N-nitroso derivative of pyrrole moiety in Pyrrolopyrimidines

Is pyrrole nitrogen in pyrrolopyrimidine (and its derivatives) moiety is nucleophilic enough to form N-nitrosamine derivative? My practical experience suggests that it is not, and the pyrrole nitrogen very resistive to form N-nitroso derivative.
Thoughts and suggestions from this group are much appreciated.
Thanks and Best Regards