Synthesis and antibacterial activity of pyridazino[4,3-b]indole-4-carboxylic acids carrying different substituents at N-2.

The synthesis and the in vitro evaluation of antibacterial activity of new pyridazino[4,3-b]indole-4-carboxylic acids 2-4, 6 against some selected representative of Gram-positive and Gram-negative bacteria are reported. The role of the lipophilicity in the modulation of the antibacterial activity of the tested compounds is discussed. All the synthesized compounds appear quite weak against Gram-positive bacteria, whereas have no significant activity against Gram-negative bacteria.

Synthesis and antibacterial activity of 2-aryl-2,5-dihydro-3(3H)-oxo-pyridazino[4,3-b]indole-4-carboxylic acids.

The in vitro antibacterial and antifungal activities of a series of pyridazinoindolonic acids II against some selected representative of Gram-positive, Gram-negative bacteria and fungi have been investigated. Some interesting observations among the structural features necessary for high antibacterial activity are presented and discussed.

X-ray crystal structure, partitioning behavior, and molecular modeling study of piracetam-type nootropics: insights into the pharmacophore.

To detect possible molecular determinants of amnesia-reverting activity, the conformational properties of a number of rigid and flexible piracetam-type cognition enhancers have been assessed by X-ray diffraction, NMR spectroscopy, and ab initio and high-temperature-quenched molecular dynamics (QMD) calculations. The structures of the preferred conformers in solution derived from 1H-NMR spectral analysis were in good agreement with those found by QMD calculations. Interestingly, the calculation of the average molecular lipophilicity potential on the water-accessible surface of the selected conformers was helpful in interpreting the partitioning behavior observed by measuring octanol-water partition coefficients and capacity factors in reversed-phase high-performance liquid chromatography.

Linear solvation energy relationships in reversed-phase liquid chromatography. Examination of RP-8 stationary phases for measuring lipophilicity parameters.

Molecular lipophilicity can be expressed by log P or more conveniently by log kw, determined by the so-called "shake-flask" (SF) technique or by reversed-phase high-performance liquid chromatography (RP-HPLC), respectively. In the present study, the lipophilicity of a large set of solutes was measured by RP-HPLC on a silanol-deactivated octylsilane (OS) reversed phase, namely Inertsil OS (IN). IN lipophilicity parameters were found to be fairly well correlated with log P.

Synthesis and structure-antimicrobial activity relationships of quaternary ammonium derivatives of perhydropyrrolo-[3,4-c]pyridine.

A large homologous series of quaternary ammonium derivatives of perhydropyrrolo[3,4-c]pyridine 5 was synthesized and tested for in vitro antibacterial activity against different Gram-positive and Gram-negative bacteria. Compounds 5 proved to be always more potent than benzalkonium chloride, taken as reference. Antibacterial activity, expressed as log 1/MIC, was found linearly related to lipophilicity up to C13-C14 homologs, where a break in the linear relationship was observed.