Chemoselective reactions of amidines: selective formation of iminopyrimidine regioisomers
The dramatic effect of base on the chemoselectivity of the reaction of amidines with substituted 3-phenyl-2-propynylnitriles is demonstrated. Amidine 1 can be added to cyanoalkyne 2 to give iminopyrimidine isomer 3 with high selectivity. The addition of 2 equiv of NaHMDS completely reverses the selectivity of the reaction, yielding isomer 4 almost exclusively. This method has been used to prepare a variety of substituted 4-iminopyrimidines.
McCauley
JA
Department of Medicinal Chemistry, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
Theberge
CR
Liverton
NJ