Электронное влияние ароматического кольца в положении 2 на H/D обмен метильных протонов в пиримидине

Abstract

The H/D exchange of hydrogen atoms of methyl groups in pyrimidines containing a phenyl or substituted pyrazole ring in position 2, namely, 2-phenyl-4-methyl-5-ethoxycarbonyl-, 2-phenyl-4-methyl-5-acetyl and 2-(3,5 dimethylpyrazolyl-1-)-4-methyl-5-acetylpyrimidines was studied. It has been shown that the rate of deuterium exchange depends on the electronic influence of the lateral aromatic ring associated with pyrimidine. When a phenyl group is introduced into position 2 of the pyrimidine ring almost immediately after adding deuterated sodium methoxide (CD3ONa) to the CD3OD solution, the signals from the protons of the ester or acetyl groups disappear.