Synthesis and acidic properties of 1,2-benzisothiazolyltetrazoles and analogous alkanoic acids

A new convenient method to synthesize some tetrazolyl derivs. of 1,2-benzisothiazole, e.g. I (R = H, Me, Cl, O2N) is reported. The pKa of a series of 5-(1,2-benzisothiazolyl)tetrazoles and of the analogous 1,2-benzisothiazolyllalkanoic acids were detd. by potentiometry in methanol/water and compared with literature data. The acidic properties are discussed for possible linear free energy relationship and correlation with the biol. activity. The physico-chem. properties of two series are strictly correlated but do not appear to be responsible for the modulation of their biol. activity.