Diazo-.beta.-azomethine-v-triazine equilibrium

Temple, Carroll; Kussner, Conrad L.

doi:10.1021/jo01282a034

Cited by 17 publications

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“…[ 72 ] In 1967, Temple also described a diazoimidazole‐triazine equilibrium system, wherein the diazonium salt 24 and 1,2,3‐triazine 25 could be interconverted through modulating the pH value of the mixture (Scheme 5c). [ 73 ]…”

Section: Cyclization and Cycloaddition Reactions For The Constructionmentioning

confidence: 99%

Aryl DiazoniumSalt‐TriggeredCyclization and Cycloaddition Reactions: Past, Present, and Future

et al. 2020

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Aryl diazonium salts occupy a privileged role in synthetic chemistry owing to their ready availability and versatile reactivity. While their applications in accessing diversely functionalized arene derivatives via denitrogenation‐coupling and reduction/addition reactions have been well recognized by practitioners in both academia and industry, recent renaissance in chemical transformations of retaining the key N2‐unit has emerged as a powerful technique to construct various N‐heterocycles. This review covers the history and latest advances in cyclization and cycloaddition reactions using aryl diazonium salts as N2‐annulation synthons. The scope, applications, and opportunities in exploring new chemical space by this sustainable strategy are summarized and discussed.

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Section: Cyclization and Cycloaddition Reactions For The Constructionmentioning

confidence: 99%

Aryl DiazoniumSalt‐TriggeredCyclization and Cycloaddition Reactions: Past, Present, and Future

et al. 2020

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“…Instead of the desired product a high yield of the corresponding amine (15; R' = R2 = NMe,, R3 = NH,) was obtained. Perhaps the desired azide was formed but decomposed in the acetic acid medium, although strongly acidic media are usually necessary for the conversion of azides into amines.,' A change of solvent to ethanol, to avoid acidic conditions, led to a product which analysed for the desired pyrimidotetrazolotriazine (22), but a weak azide band in its i.r. spectrum suggested that the compound ( 22) may be in equilibrium with some of the bicyclic azide from (15; R' = R2 = NMe,, R3 = N3).…”

Section: Pyrimido[45-e]tetrazolo[ 15-c][ 123]triazines-application Of...mentioning

confidence: 99%

Heterocyclic studies. Part 44. Novel tricyclic compounds containing the pyrimido[5,4-d]-1,2,3-triazine system

Clark¹,

Varvounis²,

Bakavoli³

1986

J. Chem. Soc., Perkin Trans. 1

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Treatment of methyl 8-amino-5-chloro-2,3-dihydroimidazo[l,2-c] pyrimidine-7-carboxylate with suitable amines and then nitrous acid gave derivatives (4) of the novel heterocyclic system imidazo[l',2': 1,6]pyrimido[5,4-d] [1,2,3]triazine. The same heterocyclic system in the form of an 8-oxide derivative (5) resulted from nitrous acid treatment of 8-amino-5-methylamino-7-methyl-2,3dihydroimidazo[l,2-c] pyrimidine hydrochloride. In a similar way nitrous acid treatment of suitable imidazo-and pyrimido-[I ,2-alpyrimidine hydrochlorides (6; n = 1 or 2) yielded examples of the new heterocyclic systems imidazo-and pyrimido-[2',1':2,3]pyrimido [5,4-d] [1,2,3]triazine (7; n = 1 or 2).The synthesis of some triazolo-[4,3-a] -and -[1,5-a] -pyrimidines is described and one of these was converted into the 5-morpholino-8-oxide derivative of the novel [1,2,4]triazolo[3',4':2,3] pyrimido-[5,4-4 [1,2,3]triazine system, compound (1 4). Acylation of 4hydrazino-6,8-bisdimethylaminopyrimido[5,4-4-1,2,3-triazine (15; R1 = R2 = NMe,, R3 = NHNH,) and cyclisation of the productsgave derivatives of the new pyrimido[4,5-e] -1,2,4-triazoIo[4,3-c] [1,2,3]triazine system (1 6; R = H, Me, Et, CHCI,, or NH,). However, the benzoylhydrazino compound failed to cyclise in polyphosphoric acid and gave, instead, an oxadiazolyl pyrimidine (18; Scheme 2). The hydrazino compound (15; R1 = R2 = NMe,, R3 = NHNH,) gave a pyrimidotetrazolotriazine (22) on treatment with nitrous acid, and a novel pyrimido[4,5-e] [I ,2,4] triazino[4,3-c] [1,2,3] triazine (23) on treatment with pyruvic acid.An earlier paper in this series described the synthesis of some pyrimido [5,4-d]-1,2,3-triazines and their 3-oxides which were of interest as potential pharmaceuticals. Two new heterocyclic systems, imidazo-and pyrimido-[ 1,2-c]pyrimido[4,5-e][ 1,2,3]triazine were also described. By an unfortunate oversight the earliest example of one of these systems, which was prepared by M. B a k a ~o l i , ~ co-author of this paper, was omitted. The

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“…An indirect synthesis involving ring opening of triazolo [3,4-i]purines or triazolo [5,1-i]purines, which were obtained upon treatment of 6-hydrazinopurine and 6-(1benzylhydrazino)purine with dimethoxymethyl acetate and, more recently, from the reaction of 5-amino-4cyanoimidazoles with triethylorthoformate followed by condensation with hydrazines and acylhydrazines at high temperature. 11 In our research group, 5-amino-4-cyanoformimidoyl imidazoles 1 have been used as versatile precursors for nitrogen heterocycles linked or fused with the imidazole ring. 12 In previous work, imidazoles 1 were reacted with ethyl chloroformate.…”

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confidence: 99%

A Facile One-Pot Synthesis of 3-Imidazolyl 1,2,4-Triazoles and 1,2,4-Oxadiazolones

Dias¹,

Cabral²,

Vila-Chã³

et al. 2010

Synlett

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Diazo-.beta.-azomethine-v-triazine equilibrium

Cited by 17 publications

References 0 publications

Aryl DiazoniumSalt‐TriggeredCyclization and Cycloaddition Reactions: Past, Present, and Future

Aryl DiazoniumSalt‐TriggeredCyclization and Cycloaddition Reactions: Past, Present, and Future

Heterocyclic studies. Part 44. Novel tricyclic compounds containing the pyrimido[5,4-d]-1,2,3-triazine system

A Facile One-Pot Synthesis of 3-Imidazolyl 1,2,4-Triazoles and 1,2,4-Oxadiazolones

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Diazo-.beta.-azomethine-v-triazine equilibrium

Cited by 17 publications

References 0 publications

Aryl DiazoniumSalt‐TriggeredCyclization and Cycloaddition Reactions: Past, Present, and Future

Aryl DiazoniumSalt‐TriggeredCyclization and Cycloaddition Reactions: Past, Present, and Future

Heterocyclic studies. Part 44. Novel tricyclic compounds containing the pyrimido[5,4-d]-1,2,3-triazine system

A Facile One-Pot Synthesis of 3-Imidazolyl 1,2,4-Triazoles and 1,2,4-Oxa­diazolones

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A Facile One-Pot Synthesis of 3-Imidazolyl 1,2,4-Triazoles and 1,2,4-Oxadiazolones