Abstract: Here we report the results of experimental studies on the development of a new three-pot method for the synthesis of 2,3,4a, 6,7,8a,
9,10-octaaza-4,8-dioxo-3,4,4a, 7,8,8a, 9,9a, 10,10a-decahydroanthracene from urea by nitration of urea to symmetric N,N'-dinitrourea followed by
the reaction of the latter with bis(hydrazine)glyoxal when heated. In this case, at least a twofold excess of N,N'-dinitrourea is required due to its fast
hydrolysis, which also facilitates the pH shift of the medium towards the acidic required for tricyclization. The liberation of the bishydrazone salt of
N,N'-dinitrourea and its further heating in water were shown to furnish both a monocyclic and a tricyclic product, depending on the reaction
conditions. At this point, this is the simplest and most efficient method for the synthesis of tricyclic compound 1 because the total yield rises from 4%
to 33%, with the time costs considerably reduced as compared to the other known methods.
Index terms: N,N'-dinitrourea, glyoxal, bis(hydrazone)glyoxal, tricyclization, octaazadioxodecahydroanthracene.