An efficient solid phase strategy for the versatile functionalisation of xanthene dyes for conjugation and labelling of biomolecules is presented. The low cost, high purity and excellent spectral properties of the obtained materials provide an attractive alternative for the labelling of a wide range of molecules.

Reduction of dixanthylidene with potassium or lithium resulted in formation of the antiaromatic dianion in high yield. Attempts to form the dianion by excited-state deprotonation of dixanthene with n-butyllithium/TMEDA resulted in formation of the tetraanion from deprotonation ortho to the oxygen. Orientation of the sp(3) hydrogens presumably allows preferential deprotonation of the xanthene ri...

In the title compound, C(28)H(32)N(4)O(3), the dihedral angle between the planes of the xanthene ring system and the spiro-lactam ring is 85.99 (3)°. Mol-ecules are linked by inter-molecular O-H⋯O and N-H⋯O hydrogen-bonding inter-actions.

The title compound, C(12)H(12)N(4), was synthesized by the reaction of hydrazine hydrate and 9-methyl-3,4,6,7-tetra-hydro-2H-xanthene-1,8(5H,9H)-dione in ethanol. In the crystal, the mol-ecule lies across an inversion centre. The pyridazine rings are coplanar and the C(6) rings adopt envelope conformations.

I. The Biological Liberation of Morphine from Codeine in the Rat. T. K. Adler and F. H. Shaw 1 II. The Effect of Prolonged Morphine Administration on the In Vivo and In Vitro Conjugation of Morphine by Rats. Howard L. Zauder 11 III. Adenine Intoxication in Relation to In Vivo Formation and Deposition of 2,8-Dioxyadenine in Renal Tubules. Frederick S. Philips, John B. Thiersch and Aaron Bendich ...

In the title compound, C(38)H(42)N(4)O(4)·C(2)H(6)O, prepared via a spiro-lactam ring-formation reaction in a rhodamine dye, the xanthene ring system is approximately planar (r.m.s. deviation = 0.0014Å) and subtends dihedral angles of 88.10 (3) and 86.92 (4)° with the spiro-lactam (r.m.s. deviations = 0.0012 Å) and benzene rings, respectively. The crystal structure consists of chains parallel t...

In the title compound, C(21)H(18)O(3), the xanthene system and the meth-oxy-phenyl ring are practically orthogonal with a dihedral angle between their mean planes of 89.27 (3)°. The meth-oxy group attached to the phenyl ring makes a C-O-C-C torsion angle of 11.56 (18)°. In the crystal, mol-ecules are linked by C-H⋯O inter-actions into chains along [010]. Weak C-H⋯π inter-actions also occur.

An efficient route is reported to 5- and 6-carboxy-X-rhodamines (compounds 1 and 2) that contain multiple n-propylene or gamma,gamma-dimethylpropylene groups bridging terminal nitrogen atoms and the central xanthene core. Gram quantities of these dyes are synthesized from inexpensive starting materials. The isolated products are activated by selective transformation of the carboxylic acid group...

Synthesis, characterization and reactivity studies of a hetero-dicopper complex, particularly towards oxygen reduction are presented. A bischlorido copper(II) trishistidine-type coordination unit is positioned directly above copper porphyrin unit. The close distance between the two fragments secured by rigid xanthene backbone. Surprisingly, dinuclear complex not active unlike earlier published ...

The β-lactam ring of the title compound, C(35)H(23)NO(2), is nearly planar with a maximum deviation of 0.003 (3) Å from the mean plane. It makes dihedral angles of 17.4 (2), 85.22 (17) and 65.39 (16)°, respectively, with the phenyl, xanthene and anthracene ring systems. In the crystal structure, there are intra-molecular C-H⋯O and C-H⋯N contacts and mol-ecules are also linked by C-H⋯π inter-act...