2-Amino-4,6-diphenyl-1,3,5-triazine formation

Starting with 2,4-diphenyl-1,3,5-triazine and KNH2-NH3, adduct 63 (Table XIII) is formed.116 The reaction mixture slowly leads to 2-amino-4,6-diphenyI-l,3,5-triazine by a mechanism that is shown by l5N labeling to consist of an addition-elimination process. Therefore, adduct 63 is likely to be a true reaction intermediate for the Chichibabin reaction. Although a related substrate, 2-methyIthio-4,6-diphenyl-1,3,5-triazine, gives the 2-amino derivative exclusively by the ANRORC mechanism, which is likely to involve the addition of NH2" to a phenyl-bearing position in the initial step, the formation of such adducts as 64 has not been reported.116... 

Treatment of 3-amino-5-hydrazino-l,2,4-triazole with benzil produced 2-amino-6,7-diphenyl-[l,2,4]triazolo[5,l-c][l,2,4]triazine via either direct formation involving cycliz-ation on the triazole N-1 or attack at N-4 of the triazole to yield the [3,4-c] compound which rearranged to the [5,1-c] isomer (76JCS(P1)1492). Ring closure of 3,4-diamino-1,2,4-triazines with carboxylic acids is also a route to various [l,2,4]triazolo[5,l-c][l,2,4]triazines (64CB2173). 

---