Showing papers on "Xanthene published in 1987"

Xanthene dyes having a fused (C) benzo ring

Abstract: Synthesis and applications of fluorescent dyes which are derivatives of benzo[c]xanthenes is described. The dyes exhibit pH dependent absorption and fluorescence spectra with pKas near the normal physiological range. Unlike fluorescein, the dyes exhibit emission of different characteristic wavelengths dependent on the pH of the medium. This permits several methods of measuring the pH of the medium in contact with the indicator including measuring two emissions with one excitation, selectively exiting the acid and base forms independently and measuring their emission at either single or dual wavelengths, or measuring the characteristic pH dependent absorption or fluorescence excitation spectral. Methods are presented for making the indicators permeant to cell membranes for the measurement of intracellular pH.

The Mechanism of Electron Transfer Reaction for Xanthene Dye-Sensitized Formation of Methyl Viologen Radical

Abstract: Sensitized reduction of methyl viologen, MV2+, occurs efficiently through electron transfer from triplet xanthene dyes to MV2+ followed by electron transfer to the resulting semioxidized dyes from ...

Photochemical primary process of xanthene dyes. 7. Xanthene dyes as probes for the characterization of anionic micelles

Abstract: The cationic xanthene dyes thiopyronine and selenopyronine are solubilized in the Stern regions of anionic micelles. Upon photoexcitation, the excited triplet states of the dyes are observed to decay via unimolecular processes ( k , z 2 X lo3 s-l) for the case of one dye per micelle and via bimolecular processes (k2 5 X lo6 S I ) for the case of more than one dye per micelle. If the number of dye triplet states that undergo slow decay is measured, the number of micelles can be obtained and thus the micellar aggregation numbers can be evaluated. The aggregation numbers of several surfactant alkanesulfonates, 2,5-dialkylbenzenesulfonates with a total of 14 carbon atoms in the alkyl chains, and other detergents, which are determined in this manner, are in agreement with corresponding values determined by using other photophysical methods and with literature values. The aggregation numbers of the dialkylbenzenesulfonate surfactants increase from 38 to 56 with increasing effective chain length. The fluorescence lifetime and fluorescence depolarization of thiopyronine solubilized in the dialkylbenzenesulfonate micelles are consistent with a low local polarity and high local viscosity for the interior of these micelles, compared to micelles of aliphatic detergents. Investigations using sodium 1 l-(3-hexyl1 -indolyl)undecyl sulfate (6-In-1 1) as a fluorescence probe suggest that the polarity of the interior of the dialkylbenzenesulfonate micelles is similar to that of liquid hydrocarbons. These results suggest a compact structure for the dialkylbenzenesulfonate micelles with low water penetration into the micelles.

Reactive dyes comprising a reactive radical bonded to the chromophor by a urea bridge member

Abstract: Reactive dyes of the formula ##STR1## in which D is the radical of an organic dye of the monoazo, polyazo, metal complex azo, anthraquinone, phthalocyanine, formazan, azomethine, dioxazine, phenazine, stilbene, triphenylmethane, xanthene, thioxanthone, nitroaryl, naphthoquinone, pyrenequinone or perylenetetracarbimide series, R is hydrogen or substituted or unsubstituted C1-4 -alkyl, A is a polymethylene radical having 2 to 6 C atoms (or its branched isomers) which can be substituted by chlorine, bromine, fluorine, hydroxyl, sulfato, acyloxy having 1 to 4 C atoms, cyano, carboxyl, alkoxycarbonyl having 1 to 5 C atoms or carbamoyl, or an alkyleneoxalkylene radical having 1 to 6 C atoms in each alkylene member, independently of each other; Y is a radical --CH═CH2 or --CH2 CH2 --Z, Z is an inorganic or organic radical detachable under alkaline conditions, B is hydrogen or the radical of a substituted or unsubstituted hydrocarbon, and n is 1 or 2, are suitable for dyeing or printing cellulose-containing and nitrogen-containing materials and in a high dyeing yield produce dyeings and prints of good fastness properties.

