The chemistry of .beta.-enaminonitriles as versatile reagents in heterocyclic synthesis

Synthesis of [1,2,3]triazolo[1,5-a][1,2,4]triazolo[5,1-c]pyrazines

“…This type of reaction, but with the two groups in the same ring, had been observed in some heterocycles, for example in 2-amino-3-cyanopyridine. 9,10 In addition, [1,2,3]triazoloazines with a bridgehead nitrogen atom exhibit valence tautomerism and could suffer lost of dinitrogen forming azine derivatives, via the corresponding diazomethylazines.…”

“…1,2 Recently we designed novel approaches to β-(1,2,3-triazol-1-yl)-α-amino acid derivatives, 3 β-(imidazol-1-yl)-α-amino acid derivatives, 4 As an extension of these investigations we describe here further functionalization of the [1,2,3]triazolo [1,5-a]pyrazine system and the synthesis of some [1,2,3]triazolo [1,5-a] [1,2,4]triazolo [5,1-c]pyrazines. We focused on the formation of 1,2,4-triazole ring fused to the N(5)=C(4)(NH 2 ) unit of the amine 1, 5 ( Figure 1), by the general synthetic method that use N,Ndimethylformamide dimethyl acetal (DMFDMA), hydroxylamine hydrochloride, and polyphosphoric acid (PPA) as the main required reagents, 7,8 thinking that this procedure could be extended to the heterocyclic system 1.…”

Synthesis, reactions and antitumor activity of new β-aminovinyl 3-pyrazolyl ketones

“…13,14 Their synthetic applications have been extensively reviewed. 12,[15][16][17][18][19][20][21][22][23][24][25][26][27] Furthermore, many enaminones were found to exhibit several biological activities as antitumor, antibacterial and anticonvulsant agents. 28,29 In the light of these facts, it was thought interesting to synthesize a new series of β-dimethylaminovinyl 3-pyrazolyl ketones 4 which are novel enaminones that have been unreported hitherto and study their 1,3-dipolar cycloaddition to the nitrilimines, generated in situ by base-catalyzed dehydrohalogenation of hydrazonoyl halides R-C(X)=NNH-Ar 2.…”

Reactions of nitrilimines with heterocyclic amines and enamines. Convenient methodology for synthesis and annulation of heterocycles

“…Several review articles covering their chemistry have appeared in literature. [10][11][12][13][14][15][16][17] A survey of these reviews together with those dealing with the chemistry of nitrilimines and their hydrazonoyl halides precursors reveals that little focus, if any, has been made hitherto on reactions of nitrilimines with enamines and heterocyclic amines. Our intention in this review is to remedy this situation through presenting the highlights of such reactions that have been reported from our laboratory and from others within the period from 1985 to mid 2006 and contained in Chemical Abstracts.…”