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.

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.

Highly sensitive spectrophotometric determination of cobalt using o-hydroxyhydroquinonephthalein and hydrogen peroxide in the presence of mixed surfactants

Abstract: The effects of cobalt(II) and surfactants on the decomposition of various xanthene dyes by hydrogen peroxide have been systematically investigated. A simple and highly sensitive spectrophotometric determination of cobalt(II) (0.05 ∼ 1.2 Μg/10 ml) is proposed. The method is based on the catalytic effect of cobalt(II) on the oxidation of o-hydroxyhydroquinonephthalein (Qnph) by hydrogen peroxide. The proposed catalytic spectrophotometric determination was sensitive, selective, reproducible and virtually unaffected by the presence of other ions; the effective molar “desorptivity” was 4.2×108 l/mol per cm, Sandell sensitivity was 0.15 pg/cm2, and the relative standard deviation was 3.2% at 0.6 ng/10 ml (n=5). The selective assays of cobalt(II) in water samples were also investigated with satisfactory results (95% ∼ 101%).

Design and synthesis of a new dimeric xanthone derivative: enhancement of G-quadruplex selectivity and telomere damage

Abstract: Following the results we previously reported on a series of xanthene and xanthone derivatives as G-quadruplex stabilizing ligands, in order to obtain a more selective compound with respect to the previous generation of derivatives, we decided to modify the structure of the core ligand, specifically its aromatic extension. In particular, here we report the design, synthesis and activity data of a new compound obtained by dimerization of the xanthene core (HELIXA4C). The reported results show that extension of the aromatic core and the increase of the number of polar side chains led to a great enhancement of G-quadruplex selectivity and telomere damage capability, as derived using ESI-MS evaluation, in vitro cancer screening and specific immunofluorescence assays.