Triazinyl reactive dyestuffs in which triazinyl group is further substituted with a beta-chloroethylsulfonyl- or vinylsulfonylbutyrylamino moiety

Abstract: Reactive dyes of the formula ##STR1## in which D is the radical of an organic dye of the monoazo, polyazo, metal complex azo, anthraquinone, phthalocyanine, formazan, azomethine, dioxazine, phenazine, stilbene, triphenylmethane, xanthene, thioxanthrone, nitroaryl, naphthoquinone, pyrenequinone or perylenetetracarbimide series, R is hydrogen or substituted or unsubstituted C 1-4 -alkyl, X is a substituent which is detachable as an anion, B is a radical of the formula ##STR2## R 1 and R 2 , independently of each other, are hydrogen or substituted or unsubstituted C 1-4 -alkyl or phenyl, A is a substituted or unsubstituted aliphatic or aromatic bridge member, Y is a --CO--Z or --SO 2 --Z radical, Z is an aliphatic, aromatic or heterocyclic reactive radical, and n is 1 or 2, are suitable for dyeing or printing cellulose-containing and nitrogen-containing materials and in high dyeing yield produce dyeings and prints having good fastness properties.

Color electrophotographic toner

Abstract: PURPOSE:To give sharp magenta color and to enhance lightfastness resistant to discoloration due to light by incorporating a specified pigment as a colorant. CONSTITUTION:A combination of a quinacridone type pigment and a xanthene type dye or a pigment obtained by chelating xanthene type dye is incorporated in a toner as the colorant. The quinacridone type pigment, such as CI Pigment.Violet 19, CI Pigment.Red 122, or CI Pigment.Red 207, is used, preferably, in an amount of 0.2-20pts.wt., especially, 0.5-10pts.wt. based on 100pts.wt. the binder resin. The xanthene type dye, such as CI Solvent.Red 49, 52, or 108, is used, preferably, in an amount of 0.2-20pts.wt., especially, 0.5-10pts.wt. based on 100pts.wt. the binder.

Application of Xanthene Derivatives in Analytical Chemistry Part LXV. The Spectrophotometric Determination of Vanadium with O-Hydroxyhydroquinonephthalein in the Presence of Cationic Surfactants

Abstract: The colour reaction between o-hydroxyhydroquinonephthalein and vanadate ion in the presence of hexadecyltri-methylammonium chloride and L-ascorbic acid as a reductant was discussed. And the spectrophotometric determination of vanadium utilizing the colour reaction system in micellar media was proposed at about pH 5.4. Beer's law was obeyed in the concentration range 0-8 μg of vanadium at 540 nm. The apparent molar extinction was 8.7 × 10 4 1 mol−1 cm−1 with Sandell sensitivity of 0.0006 μg/cm2. This proposed method was relatively simple and sensitive, and then its applications for the waste water, river water, rain water, etc. were discussed.

New efficient dyes for the red part of the lasing spectrum

Abstract: An investigation was made of the spectral, fluorescence, and lasing characteristics of two compounds of benzopyran derivatives with a condensed benzimidazole ring that emit in the 610–660 nm range under flashlamp excitation. The efficiency and photostability of the synthesized derivatives were several times better than those of the known xanthene dyes rhodamine C and rhodamine 101. Quantum chemical calculations using the π electron approximation were used to estimate the localization of the electronic excitations in molecular fragments.

Spirolactones of Xanthene. IV. New Method of Xanthone Synthesis by Oxidation of Novel Spirolactones of Dibenzo [c, h] xanthene and Xanthenes

Abstract: Dibenzo [c, h] xanthone and halogen-and methyl-substituted xanthones have been synthesized by the oxidation of novel spirolactones of dibenzo [c, h] xanthene and xanthene, which were prepared by a new condensation reaction of 1-naphthol or phenol derivatives with oxalic acid in the presence of sulfuric acid. The oxidation was carried out by using potassium permanganate in the presence of aqueous potassium hydroxide. The dibenzo [c, h] xanthone and xanthones were identical with samples obtained by another synthetic route.

