140111-27-9

Upstream product

• 142362-68-3 1,4,6,9-tetramethyl-9-phenyl-1,2,3,4,6,7,8-heptaazaspiro[4.4]nona-2,7-diene 
• 139688-73-6 4,5-Dihydro-1,4-dimethyl-5-(1-phenylethyliden)-1H-tetrazol 

Relevant academic research and scientific papers

Thermolysis of 1,2,3,4,6,7,8-Heptaazaspironona-2,7-dienes, Cycloadducts of Azides and 5-Alkylidene-4,5-dihydro-1H-tetrazoles

On thermolysis of the title compounds at 20 - 150 deg C, three modes of ring cleavage are observed, viz. cycloreversion of the triazole (path A) or the tetrazole ring (path B) to azide 2 and the corresponding dipolarophile, or extrusion of molecular nitrogen from the triazole ring with concomitant 1,2 shift of a nitrogen atom to afford an iminotetrahydrotetrazine 31 (path C).An equilibrium between cycloaddition and cycloreversion (path A) is established starting from the heptaazaspirononadienes 4.Irreversible cycloreversion of the tetrazole ring (path B) is observed on thermolysis of 6, yielding azide 2 and iminodihydrotriazoles 7.Path A and B compete in the thermolysis of 6e affording, besides methyl azide (2a), 5c and 7e.Because path A is reversible, the former disappears again while the latter extrudes molecular nitrogen to yield the iminoaziridines (E)- and (Z)-12 which decompose to the imine 13 and methyl isocyanide (14).Competition between path A and B is also observed on thermolysis of 15 and, probably, the diphenyl compound 21 as well.The latter affords a complex mixture comprising the iminodihydrotriazole 16, the iminoaziridines 18 and 23, the cycloreversion products 14 and 19 of 18, and the 2-aminoindole 26 which is formed by isomerization of 18 and/or 23.None of the cycloreversion reactions, but only extrusion of molecular nitrogen and formation of 31 (path C) are observed on thermolysis of the nitrophenyl spirocycles 29.The course of the thermolyses is mainly governed by the size and the electronic character of the substituent that stems from the azide used in the formation of the title compounds. Key words: Cycloaddition, 1,3-dipolar / Cycloaddition and cycloreversion, equilibrium by / Cycloreversion / Thermolysis / Spironona-2,7-dienes, 1,2,3,4,6,7,8-heptaaza- / 1H-Tetrazoles, 5-alkylidene-4,5-dihydro- / 1H-1,2,3-Triazoles, 4,5-dihydro-5-imino- / Aziridines, imino- / 1,2,3,4-Tetrazines, 5-imino-1,4,5,6-tetrahydro-

Photoextrusion of Molecular Nitrogen from 5-Alkylidene-4,5-dihydro-1H-tetrazoles Substituted by Vinyl or Phenyl Groups. (E)-Aziridinimines and Novel Products

Direct irradiation of deuterated hydrocarbon solutions of the alkylidenehydrotetrazoles 11 affords quantitative yields of the aziridinimines (E)- and (Z)-12, besides molecular nitrogen, with (E)/(Z) ratios ranging from 95:5 (12e, -40 deg C) to >99: photocycloreversion into the corresponding isocyanides 16 and imines 17, which is induced by selective irradiations with light of shorter wavelengths.Photolysis of the alkenylidenedihydrotetrazole 18c at -40 deg C affords the 2-imino-3-vinylaziridine 20c which decomposes at higher temperatures.Irradiation of 18c at 20 deg C or partial photolysis at -40 deg C followed by warming to 20 deg C furnishes the spirocyclic product 19c.The analogous products 19a and b are obtained from 18a and b.The vinyl compound 19a very slowly isomerizes to the ethylidene compound 23 by a proton 1,3-shift.The spirocyclic structures 19 and 23 are based on mass and NMR spectra including (1)H,(1)H and (13)C,(1)H COSY and extensive (1)H,(1)H decoupling experiments.The formation of the spirocycles 19 is interpreted in terms of a photoextrusion of molecular nitrogen from 18 to afford 3-vinylaziridinimines 20 which, at higher temperatures, rearrange to the 1,3-diazabutadienes 24 by a hydrogen homo- or -shift. Cycloaddition of 24 to unchanged 18 eventually yields the spirocycles 19. Key Words: 1H-Tetrazoles, 5-alkylidene-4,5-dihydro- / Aziridines, 2-imino- / 1,3-Diazabutadienes / Spirodeca-2,7-dienes, 1,2,3,4,6,8-hexaaza- / Photoextrusion of molecular nitrogen / Photocycloreversion / Hydrogen shift, homo- and homo- / Cycloaddition