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.

3′,6′‐Bis(diethylamino)‐2‐propylspiro[isoindoline‐1,9′‐xanthen]‐3‐one

Abstract: In the crystal structure of the title compound, C31H37N3O2, the dihedral angle between the planes of the xanthene ring system and the spiro­lactam ring is 90.3°.

New organosoluble poly(arylene ether nitrile) copolymers based on 9,9-bis(3,5-dimethyl-4-hydroxyphenyl)xanthene

Abstract: Several poly(arylene ether nitrile) (PAEN) copolymers containing multi-methyl and cardo xanthene groups were synthesized by nucleophilic substitution reaction of 2,6-difluorobenzonitrile with varying molar ratios of 9,9-bis(3,5-dimethyl-4-hydroxyphenyl)xanthene (BDMHPX) and hydroquinone (HQ) (80/20–40/60) in N-methyl-2-pyrrolidone (NMP) in the presence of anhydrous potassium carbonate. These new PAENs had inherent viscosities between 0.56 and 0.68 dL g–1, and their weight-average molecular weights and number-average molecular weights were in the range of 33,300–36,500 g mol−1 and 17,300–18,400 g mol−1, respectively. All polymers were amorphous and soluble in dipolar aprotic solvents such as NMP and N,N-dimethylacetamide and even in THF and chloroform at room temperature. These PAENs showed glass transition temperatures (Tgs) between 248°C and 289°C, and the Tg values were found to increase with increase of the BDMHPX content in the polymeric main. Thermogravimetric analysis showed that all PAENs were stab...

A Colour Reaction for Non-Ionic and Amphoteric Soaps

Abstract: THE ability of colloidal electrolytes to change the colour of oppositely charged dyes is well known. One of the earliest systematic studies was that of Hartley1, and later Harkins and others showed that the colour change could be used to observe micelle formation2. Similar colour changes can sometimes be caused by non-ionic soaps in solutions of ionized dyes of either charge, but a more striking effect is found with some non-ionic soaps and certain xanthene dyes in the undissociated form. Instead of the usual band shift of between 10 and 20 mµ to the red, there is a more or less complete removal of the main absorption band and discharge of visible colour. Discharge also occurs if water-miscible organic solvents are added, or if the dye is dissolved in the pure solvent.

Fe3O4@SiO2 nanoparticles: An efficient, green and magnetically reusable catalyst for the one-pot synthesis of 14-aryl-14H-dibenzo[a,i]xanthene-8,13-dione derivatives

Abstract: An efficient and eco-friendly method for the one-pot synthesis of 14-aryl-14H-dibenzo [a,i]xanthene-8,13-dione derivatives has been developed in the presence of Fe3O4@SiO2 core-shell nanoparticles. The multi-component reactions of 2-hydroxy-1,4naphthoquinone, β-naphthol and aldehydes were efficiently catalyzed using novel nano-scale materials under reflux conditions. The present method offers several advantages such as environmentally benign, simple work-up, excellent yield of products, short reaction times, little catalyst loading and facile catalyst separation. The nanomagnetic catalyst could be readily recovered using a simple external magnet and reused several times without any significant loss in activity. The catalyst was fully characterized by FT-IR, SEM, XRD, EDX and VSM analysis.

Diagnostic agents for positron emission imaging using radiolabeled halogenated xanthenes

Abstract: New diagnostic agents for positron emission tomography (PET) and methods for use of such agents for imaging of human or animal tissue are described, wherein a primary active component of such agents is a radiolabeled halogenated xanthene or halogenated xanthene derivative. Preferably, the radiolabeled halogenated xanthene is radiolabeled Rose Bengal or a functional derivative of Rose Bengal.