Image forming composition

Abstract: PURPOSE:To obtain an image forming composition developing yellow by oxidation and usable as a material for a PS plate, a photoresist, a proofing material or the like by adding a specified xanthene compound developing color by oxidation to an image forming composition. CONSTITUTION:A xanthene compound developing color by oxidation and represented by the formula is added to an image forming composition. In the formula, R1 is 1-8C alkyl or aralkyl, R2 is 1-8C alkoxy, lower alkyl, phenoxy, aralkoxy or optionally substituted amino, the substituent is alkyl, aryl or aralkyl, each of X, Y and Z is halogen, n, m and l are the numbers of X, Y and Z substituted on the aromatic rings, respectively, each of n and m is an integer of 0-2 and l is an integer of 0-4. The resulting image forming composition consists of the xanthene compound, a photooxidizing agent, an auxiliary coupler and a binder or further contains a fixing agent as required.

Purification of n,n-diethylaminophenol

Abstract: PURPOSE:To obtain, without any trouble in high yield, the high-purity compound which is used as an intermediate of heat-sensitive, pressure-sensitive dyes, xanthene dyes or fluorescent dyes, by purifying crude N,N-diethylaminophenol under specific conditions. CONSTITUTION:Reductive alkylation of an aminophenol with acetaldehyde is effected in the presence of a catalyst such as Pt, Pd in a solvent such as methanol, at room temperature to 150 deg.C under pressure with hydrogen to give N,N-diethylaminophenol. Then, in an inert gas (N, Ar) atmosphere, the product is brought into contact with solvents such as water or hexane over 50 deg.C and cooled down to give purified N,N-diethylaminophenol. The process according to the present invention solves the problems such as corrosion of the materials, excessive waste water and the quality of the product.

Photochemical Behaviour of Luminescent Dyes in Sol-Gel and Boric Acid Glasses

Abstract: Fluorescence of organic colorants is generally enhanced by high viscosity of the surrounding medium, having much fewer energetic collisions with the excited state, and perhaps also preventing large distortions along unsymmetrical vibrational modes. However, this is not simply determined by the macroscopic viscosity (Lewis and Calvin 1939) since cool glycerol is much more effective than a lubricating oil at the same low temperature. We are here studying fluorescein, belonging to the category of xanthene dyes (the heterocyclic xanthene is two benzene rings connected with two bridges in ortho-position, one being an oxygen atom and the other CH2) like the various substituted eosine and rhodamine modifications. In many cases, their quantum yield η is above 0.9, and corresponding to their very strong absorption bands in the visible, the life-time τ of fluorescein is only 4 nanoseconds in water and alcohols (Martin 1975).

Production of n,n-dialkylaminophenol

Abstract: PURPOSE:To obtain a compound useful as a synthetic intermediate for heat- and pressure-sensitive paper, xanthene dyes, etc., in high selectivity without problems in material corrosion, by reacting an aminophenol with an aldehyde under specific condition. CONSTITUTION:An aminophenol is reacted with an aldehyde expressed by the formula R.CHO (R is 1-5C alkyl) in the presence of a platinum or/and catalyst supported on active carbon carrier in a solvent, e.g. aliphatic alcohol, under 2-30kg/cm G pressure of hydrogen at 0-80 deg.C to afford the aimed substance. In the process, the molar ratio of the aminophenol to the aldehyde is >=1.5-<4 and the aldehyde is continuously introduced into the reaction system at <=0.1mol/ min introduction rate based on 1mol aminophenol to carry out the reaction.

