A convenient and efficient procedure for the synthesis of 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes by condensation of 2-naphthol and aldehydes in the presence of Methylimidazolium hydrogensulfate, as a Brönsted acidic ionic liquid ([Hmim]HSO4), is described. Both aromatic and aliphatic aldehydes reacted easily to afford the corresponding 14-aryl or alkyl-14H-dibenzo[a,j]xanthenes in good yiel...

The title compound, C(20)H(20)O(5), was synthesized from the reaction between 3-methoxysalicaldehyde and 1,3-cyclo-hexa-nedione in the presence of palladium(II) chloride. The two fused xanthene rings and one of the six-membered cyclo-hexane rings adopt envelope conformations, while the other six-membered cyclo-hexane ring is in a chair conformation. The mol-ecular packing is stabilized by weak ...

The title compound, C(36)H(36)N(4)O(4), was prepared as a spiro-lactam ring formation of the rhodamine dye for comparison with a ring-opened form. The xanthene ring system is approximately planar [r.m.s. deviations from planarity = 0.023 (9) Å for the xanthene ring]. The dihedral angles formed by the spiro-lactam and 1,3-benzodioxole rings with the xanthene ring system are 86.8 (1) and 74.3 (1)...

The title compound, C28H20O4, was synthesized by a bimolecular Zn-HCl reduction in glacial acetic acid using the meth-oxy-substituted xanthone as a starting material. The crystal structure shows that the 2,2'-meth-oxy-bixanthenyl-idene unit is an E-type conformation anti-folded conformer. The mol-ecule lies on an inversion center. The meth-oxy group is almost coplanar with the attached benzene ...

In the title compound, C(27)H(15)Br(2)ClO·C(3)H(7)NO, the xanthene moiety has a flattened boat conformation with a folding angle between the naphthalene units of 9.46 (3)°. The mean planes of the xanthene system and its 4-chloro-phenyl substituent are nearly perpendicular [dihedral angle = 89.43 (5)°]. The dimethyl-formamide solvent mol-ecule is disordered over two sets of sites with an occupan...

The title compound, C(35)H(38)N(4)O(3), was prepared as a spiro-lactam ring formation of rhodamine dye for comparison with a ring-opened form. The xanthene ring system is approximately planar. The dihedral angles formed by the spiro-lactam and phenol rings with the xanthene ring system are 85.7 and 109.4°, respectively. Each of the mol-ecules in the crystal structure contains one intra-molecula...

A simple and environmentally benign procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes by a one-pot condensation of 2-naphthol with aromatic aldehyde in the presence of [Et3NH][HSO4] as an acidic ionic liquid catalyst under solvent-free conditions has been developed. The reaction work-up is very simple and the catalyst can be easily separated from the reaction mixture and reused s...

In 1891 Guttmann and Ehrlich (P. Guttmann and P. Ehrlich, Berlin Klin. Wochenschr. 28:953-956, 1891) were the first to report the antimalarial properties of a synthetic, rather than a natural, material when they described the clinical cure of two patients after oral administration of a thiazine dye, methylene blue. Since that time, sporadic reports of the antimalarial properties of several xant...

In the title compound, C(20)H(22)O(5), an S(6) ring motif is formed by an intra-molecular C-H⋯O hydrogen bond, which contributes to the stabilization of the mol-ecule. In the xanthene system, the cyclo-hexane ring adopts a chair conformation, the cyclo-hexene ring adopts a half-boat conformation and the tetra-hydro-pyran ring adopts a half-chair conformation. The mean plane of the four essentia...

Three xanthene dyes with different anchoring groups, eosin Y (EY), dicarboxy-eosin Y (CEY) and sulfonated eosin Y (SEY) were employed to electrodeposit ZnO/dye hybrid thin films to study the effect of anchoring groups on the electrochemical self-assembly (ESA) of hybrid thin films. The adsorption stabilities of the dyes in oxidized form were in the order, CEY >> EY > SEY, as evaluated by Langmu...