Pyrimidine reactions. Part XXII. The relative reactivities of some corresponding chloro-, bromo-, and iodo-pyrimidines in aminolysis

Abstract

Times of half-completion (t_1/2 values) are reported for the aminolysis by isopentyl- and 1,4-dimethylpentyl-amine of 2-halogeno-, 5-bromo-2-halogeno-, 2-halogeno-4,6-dimethyl-, and 4-halogeno-2,6-dimethyl-pyrimidines. Within each group the bromopyrimidine is most reactive and the chloropyimidine generally least reactive, but the greatest difference in rate is only about three-fold.

Eight isopentyl- or 1,4-dimethylpentyl-aminopyrimidines derived from these reactions are characterized, and syntheses for 2,5-dibromo-, 1,2-dihydro-5-iodo-2-oxo-, 2-chloro-5-iodo-, and 4-bromo-2,6-dimethyl-pyrimidine are described. Ionization constants and u.v. spectra for solutions in cyclohexane are tabulated.