3-Amino--tetrazines from the thermal decomposition of 4-amino-3-azido--triazoles

Takimoto, H. H.; Denault, G. C.

doi:10.1016/s0040-4039(01)84207-6

Cited by 27 publications

(12 citation statements)

References 15 publications

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“…Takimoto and Denault described the formation of 3-amino-s -tetrazines from the thermal decomposition of 1-amino-3-azido-s-triazoles (14). 5 The cyclization of a-hydrazono oximes (15) to 1,2,3-triazoles (eq 816 provides an analogy for the cyclization of 8 to 2. The formation of 3e must then be understood via oxidation to the N-nitrene (16) followed by a diazene-hydrazone rearrangement.8…”

Section: Discussionmentioning

confidence: 99%

Manganese dioxide oxidation of aryl 1,2-diaminoimidazoles

Nakajima¹,

Hisada²,

Anselme³

1978

J. Org. Chem.

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The oxidation of aryl 1,2-diaminoimidazoles (1) with manganese dioxide to 1,2,3-triazoles (2) and/or 3-amino-1,2,d-triazoles (3) is described. Aroyldiazomethanes (4), benzonitriles ( 5 ) , and acetophenones (6) were minor products of this oxidation. The formation of 2 and 3 from the monoaryl imidazoles (la-c) is viewed as proceeding via the formation of the C-nitrenes (or nitrenoids) which open to the a-hydrazono-N-cyanoimines (81, followed by cyclization to either 2 or 3. The a-hydrazono-N-cyanoimines (8) can also account for the formation of 4 and 5, while fragmentation of the N-nitrenes would explain the presence of the acetophenones (6). The mechanism of the oxidation of 4,5-diphenyl-1,2-diaminoimidazole (Id) and 1,2-diaminobenzimidazole ( l e ) is also discussed.The manganese dioxide oxidation of 4-phenyl-1,2-diaminoimidazole (la) to 4(5)-phenyl-1,2,3-triazole (2a) and 3-amino-5-phenyl-1,2,4-triazine (3a) has been recently described in a communication.2a The formation of 2a and 3a was 3d 2d I 3 H I NH, 1 2 -+ .b..rCOCHN=h i-ArC-4-N + ArCOCH, (1) 4 5 6 a, R = H; Ar = Ph b, R = H; Ar = p-BrC,H, c , R = H ; Ar = p-CH,OC,H, d , R = Ar = Ph e , R, Ar = c rationalized via formation of the C-nitrene (or nitrenoid) 7a which could then undergo ring opening to the a-hydrazono-N-cyanoimine (8) thence to the observed products 2a and 3a.Ar CN .4r

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Section: Discussionmentioning

confidence: 99%

Manganese dioxide oxidation of aryl 1,2-diaminoimidazoles

Nakajima¹,

Hisada²,

Anselme³

1978

J. Org. Chem.

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“…Most of the compounds prepared by this method were not described in the literature before. The already known compounds 1 and 10 were prepared according to published routes (2) and their physical data compared with those of the compounds obtained in this study. They proved to be identical.…”

Section: -(Alkyl)amino-3-aryl(alkyl)-1245-tetrazinesmentioning

confidence: 99%

A new synthesis of 6‐(alkyl)amino‐3‐aryl(alkyl)‐1,2,4,5‐tetrazines

Counotte-Potman

Plas

1981

Journal of Heterocyclic Chem

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“…In a seminal publication, such opening reactions have been classified by Herges as proceeding via coarctate transition states. [2] The resulting formal ene-enenitriles have cyclized further to interesting heterocycles, for example, in the case of the high-yielding conversion of Namino-2-azido-1,3,4-triazoles into 3-amino-1,2,4,5-tetrazines, [3] the reaction of 1-amino-2-azidoimidazoles into a mixture of 1,2,3-triazoles and 3-amino-1,2,4-triazines, [4] or the irradiation of 3-azidopyrazole-4-carbaldehydes into a mixture of 4-cyanopyrazoles and 4-cyano-3-azofurans. [5] …”

Section: Introductionmentioning

confidence: 99%

Photochemical Arylation of Brønsted Acids with 2‐Azidobenzimidazole

2011

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Irradiation of N‐benzylated 2‐azidobenzimidazoles at 300 nm in the presence of an excess amount of carboxylic acids results in a novel regioselective synthesis of 2‐amino‐6‐oxybenzimidazoles in isolated yields of 60–70 %. It is also possible to regioselectively introduce 6‐bromo, 6‐chloro, and 6‐triflyloxy groups. Irradiation in dichloromethane in the absence of external nucleophiles revealed that after loss of nitrogen, the benzimidazolylnitrene probably undergoes coarctate ring opening to an N‐cyano diaza‐o‐xylylene intermediate.

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3-Amino--tetrazines from the thermal decomposition of 4-amino-3-azido--triazoles

Cited by 27 publications

References 15 publications

Manganese dioxide oxidation of aryl 1,2-diaminoimidazoles

Manganese dioxide oxidation of aryl 1,2-diaminoimidazoles

A new synthesis of 6‐(alkyl)amino‐3‐aryl(alkyl)‐1,2,4,5‐tetrazines

Photochemical Arylation of Brønsted Acids with 2‐Azidobenzimidazole

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