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

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 compound s. Aldehydes carrying different hydrophobic substituents were used and the five series were designed so that the hydrophobicity also varied among cong eners. Retention parameters were measured by HPLC employing a deactivated a lkyl-bonded silica column and different eluent systems (methanol-aqueous bu ffer, acetonitrile-water). The hydrophobicity chromatographic parameters (l og 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 th e experimental values. Correlations between different hydrophobicity indice s are reported and discussed.