Open AccessSpectroscopic Study of the Basicity of 4,6-Dihydroxypyrimidine Derivatives
Author(s) -
Tuan Q. Vu,
N. V. Yudin,
Alexander A. Kushtaev,
Thanh X. Nguyen,
Sergey A. Maltsev
Publication year - 2021
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.1c00671
Subject(s) - protonation , chemistry , barbituric acid , nitro , medicinal chemistry , alkyl , stereochemistry , organic chemistry , ion
The protonation of a number of 4,6-dihydroxypyrimidine derivatives is studied, and the features of the electronic spectra of free bases and protonated forms are considered. It is shown that the alkyl substituents in position 2 increase the basicity of the compound, and the nitro group in position 5 leads to its decrease. In an acid medium (0.1-99.5% H 2 SO 4 ), 4,6-dihydroxypyrimidine, 6-hydroxy-2-methylpyrimidine-4(3H)-one, and 6-hydroxy-2-ethylpyrimidine-4(3H)-one have two protonation stages, barbituric acid is protonated in three stages, and 6-hydroxy-2-methyl-5-nitropyrimidine-4(3H)-one and 6-hydroxy-2-ethyl-5-nitropyrimidine-4(3H)-one form a monocation.