Aminolysis of methoxy groups in pyrimidine derivatives. Activation by 5‐nitroso

The nucleophilic substitution of 2‐mefhoxy groups in pyrimidine derivatives was strongly activated by introduction of a 5‐nitroso group on to the pyrimidine ring. The aminolysis of several 2‐methoxy‐5‐nitrosopyrimidine derivatives was performed at room temperature in hydroxylic as well as in non‐hydroxylic media with different primary amines in short time and good yields. The aminolysed substrates include 6‐(per‐O‐acetyl)glycosyl]aminopyrimidines which afforded the corresponding 2‐aminopyrimidines without harming the acetyl protecting groups of the sugar moiety.