While 8 behaves like NPBDP in that intermolecular reactions occur exclusively in a 1, 2- fashion, it was quite surprising to find that reaction of 8 with bifunctional nucleophiles such as N, N-dimethylguanidine gave the 1, 2-adduct 11 without concomitant intramolecular cyclization.(In contrast, the reaction of NPBDP with guanidines does yield the 4-pyrimidones via intramolecular cyclization of the initial add~ ct.~)
