Ring degenerate transformations of azines

Applications of Purine Ring Opening in the Synthesis of Imidazole, Pyrimidine, and New Purine Derivatives

“…The aminolysis of 2-halo-or thiopurines with 15 N labelled KNH 2 /NH 3 led to an incorporation of 15 N into the purine ring N-1 position, thus proving the S N (ANRORC) mechanism. [15,23] However, no ring opening was observed in 6-chloro-and 6methylthiopurine reactions with 15 N labelled KNH 2 /NH 3 . The reaction of 2,6-dichloropurine (30: Y=X=Cl) with KNH 2 /NH 3 at first yielded 6-amino-2-chloropurine (30: Y=NH 2 ; X=Cl) through a regular S N Ar process.…”

1,2,4-Triazine Chemistry Part IV: Synthesis and Chemical Behavior of 3-Functionalized 5,6-Diphenyl-1,2,4-triazines towards Some Nucleophilic and Electrophilic Reagents

“…The amino group at C ‐3 did not originate from ammonia but from the triazine ring itself. This amination is an example of the so‐called ring‐degenerate transformation reaction (Scheme ) .…”

“…Many methods were used for the synthesis of 3‐amino‐5,6‐diphenyl‐1,2,4‐triazines 37 . Efficient method was achieved from cyclocondensation of benzil with aminoguanidine bicarbonate in refluxing n ‐butanol , Also from amination of 3‐chloro‐1,2,4‐triazine 20 and 3‐methylsulfonyl‐1,2,4‐triazine 53 with some amines (Scheme ) .…”

Use of the ring opening reactions of 1,3,5-triazines in organic synthesis (review)

“…The simplest example of a reaction taking place according to this scheme is the reaction of 1,3,5-triazine with amidines X = Y = N [36][37][38][39]. A series of examples of the use of 1,3-C-binucleophiles in reactions with 1,3,5-triazines have been described.…”