Unanticipated formation of a novel octaazacyclo-decane ring upon oxidation of a 1,1-bis-urazole

作者：Breton Gary W^*; Martin Kenneth L

来源：Acta Crystallographica Section C-Structural Chemistry, 2018, 74(5): 558-+.

DOI：10.1107/S2053229618005211

• tetrahydrotetrazole
• tetrazole
• tetrazolidine
• persistent radicals
• urazole radicals
• radical dimer
• crystal structure

Tetrahydrotetrazoles are a little-explored class of five-membered heterocycles with four contiguous singly-bonded N atoms. Recent work in our labs has demonstrated that urazole radicals are amenable to N-N bond formation via radical combination to form such a chain of four N atoms. Previously described 1,1-bis-urazole compounds appeared to be convenient precursors to the target tetrazoles via their oxidation to intermediate urazole diradicals, which upon N-N bond formation would complete the tetrazole framework. While oxidation proceeded smoothly, the novel 10-membered octaaza heterocycle 7,7,18,18-tetraacetyl-4,10,15,21-tetraphenyl-1,2,4,6,8,10,12,13,15,17,19,21-dodeca-azapentacyclo[17.3.0.0(2,6).0(8,12).0(13,17)]docosan-3,5,9,11,14,16,20,22-octone, C42H32N12O12, was obtained (36% yield) instead of the expected tetrazole product, as confirmed by X-ray crystallography. Calculations at the (U) B3LYP/6-311G(d,p) level of theory suggest that the desired tetrazoles have weak N-N bonds connecting the two urazole units.

• 出版日期2018-5