In an investigation into the electrophilic nitrosation reactions of a series of 4,6-disubstituted pyrimidine derivatives, a subtle interplay between the electronic nature of the C-4 and C-6 substituents and reactivity was found where these were chloro-, mono- or disubstituted amino groups. Effects such as the presence of an aryl group or two alkyl groups on the amino moiety impede the progress of the reaction despite the presence of a second activating group.
Reference:
Van der Westhuyzen, CW, Rousseau, AL and Parkinson, CJ. 2007. Effect of substituent structure on pyrimidine electrophilic substitution. Tetrahedron -London, Vol. 63, pp 5394-5405
Van der Westhuyzen, C. W., Rousseau, A., & Parkinson, C. (2007). Effect of substituent structure on pyrimidine electrophilic substitution. http://hdl.handle.net/10204/1370
Van der Westhuyzen, Christiaan W, AL Rousseau, and CJ Parkinson "Effect of substituent structure on pyrimidine electrophilic substitution." (2007) http://hdl.handle.net/10204/1370
Van der Westhuyzen CW, Rousseau A, Parkinson C. Effect of substituent structure on pyrimidine electrophilic substitution. 2007; http://hdl.handle.net/10204/1370.