A [4 + 3] Annulation Reaction of aza-<i>o</i>-Quinone Methides with Arylcarbohydrazonoyl Chlorides for Synthesis of 2,3-Dihydro-1<i>H</i>-benzo[<i>e</i>][1,2,4]triazepines
An unprecedented [4 + 3] annulation reaction of aza-ortho-quinone methides with arylcarbohydrazonoyl chlorides has been achieved under mild conditions. The annulation underwent a sequential conjugate addition/intramolecular annulation/rearrangement, providing a useful method for the synthesis of biologically interesting 2,3-dihydro-1H-benzo[e][1,2,4]triazepine.
在温和的条件下,已完成了氮杂-邻苯醌甲基化物与芳基羰基肼基甲酰氯的前所未有的[4 + 3]环化反应。进行连续的共轭加成/分子内的成环/重排,为生物上有趣的2,3-二氢-1 H-苯并[ e ] [1,2,4]三氮杂卓合成提供了有用的方法。
We present a PPh3/DDQ-mediated regiospecific selectiveN-functionalization of arylhydrazines with primary benzylic alcohols and aryl carboxylic acids for the synthesis of N1-benzyl arylhydrazines and N2-acyl arylhydrazines, respectively. This metal- and base-free approach features very short reaction times (about 10 min), broad substrate scope, good functional group tolerance, and mild reaction conditions