4''-O-(omega-Quinolylamino-alkylamino)propionyl derivatives of selected macrolides with the activity against the key erythromycin resistant respiratory pathogens.

Four macrolides-6-O-methyl-8a-aza-8a-homoerythromycin, clarithromycin, azithromycin and azithromycin 11,12-cyclic carbonate, have been selected for the construction of a series of new quinolone derivatives. The quinolone moiety is connected to the macrolide scaffold via a diaminoaklyl 4''-O-propionyl ester chain of varying length. At the terminus the linker is attached via one of the nitrogen atoms in the linker at C(6) or C(7) of the quinolone. Many of compounds described, particularly clarithromycin derivative 37, and azithromycin derivatives 48 and 55, exhibited excellent antibacterial activity against a wide range of clinically relevant macrolide-resistant organisms, with profiles superior to that of telithromycin, an enhanced spectrum ketolide.

Evaluation of alkali metal binding selectivities of caged aza-crown ether ligands by microelectrospray ionization/quadrupole ion trap mass spectrometry

Microelectrospray ionization mass spectrometry (MESI-MS) is used to evaluate alkali metal binding selectivities of a variety of macrocyclic compounds. Well-studied crown ethers are used to validate the MESI-MS method. A quantitative correlation between MESI mass spectral ion intensities and solution equilibrium distributions of complexes is obtained for the mixtures containing a single host and different alkali metal guest ions. The MESI-MS method is successfully applied for the determination of the alkali metal binding selectivities of a series of cage-functionalized aza-crown ethers and relevant model compounds in methanol and chloroform solutions. The binding selectivities parallel previous results obtained using conventional spectrophotometric extraction methods. Structural differences in the host compounds, such as the presence of a cage functionality, binding cavity size, and overall flexibility, cause significant changes in the binding selectivities.