A. P. Kroon, H. Plas
Sep 2, 2010
Citations
0
Influential Citations
4
Citations
Journal
Recueil des Travaux Chimiques des Pays-Bas
Abstract
Amination of the 2-X-4,6-diphenylpyrimidines (X=F, Cl, Br) with potassium amide in liquid ammonia yields the corresponding 2-amino compounds, and in addition some dehalogenated product in the case of X = Br. It is proved, using the corresponding [1,3-15N]-labelled pyrimidines, that for the 2-chloro and 2-bromo compounds the amination goes to the extent of about 70% via a ring-opening [SN(ANRORC) mechanism] but that in the amination of the 2-fluoro compound no ring-opening takes place [SN(AE) process]. One of the supposed intermediates during the ring-opening i.e. 3-(cyanoimino)-1,3-diphenyl-1-propenamine could be isolated. Also the amination of 2-chloro-4-phenylquinazoline with potassium amide occurs to the extent of about 70% via the SN(ANRORC) mechanism. If instead of potassium amide in liquid ammonia an ethanolic ammonia solution is used at elevated temperatures, a considerable amount of the corresponding 2-amino compound is also formed via the ring-opening process, i.e. 34-67% (depending on the ammonia concentration). 2-Chloro- and 4-chloro-quinazoline behave similarly on reaction with ethanolic ammonia.