Kinetics and Mechanism of the Anilinolysis of Bis(2,6-dimethylphenyl) Chlorophosphate in Dimethyl Sulfoxide

Abstract

pKa values for the anilinium ions determined in DMSO, an approximate straight line is obtained when they are plotted against those determined in water. 4 Spillane and coworkers reported that the βX value for the reactions of N-phenyl sulfamoyl chloride (PhNHSO2Cl) with X-anilines in DMSO is similar when determined using the pKa values of anilines measured in water (βX = 0.69) and DMSO (βX = 0.62). 5 Accordingly, it may be inferred that the βX values in Table 1 are reasonably positive. The pKa and σ values of deuterated anilines are assumed to be the same as those of anilines. The pKa(X) values of deuterated X-anilines may be slightly greater than those of X-anilines, however, the difference is too small to be taken into account. 6 Figures 1 and 2 show the Hammett (log kH(D) vs σX) and Bronsted [log kH(D) vs pKa(X)] plots, respectively, for substituent X variations in the nucleophiles. The rate consistently increases with a more electrondonating substituent X in the nucleophile, which is consistent with a typical nucleophilic substitution reaction with positive charge development at the nucleophilic N atom in the transition state (TS). The magnitudes of the ρX and βX values with the deuterated anilines are slightly greater than those with the anilines, suggesting more sensitive to substituent effects of the deuterated anilines compared to the