Pyrimidine reactions. XIV. The butylaminolysis of substituted methoxy-and methylthio-pyrimidines

Abstract

Aminolyses of 2- and 4-methoxy (or methylthio) pyrimidines bearing C- methyl, CC?-dimethyl, 5-bromo, or 5-nitro substituents have proved of value, in the absence of added solvent, for preparing the corresponding n- and t-butyl-aminopyrimidines. When these displacements are followed spectrometrically, the apparent first-order rate constants indicate mild deactivation by additional methyl substituents, moderate activation by a bromo substituent, and profound activation by a nitro substituent. Ionization constants and ultraviolet spectra of relevant pyrimidines are recorded.