The rates of hydrolysis of α-R-α-(methylthio) methylene Meldrum's acids (8-R with R= H, Me, Et, s-Bu, and t-Bu) were determined in basic and acidic solution in 50% DMSO-50% water (v/v) at 20° C. In basic solution (KOH), nucleophilic attack to form a tetrahedral intermediate () is rate limiting for all substrates (k 1OH). In acidic solution (HCl) and at intermediate pH values (acetate buffers), water attack (k 1H2O) is rate limiting for 8-Me, 8-Et, and 8-s-Bu; ...
