Beilstein J. Org. Chem.2013,9, 1819–1825, doi:10.3762/bjoc.9.212
used for the activation of chloropyrimidines toward a nucleophilic substitution reaction with amines. The subsequent treatment of the obtained products with aq H2SO4 can lead to either N-denitrosation to obtain 4,6-pyrimidinediamines or to a Fischer–Hepp type rearrangement to obtain 5-nitroso-4,6
-pyrimidinediamines. It was found that the outcome of the reaction strongly depends on the structure of the pyrimidines. Activation of the pyrimidine ring by three groups with a positive mesomeric effect is crucial for the intramolecular nitroso group migration.
Keywords: Fischer–Hepp rearrangement; nitrosation; 5
-nitrosopyrimidines; nucleophilic substitution; pyrimidinediamines; Introduction
The pyrimidine moiety is an important structural motif in natural products and therefore frequently used as a building block for pharmaceutical agents [1][2]. It is well-known that chemical properties of pyrimidines depend on the π
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Graphical Abstract
Scheme 1:
General behavior of electrophilic and nucleophilic substitution reactions of pyrimidines.