Xanthene carboxamides

A similar potency enhancement is seen for the xanthene carboxamide quaternary salt (16) (CCRl IC50 = 0.9 nM), where the simple... 

Naya, A., Ishikawa, M., Matsuda, K, Ohwaki, K., Saeki, T., Noguchi, K., and Ohtake, N. (2003) Structure-activity relationships of xanthene carboxamides, novel CCRl receptor antagonists. Bioorganic and Medicinal Chemistry, 11, 875-884. 

Fluorenone derived linker 17 prepared in two steps was coupled to aminomethyl-PS via DIPCDI [21]. Due to the presence of an electron-withdrawing carboxamide group, the release of carboxylic acids from this support requires strong acids, such as trifluoromethanesulfonic acid (TFMSA) (Scheme 1). Insertion of an oxygen adjacent to the biphenyl rings to the fluorenone scaffold provides xanthene 18 handle [22]. The oxygen is strategically located to decrease the acid concentration required... 

The central ring systems found to yield antiviral compounds have included fluorene (fluorenone), dibenzofuran, dibenzothiophene, fluoranthene, anthraquinone, acenaphthene, xanthene, thioxanthene, phenothiazine, carbazole, phenanthrene and others. The side chains were represented by basic ethers, basic ketones, basic esters plus carboxamides, sulphonamides, alkanols, methylene and others attached to the various ring systems. The amine function was usually substituted to the tertiary amine with various alkyl substituents although a few ring types (e.g., pyrrole or piperidino) were synthesized. 

Hydroxy-9-(4-carboxyphenyl) xanthene Cleavage TFA Product after cleavage Carboxamide [93]... 

CA Index Name Spiro[isobenzofuran-l(3//),9 -[9//] xanthene]-5-carboxamide, N-[4-[bis(2-pjnidinylmethyl) amino]phenyl]-2, 7 -dichloro-3, 6 -dihydroxy-3-oxo-, potassium salt (1 2)... 

---