The chemistry of the insoluble red woods. XVIII: The X-ray structure of 9-methoxy-6-(4-methoxybenzyl)-5-(4-methoxyphenyl)benzo[a]xanthene

Abstract: Le compose C 33 H 28 O 4 cristallise dans le systeme monoclinique, groupe P2 1 /n et sa structure est affinee jusqu'a R=0,043

Production of n-monoalkylaminophenol

Abstract: PURPOSE:To suppress formation of by-products and obtain a compound useful as a synthetic intermediate for dyes used in heat- and pressure-sensitive paper, xanthene dyes, etc., in high selectivity without problems in material corrosion, by reacting an aminophenol with an aldehyde under specific condition. CONSTITUTION:An aminophenol is reacted with an aldehyde expressed by the formula RCHO (R is 1-5C alkyl) in the presence of a platinum or/and palladium catalyst supported on active carbon carrier in a solvent, e.g. methanol, etc., under 2-30kg/cm G pressure of hydrogen at 0-80 deg.C to afford the aimed substance expressed by the formula. In the process, the molar ratio of the aldehyde to the aminophenol is >=0.8-<1.5 and the aldehyde is continuously introduced into the reaction system at <=0.1mol/min introduction rate based on 1mol aminophenol to carry out the reaction.

Production of n,n-dialkyl substituted aminophenol

Abstract: PURPOSE:To obtain a compound useful as a synthetic intermediate for dyes in heat- and pressure-sensitive paper, xanthene based dyes, fluorescent dyes, etc., by subjecting an aminophenol and aldehyde to N-alkylating reaction under specific condition and further reacting the resultant product with an aldehyde. CONSTITUTION:One mol aminophenol is reacted with 0.8-1.5mol aldehyde, expressed by the formula R.CHO (R is 1-5C alkyl) in the presence of a catalyst, e.g. platinum supported on active carbon and/or Pd, in an aliphatic alcoholic solvent at 0-80 deg.C under pressure of hydrogen to give an N-monoalkyl- substituted aminophenol expressed by formula I, which is subsequently reacted with 0.8-2.5mol aldehyde expressed by the formula R'.CHO (R' is 1-5C alkyl) to afford the aimed substance expressed by formula II. The aldehyde is introduced into the reaction system at <=0.1mol/min rate based on 1mol aminophenol and/or compound expressed by formula I. EFFECT:Side reaction is suppressed and the aimed substance is obtained in high selectivity without any problem in corrosion of materials.

Penicillium auxotrophic mutants can be detected by suing xanthene dyes

Abstract: Auxotrophic mutants ofPenicillium spp. have been directly isolated after mutagenic treatment from agar plates containing Xanthene dyes. They grow as characteristic small colored colonies. Some strains were tested and they showed a differential response depending on the Xanthene dye used.

Reactive dyes, process for their preparation and their use in the dyeing and printing of substrates

Abstract: of EP01256501. Reactive dyestuffs of the formula see diagramm : EP0125650,P52,F4 wherein D is the radical of an organic dyestuff of the mono- or poly-azo, metal complexazo, phthalocyanine, formazan, azomethine, dioxazine, phenazine, stilbene, triphenylmethane, xanthene, thioxanthone or nitroaryl series, W is a direct bond or a bridge member, R is hydrogen or alkyl, A is a radical of the formula see diagramm : EP0125650,P52,F7 wherein X = hydrogen or chlorine and Z = CCl3 , CHCl2 or CH2 Cl, and n is 1 or 2.

Synthesis of New Xanthene Derivatives with Expected Antischistosomal Activity.

Abstract: N-(9H-Xanthen-9-yl)succinimide (1) is prepared by the reaction of xanthene with N-bromosuccinimide. Hydrolysis of 1 with 5% NaOH yields 3-[(9H-xanthen-9-yl)aminocarbonyl]propionic acid (3a). The corresponding methyl ester 3c is obtained from 3a by the action of diazomethane. The butanol derivative 4a can be obtained by reduction of 3a or 3c with LiAlH4. Treatment of 1 with LiAlH4 yields the pyrrolidine derivative 5. N-(9H-Xanthen-9-yl)phthalimide (2) undergoes similar reactions like its analogue 1.