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.

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 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...

In the title compound, C19H16BrClO4, both the fused xanthene rings and one of the cyclo-hexane rings adopt envelope conformations, while the other cyclo-hexane ring is in a chair conformation. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds, forming infinite chains running along [10-1] incorporating R 2 (2)(16) ring motifs. In addition, C-H⋯π inter-actions and weak π-π stacking in...

In the title mol-ecule, C(36)H(25)NO(3), the β-lactam ring is essentially planar, with a dihedral angle of 3.3 (2)° between the two separate three-atom N/C/C planes. The β-lactam ring makes dihedral angles of 28.45 (14), 87.4 (1) and 51.8 (1)° with the mean planes of the benzene, xanthene and anthracene ring systems, respectively. In addition to a weak intra-molecular C-H⋯N hydrogen bond, the c...

Natural dibenzo-α-pyrones are an important group of metabolites derived from fungi, mycobionts, plants and animal feces. They exhibit a variety of biological activities such as toxicity on human and animals, phytotoxicity as well as cytotoxic, antioxidant, antiallergic, antimicrobial, antinematodal, and acetylcholinesterase inhibitory properties. Dibenzo-α-pyrones are biosynthesized via the pol...

A rhodium-catalysed stitching reaction between 2-(silylethynyl)arylboronates and 2-(silylethynyl)aryl bromides has been developed for the synthesis of unsymmetric dibenzo[a,e]pentalenes. The introduction of appropriately sized silyl groups on the starting substrates led to a high crossover selectivity without using an excess amount of either substrate. The present stitching reaction could produ...