Xanthene

About: Xanthene is a research topic. Over the lifetime, 2132 publications have been published within this topic receiving 34803 citations. The topic is also known as: Xanthene & dibenzo[a,e]pyran.

Anionic water insol. dyes, easily dispersible in cold water - in the form of a salt of a cationic water soluble condensn. prod. of a guanidinium salt and formaldehyde

Abstract: Anionic water-insoluble dyes which are easily dispersed in cold water, are at least partially in the form of a salt of a water soluble cationic resin comprising a condensn prod of formaldehyde with a guanidinium salt The resins are made by condensing 05-5 moles, esp 08-2 moles formaldehyde with 1 mole of guanidine salt in an aq medium at 50-90 deg C and a pH of 4-12, esp 7-10 Generally the dye salt is composed of 01-3 moles guanidine per molar equiv anionic dye, esp 1 mole guanidine condensed with 1 mole formaldehyde per molar equiv anionic dye The dyes used are eg those contg sulphonic, phosphonic or carboxylic acid gps, and may be eg of the phthalocyanine, nitro, di- or triphenylmethane, oxazine, thiazine, dioxazine, xanthene, or (esp) anthraquinone or azo series The dyes disperse easily in cold water in the formation of dye baths or printing pastes which have no tendency to recrystallisation, gelling or reagglomeration The dyes are esp useful for colouring natural or synthetic polyamides and/or cellulosic fibres

Adsorption mechanism for xanthene dyes to cellulose granules.

Abstract: The xanthene dyes, erythrosine, phloxine, and rose bengal, were adsorbed to charred cellulose granules The charred cellulose granules were preliminarily steeped in ionic (NaOH, NaCl, KOH, KCl, and sodium dodecyl sulfate (SDS)), nonionic (glucose, sucrose, and ethanol), and amphipathic sucrose fatty acid ester (SFAE) solutions, and adsorption tests on the dye to the steeped and charred cellulose granules were conducted Almost none of the dye was adsorbed when the solutions of ionic and amphipathic molecules were used, but were adsorbed in the case of steeping in the nonionic molecule solutions Thin-layer chromatography (TLC) and the Fourier transform infra-red (FT-IR) profiles of SFAE which was adsorbed to the charred cellulose granules and extracted by ethyl ether suggested the presence of hydrophobic sites on the surface of the charred cellulose granules We confirmed that the xanthene dyes could bind to the charred cellulose granules by ionic and hydrophobic bonds

Multi-Dye Photosensitization System of Xanthene Iodonium Salts.

Abstract: We have synthesised the serries of xanthene dye iodouium (XT On, including FL, FC, FI, EO, ER and RB) and studied their spectral properities and photochemical behavior. Under irradiation of visible light, the electron transfer reaction which occured between xanthenic moiety and oaium caused the photolysis of onium to generate active radical, simultaneousty, xanthene dye occured photobleaching reaction. The results of spectral kinetic studies indicate that their photobleaching rate is in the order of FL>FC>FI>EO>ER>RB. At the same time, we have also studied the role of energy transfer sensitization among different xanthene dyes, and depended on this method to speed up the photobleaching reaction. In photochemical reaction system of multi-xanthene iodonium, the rate of electron transfer process is higher than the one of energy transfer process, so their photochemical reaction is equivalent to the one of each single component . On the basis of the result, different systems of multi-xanthene onium can be used in the certain ranges of wave length, for their spectral response covers most region of visible light from 440nm to 600nm. Application of the multi-dye photosensitization system can effectively improved the effecience of photopolymeization initiated radical.

Synthesis of novel hydroxyspiro[indoline-3,9′-xanthene]trione derivatives using solid acids as catalyst

Abstract: An eco-friendly method for the synthesis of hydroxyspiro[indoline-3,9′-xanthene]triones as new spiro[indoline-3,9′-xanthene]trione derivatives is described. These syntheses were accomplished via pseudo three-component condensation reaction of dimedone and isatin derivatives in the presence of silica-bonded n-propyltriethylenetetraminesulfamic acid in refluxing ethanol. Most of the acid catalysts gave spiro[indoline-3,9′-xanthene]triones as the final products. In the present method by using different amounts of acid catalyst and controlling the conditions, hydroxyspiro[indoline-3,9′-xanthene]triones were obtained as the only product. The advantages of our method are practical simplicity, using reusable heterogeneous catalyst, short reaction times, and good yields of the products. The recycled catalyst could be reused fifth times without appreciable loss in the catalytic activity. Two compounds were found to display in vitro antioxidant and cholinesterase inhibitory activities.

Rearrangement Reactions for the Synthesis of Some Oxa- and Aza-tricyclic Rings Heterocyclic Compounds

Abstract: This review article describes the main results of our research during the last 5-6 years. A series of new rearrangement reactions was discovered and used for the synthesis of novel heterocyclic compounds: furo[2,3-f]isoquinolines, furo[3,2 -f] quinolines, benzo[c]xanthene, benzo[h]chromene, benzo[a]xanthene, benzo[f]chromene, furo[2,3-f]isoquinoline, spirofuro[3,2-f]quinoline, cycloalkanoindoles, and benzotriazines.