Synthesis of new tricyclic 5,6-dihydro-4<i>H</i>-benzo[<i>b</i>][1,2,4]triazolo[1,5-<i>d</i>][1,4]diazepine derivatives by [3<sup>+</sup> + 2]-cycloaddition/rearrangement reactions
作者:Lin-bo Luan、Zi-jie Song、Zhi-ming Li、Quan-rui Wang
DOI:10.3762/bjoc.14.155
日期:——
Two new series of tricyclic heterocycles, namely 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepinium salts 10 and the related neutral, free bases 13 were synthesized from 4-acetoxy-1-acetyl-4-phenylazo-1,2,3,4-tetrahydroquinolines 8 and nitriles 9 in the presence of aluminium chloride by the [3+ + 2]-cycloaddition reaction of the in situ generated azocarbenium intermediates 14 followed by
两个新的三环杂环系列,即5,6-二氢-4H-苯并[b] [1,2,4]三唑并[1,5-d] [1,4]二氮杂吡啶鎓盐10和相关的中性游离碱在原位的[3 ++ 2]-环加成反应中,在氯化铝存在下,由4-乙酰氧基-1-乙酰基-4-苯基偶氮-1,2,3,4-四氢喹啉8和腈9合成13。生成偶氮碳鎓中间体14,然后进行环扩环重排。在重排反应中,最初形成的螺-三唑鎓加合物16中的苯基取代基经历了[1,2]从C(3)迁移至电子不足的N(2)的过程。这导致环从6元哌啶扩环到7元二氮杂pine,提供了三环1,2,4-三唑稠合的1,4-苯并二氮杂s。