AM1 theoretical study on the mechanism of 1,3-dipolar cycloaddition reaction of 1,2,4-triazepine and formonitrile oxide

Advances in 1,2,4-triazepines chemistry

“…Synthesis of 1,2,4-triazepines. The reaction of tetrachloro-cyclopropene (10), which functions as both a reactant and reaction solvent, with diphenyl nitrilimine (11), generated in situ 37 from triethyl amine and N-phenyl benzenecarbohydrazonoyl chloride, at room temperature gave 1,2,4-triazepine 15 in 93% yield (Scheme 1). 33 The preparation of 1,2,4-triazepine 18a was reported for the rst time by Loss et al 38 derivative 5 was obtained in 70% yield from heating 18a with phosphorus pentasulde in acetonitrile, 41 or heating 18a with tetraphosphorus decasulde in acetonitrile.…”

Conventional and microwave irradiation assisted synthesis of new 1,2,4‐triazepine‐3‐thiones

“…Viallefont and his co-workers reported on the methods used to prepare various derivatives of 1,2,4-triazepines disubstituted by oxo, thioxo, methoxy or methylthio groups [22]. Interestingly, triazepines and their fused derivatives exhibit interesting biological properties [23]. Moreover, it was also demonstrated that those compounds might serve as black toning agents for laminated photographs or as starting materials for the synthesis of thiazolo [3,2-b] [1,2,4]triazepines, which are supposed to have immunomodulating activities [24].…”

Formation of pyrazol‐1,3,4‐thiadiazoles through 1,3‐dipolar cycloadditions of 3‐thioxo‐[1,2,4]‐triazepin‐5‐one with nitrilimines: an experimental and computational study

“…14,15 They are reported as excellent ligands with transition metals inducing a large application in organometallic chemistry. 16,17 In the context of our current interest in the synthesis of novel heterocyclic compounds, [18][19][20][21][22] susceptible to have biological activity, we have now studied the 1,3-dipolar cycloaddition (13DC) reaction between 6-dimethylaminomethylene-3-thioxo-[1,2,4]-triazepin-5-one 1 and C,N-disubstituted nitrilimines 2a-f (Scheme 1), which were generated in situ from the appropriate precursors and triethylamine. However, we have found that along the purification of reaction mixture by column chromatography, the corresponding spirocycloadducts 3a-f were transformed into the bicyclic compounds 4a-f and 5a-f. Herein, we present the experimental results of the title reaction together with a theoretical study providing an explanation for the formation of the two new bicyclic compounds.…”