a good selectivity to give product 4 or 9, the yields, however, being variable. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:126–130, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10006

The action of phloroglucinol in the presence of hydrochloric acid on photoaged, totally-chlorine-free, bleached chemical pulps

UV-Vis diffuse reflectance spectrometry has been used to monitor the reaction of phloroglucinol (in the presence of hydrochloric acid) with totally-chlorine-free (TCF) bleached softwood bisulfite chemical pulps. Pulps (1–4) bleached via various sequences, which include ozone and hydrogen peroxide processes, were studied. The unirradiated pulps show a very small absorption band with a maximum at about 460 nm when the phloroglucinol test was performed. Pulp 3, which was bleached only with peroxide and contains the higher amount of lignin (Kappa number, 4), displays, after ageing with UV light and after the phloroglucinol test, a broad absorption band with a maximum at 560 nm, similar in behaviour to photodiscoloured lignin-rich pulps. Pulp 2, bleached by one ozone stage followed by a peroxide stage (Kappa number, 1.7) displays the same trend (broad band centred at 560 nm) although the lignin content was lower. This indicates that the phloroglucinol test is very sensitive to oxidized lignin. Pulps 1 and 4, which were fully bleached (Kappa number, 0.5 or less), still present a narrow absorption band around 555 nm after irradiation with UV light. The origin of this band remains uncertain. ortho-Quinone models adsorbed on cellulose paper appear to be insensitive to the phloroglucinol test, in contrast to 2-methoxy- para-quinone and coniferaldehyde. Such chromophores are probably formed by UV irradiation of the TCF pulps.

The reaction of phloroglucinol in the presence of acid with lignin-containing materials

UV-visible diffuse reflectance spectrometry has been used to monitor the reaction of phloroglucinol (in the presence of hydrochloric acid) with high yield pulps. When papers made from such pulps are irradiated, coniferaldehyde residues are generated as judged by their reaction with phloroglucinol/HCl. Treatment of such papers with sodium borohydride reduces the coniferaldehyde residues and consequently no colour reaction with phloroglucinol/HCl is observed. Irradiation of these borohydride-reduced papers leads to the generation of coniferaldehyde entities as detected by phloroglucinol/HCl. Similar results were obtained using a thin section of abies wood. Irradiation of papers made from high yield pulps destroys coniferaldehyde residues on the one hand and generates them from other sources on the other hand. Examination of papers made from the morphological components of poplar showed that it is impossible to quantify the amount of lignin present by this colour test method. Thioacidolysis analysis of the fractions shows for all of them a higher proportion of syringyl than guaiacyl β-O-4 aryl ether linkages. In contrast, photocleavage of the β-O-4 aryl ether linkages is more important for the guaiacyl structures. This is in accordance with the observed higher sensitivity to UV light of softwood pulps compared with hardwood pulps. Also, the thioacidolysis experiments indicate that UV irradiation of the fractions maintains a stationary concentration of the coniferaldehyde structures.

Condensed Tannins: Reactions of Model Compounds with Furfuryl Alcohol and Furfuraldehyde

Abstract Reaction products of phloroglucinol or catechin with furfuryl alcohol and furfuraldehyde were studied. In reactions of furfuryl alcohol with phloroglucinol, only 2-furyl-1′,3′,5′-trihydroxyphenyl) methane was obtained as product, and 53% of the phloroglucinol was recovered. Reactions of furfuryl alcohol with catechin gave 2-furyl-(8-catechinyl) methane and 2-furyl-(6-catechinyl) methane in 4.0% and 1.5% yields, respectively, while 62% of the catechin was unreacted. Polymeric furans with few catechin moieties made up the oligomeric products (38% of catechin). Reaction of phloroglucinol with furfuraldehyde gave 2-furyl-di(1′,3′,5′-trihydroxyphenyl) methane, an unstable product that readily polymerized during isolation. The solid state 13C-NMR spectrum of the higher polymers suggested one phloroglucinol moiety per furan unit, but lower oligomers contained more furan-furan condensation products. Reactions of catechin with furfuraldehyde gave 2-furyl-di(8-cate-chinyl) methane and the two diastereomers...

