1,3,5-Triazine, phenyl-, Chichibabin amination

Furthermore, it was pointed out that, whereas the formation of the amino adduct is fast and the formation of the product slow, it is possible that an equilibrium exists among the starting materials, their 1 1 a-amino adducts, and their open-chain amidines (Scheme 11.54). When this is the case, one may expect that, if the amination of phenyl-1,3,5-triazine is stopped before complete conversion, the retrieved starting material should be N-labeled. This has indeed been found. This behavior is in agreement with that observed with the Chichibabin amination of 4- and 5-phenylpyrimidine. 

When 2-phenyl-l,3,5-triazine (8) is aminated with potassium amide in liquid ammonia at - 33 C a very slow Chichibabin reaction occurs, partly via the Sn(ANRORC) mechanism and partly via the SNAE process (ratio ca. 55 45). H NMR and l5N-labelling studies have demonstrated that in solution an equilibrium exists between the starting triazine, amine adducts, open-chain amidines and triazine product 9.53... 

Simig, G., Van der Plas, H. C. The SN(ANRORC) mechanism. XVII. An SN(ANRORC) mechanism in the amination of phenyl-1,3,5-triazine with potassium amide in liquid ammonia. A novel mechanism for the Chichibabin reaction. Red. Trav. Chim. Pays-Bas 1976, 95,125-126. 

Substituted triazines have been subjected to amination with potassium amide in liquid ammonia. With 2,4-diphenyl-l,3,5-triazine (260), treatment with potassium amide in liquid ammonia afforded a typical Chichibabin product, 2-amino-4,6-diphenyl-I,3,5-triazine (261) (Scheme 89) (76RTC 113). Through labeling experiments, it was established that the amination was not occurring via an Sn(ANRORC) mechanism, but rather by an Sn(AE) process. However, Sn(ANRORC) does occur during the amination of phenyl-1,3,5-triazine, and this has been elaborated upon in Section II,B,1. 

The examples shown are illustrative of the many easy nucleophilic additions to the polyaza-azines both 3-phenyl-l,2,4,5-tetrazine and 1,3,5-triazine itself add ammonia and simple amines (contrast the requirement for hot sodamide (Chichibabin reaction) for pyridine (8.3.1.2)) and thus amino and alkyamino derivatives can be obtained via oxidative trapping with permanganate. 

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