Reactions of 2-(pyrrol-1-yl)benzyl radicals and related species under flash vacuum pyrolysis conditions
作者:J. I. G. Cadogan、Bernard A. J. Clark、Daniel Ford、Ranald J. MacDonald、Andrew D. MacPherson、Hamish McNab、Iain S. Nicolson、David Reed、Craig C. Sommerville
DOI:10.1039/b914965a
日期:——
2-(Pyrrol-1-yl)phenoxyl, aminyl, thiophenoxyl and benzyl radicals 2a–2d, respectively, were generated in the gas-phase under flash vacuum pyrolysis conditions. In all cases except the phenoxyl, cyclisation took place providing acceptable synthetic routes to the fused heterocycles 11, 14 and 15, respectively. Only sigmatropic rearrangement products were isolated, in low yields, from the phenoxyl 2a
在闪蒸真空热解条件下,气相中分别生成了2-(吡咯-1-基)苯氧基,氨基,噻吩氧基和苄基2a-2d。在除苯氧所有情况下,环化发生提供可接受的合成路线的稠合杂环11,14和15分别。从苯氧基2a中仅以低收率分离出σ重排产物。这吡咯并[1,2- a ]苯并咪唑 11独家采用1 H-互变异构体氯仿解决方案。研究了吡咯并[2,1- b ]苯并噻吩14的亲电取代反应,包括质子化,氘交换,Vilsmeier甲酰化以及与乙炔二羧酸二甲酯。在相似的条件下,气相中还会生成2-(2,5-二芳基吡咯-1-基)硫代苯氧基,苯氧基和氨基自由基23a-f。所述thiophenoxyls 23A / b,得到由一次环化产物通过在pyrrrole环自由基的攻击和攻击在所形成的极其复杂的热分解物的混合物本位- ,邻-和间位-芳基环的位置。通过N-芳基的特定σ位移获得了次级热解产物。2,5-二(噻吩-2-基)噻吩氧基基团23c