Functional polymers, 32. 5‐Methoxy‐ and 5‐hydroxy‐2H‐benzotriazol‐2‐yl mono‐ or disubstituted resorcinols or phloroglucinols

AbstractFour new 5‐methoxy‐2H‐benzotriazol‐2‐yl mono‐ or di‐substituted resorcinols and phloroglucinols 5a, b and 6a, b were synthesized by reaction of resorcinol or phloroglucinol with 4‐methoxy‐2‐nitrobenzenediazonium chloride in a 1:1 or 1:2 mole ratio and subsequent reductive cyclization with zinc and sodium hydroxide. The methoxy groups of all four compounds were cleaved with dry hydrogen bromide gas in dimethylformamide leading to the corresponding hydroxyl derivatives 7a, b and 8a, b in nearly quantitative yields. Unlike the reaction of phloroglucinol with a large excess of 2‐nitrobenzenediazonium chloride, which gave the trisubstituted product, with 4‐methoxy‐2‐nitrobenzenediazonium chloride no phloroglucinol derivative with three 5‐methoxy‐2H‐benzotriazol‐2‐yl groups could be obtained. All the resulting products were characterized by their IR, 1H, and 13C NMR, and UV spectra. The resorcinol derivatives (both methoxy‐ and hydroxy‐) Showed λmax of 345 nm and an absorption coefficients as high as 4 · 104 l · mol–1 · cm−1, and the phloroglucinol derivatives a λmax of 350 nm and an absorption coefficient as high as 4,5 · 104 l · mol−1 · cm−1.

Metabolism of 2,4-dichlorophenoxyacetic acid in cell suspension cultures of soybean (Glycine max L.) and wheat (Triticum aestivum L.)

Cell suspension cultures of soybean (Glycine max L.) and wheat (Triticum aestivum L.) incorporated 2,4-dichlorophenoxyacetic acid (2,4-D) into a metabolite fraction which was insoluble in ethanol, water, and hot sodium dodecylsulphate. Further treatment with hot dimethylformamide solubilized a material which by the following criteria appeared to consist of 2,4-D derivatives covalently bound to lignin: i) co-chromatography of radioactivity and of UV-absorbing material upon gel permeation chromatography; ii) spectral similarity with authentic lignins (IR- and UV-spectra, phloroglucinol reaction), 2,4-D appeared to be incorporated as the intact molecule, as shown by comparison of ring- and sidechain-labeled 2,4-D and by detection of monohydroxylated and intact 2,4-D as the major radioactive products of acid hydrolysis. The same compounds were released from the metabolite material which could not be solubilized in dimethylformamide. The incorporation of xenobiotics or their metabolites into lignin, followed by deposition in the cell wall, is suggested as a general pathway for 'local excretion' and detoxification by plant cells.

Partial freezing as a means of preserving fish freshness. I. Changes in free amino acids, TMA-N, ATP and its related compounds, and nucleic acids during storage.

In order to develop a storage procedure to be used in place of iced or frozen storage for the preservation of fish freshness, partial freezing for periods of up to 2-3 weeks was examined using sea bass. The criteria for evaluation were made according to the changes in the amounts of free amino acids and trimethylamine nitrogen as well as post-mortem autodegradation of nucleotides and nucleic acids in fish muscle.The changes in the free amino acids of muscle during storage at -3°C differed significantly from those observed during ice storage, though no significant differences were observed between the muscles iced and stored at -2°C. During storage at -3°C, no appreciable amount of trimethylamine nitrogen was detected, initial spoilage of the fish being greatly reduced. The K value of fish muscle stored at -3°C reached 20% after 2 weeks, whereas that of iced muscle reached 58% in 5 days.The possibility that nucleic acids in fish muscle might be broken down to their mononucleotide constituents during ice storage or storage at -3°C was almost negligible as far as could be determined colorimetrically with the phloroglucinol reaction. However, degradation of nucleic acid molecules in iced muscle was indicated by the results of chromatography on methylated albumin kieselgur, whereas the degradation was reduced noticeably in muscle stored at -3°C.From the present results with sea bass, storage by partial freezing at -3°C seems to be effective as a means of preserving fish freshness when storage must be prolonged beyond the storage life of iced fish.

Condensation cyclization reactions of electron-deficient aromatics. IV. Tricyclic nitropropene nitronates from the reaction of phloroglucinol and cycloalkanones with sym-trinitrobenzene

Interesting similarities have been shown between the reactions of sym-trinitrobenzene with cycloalkanones, and with phloroglucinol. Previously unsuspected common intermediates have been shown to intervene. The structurally similar products in each case are tricyclic nitropropene nitronates. Protonation of these yields the corresponding nitronic acids in certain instances.

Reaction of phloroglucinol with sodium borohydride

Reaction of phloroglucinol with sodium borohydride

A new color reaction for the determination of aldopentose in presence of other saccharides

1. 1. A new modification of the phloroglucinol reaction of pentoses is described. 2. 2. The application of this reaction for the quantitative determination of aldopentoses in presence of other sugars is discussed.

The Reaction of Phloroglucinol with 1-Methyl-piperazine

The Reaction of Phloroglucinol with 1-Methyl-piperazine