A study of thermodynamic acidities of carbon acids by AM1

Monocyclic carbon acids 1–8 have been studied by the semiempirical computational method AM1 in an attempt to develop a methodology for estimating pKs. The results indicate that there is a good correlation between [ΔH f (R − ) − ΔH f (R-H)] obtained computationally and the pKs measured in DMSO. The pKs of 9a, 9b, 10, 11 (tetronic acid), and the dioxolane dione 12 are predicted on the basis of this correlation.