Topic
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.
Papers published on a yearly basis
Papers
More filters
TL;DR: In this article, a 1,8-dioxo-octahydroxanthenes from aldehydes and dimedone using non-toxic, easily prepared and recyclable catalyst (Sm2O3/SiO2) as a silica supported rare earth element under solvent-free conditions.
Abstract: Eco-friendly one pot synthesis is developed for 1,8-dioxo-octahydroxanthenes from aldehydes and dimedone using non-toxic, easily prepared and recyclable catalyst (Sm2O3/SiO2) as a silica supported rare earth element under solvent –free conditions. four of the synthesized compounds showed promising ABTS (3i, 68.7; 3b, 59.2; 3h, 50.2 inhibition%) compared with ascorbic acid.
4 citations
TL;DR: The title compound, C35H35ClN4O3, resulted from a spirolactam ring closure of rhodamine B dye and the xanthene ring system is approximately planar.
Abstract: The title compound, C35H35ClN4O3, resulted from a spirolactam ring closure of rhodamine B dye. The xanthene ring system is approximately planar [r.m.s. deviation = 0.050 (9) A for the xanthene ring]. The dihedral angles formed by the spirolactam and 5-chloro-2-hydroxybenzene rings with the xanthene ring system are 87.9 (7) and 79.1 (7)°, respectively.
4 citations
TL;DR: In contrast to other o-quinones, photochemical reaction of 1,2-naphthoquinone with xanthene gave a 1 : 1 adduct in which the Xanthene moiety is attached to position C4, i.e., 1,4-dihydro-2-hydroxy-4-xanthyl-1-ketonaphthalene as mentioned in this paper.
Abstract: In contrast to other o-quinones, photochemical reaction of 1,2-naphthoquinone with xanthene gave a 1 : 1 adduct in which xanthene moiety is attached to position C4, i.e., 1,4-dihydro-2-hydroxy-4-xanthyl-1-ketonaphthalene (2a). The analogous photo-adducts, 2b, 2c, and 2d, were obtained by the photochemical reaction of 3-chloro-1,2-naphthoquinone, 3-bromo- 1,2-naphthoquinone, and 6-bromo-1,2-naphthoquinone with xanthene, respectively. The dynamic aspect of these reactions was also examined using the CIDNP technique and the reaction mechanism was discussed.
4 citations
TL;DR: Two cyclic oligoureas with 64- and 80-membered rings in which two sets of three or four rigid xanthene units are connected via flexible diphenyl ether units were synthesized by a stepwise fragment condensation, finding that intermolecular hydrogen bonds between the macrocycles were not observed.
Abstract: Two cyclic oligoureas with 64- and 80-membered rings in which two sets of three or four rigid xanthene (X) units are connected via flexible diphenyl ether (D) units were synthesized by a stepwise fragment condensation. The compounds were characterized by 1H NMR and ESI mass spectrometry. The structure of the cyclic octamer (XXXDXXXD) was additionally confirmed by single crystal X-ray analysis. The molecule assumes a strongly folded conformation with distorted C2-symmetry, stabilized by intramolecular hydrogen bonds. Surprisingly, intermolecular hydrogen bonds between the macrocycles were not observed. 1H NMR spectra suggest a C2 symmetrical conformation of the octamer in solution also, while its kinetically stable complex with three chloride ions has no symmetry element at all.
4 citations
TL;DR: Two marine sesquiterpene quinones, (+)-cyclospongiaquinone-1 and (−)-dehydrocyclospongequinones, were efficiently synthesized from commercially available (+)-sclareolide.
4 citations