73876-43-4Relevant academic research and scientific papers
Photolysis and Pyrolysis of Phenyltetrazoles: Formation of Phenylcarbodiimide, N-Phenylnitrile Imine, Phenylnitrene, Indazole, and Fulvenallene
Zhao, Xiaofang,Liu, Qian,Feng, Ruijuan,Zeng, Xiaoqing,Wentrup, Curt
, p. 6945 - 6950 (2019)
Photolysis of 1-phenyltetrazole 2b at either 193 or 266 nm in a Ne matrix as well as flash vacuum pyrolysis (FVP) of the same compound with isolation of the products in Ne matrix generate phenylcarbodiimide PhN=C=NH 6 very efficiently as the principal product in an almost pure state. Minor amounts of phenyl azide 8 and 1-azacyclohepta-1,2,4,6-tetraene 10, the product of ring expansion of phenylnitrene, are also formed, and the amounts of both substances increase as a function of photolysis time. The photolysis of 2-phenyltetrazole 1b in a Ne matrix at 266 nm for 0.5 min generates the allenic N-phenylnitrile imine PhN=N(+)=CH(–) 3b, absorbing strongly and cleanly at 2021 cm–1 in the IR spectrum. At longer photolysis times peaks ascribed to phenyl azide, phenylnitrene, 1-azacycloheptatetraene, and phenylcarbodiimide 6 become prominent. FVP of 2-phenyltetrazole yields indazole 15 as the major product together with a small amount of phenylcarbodiimide 6. Indazole formation is ascribed to cyclization of the nitrile imine in the ground state. It is not formed on FVP of 1-phenyltetrazole in agreement with the computational result that the thermodynamically most favourable path for rearrangement of the putative N-phenylimidoylnitrene 5b yields phenylcarbodiimide 6 rather than phenylnitrile imine 3b. Further pyrolysis of indazole affords a minor yield of fulvenallene 18.
