R.E. Moskalyk

Benzothiadiazine dissociation constants. Part I. Ultraviolet spectrophotometric pKa determinations

Thermodynamic values for the dissociation constants of a number of benzothiadiazines and diazoxide were determined by the ultraviolet spectrophotometric method. Resolution of the overlapping acidity constants was achieved by employing a computer program of successive approximations.

Benzothiadiazine dissociation constants. Part II. The order of deprotonation

Superimposed ultraviolet absorption spectra have been used to determine the order of deprotonation of the two acidic hydrogen atoms of certain benzothiadiazines. This ultraviolet spectral information on the benzothiadiazines and diazoxide, together with nuclear magnetic resonance spectral studies and the effect of substitution at the 3-position, suggests that the hydrogen atom at the 2-position is the more acidic.