Synthesis and correlations between experimental and calculated lipophilic indices of new 1,2-benzisothiazole derivatives with potential antimicrobial activity.

Five series of new hydrazones (1a-m, 2a-m, 3a-m, 4a-m, 5a-m) with potential antimicrobial activity were synthesized from cyclic (1 and 4) or acyclic (2, 3 and 5) 1,2-benzisothiazolylhydrazides and characterized. Condensation of the appropriate hydrazide with aldehydes afforded the designed compounds. Aldehydes carrying different hydrophobic substituents were used and the five series were designed so that the hydrophobicity also varied among congeners. Retention parameters were measured by HPLC employing a deactivated alkyl-bonded silica column and different eluent systems (methanol-aqueous buffer, acetonitrile-water). The hydrophobicity chromatographic parameters (log k') were compared with those provided by measurement of partitioning of solutes between n-octanol and water (log P), and with theoretical partition coefficients, calculated by a fragmental method and scaled according to the experimental values. Correlations between different hydrophobicity indices are reported and discussed.