Synthesis of 1-(2-benzofurancarbonyl)azulenes using 1-(bromoacetyl)azulenes as new building blocks
作者:Satoko Yamashiro、Kimiaki Imafuku
DOI:10.1002/jhet.5570390411
日期:2002.7
afford 1-acetyl-3-bromoazulene (3) and 3-bromo-1-(bromoacetyl)azulene (4). In a similar manner, 3-methyl-, 3-ethyl-, 3-propyl-, and 3-methoxycarbonyl-substituted 1-acetylazulenes 2a-d gave the corresponding 3-substituted 1-(bromoacetyl)azulenes 5a-d as major products and 1-(dibromoacetyl)azulenes 6a-d as minor ones. The 1-(bromoacetyl)azulenes 5a-d are useful as new building blocks. Compounds 5a-d reacted
with sodium monobromoisocyanurate (SMBI) (1) to give 3‐bromo‐substituted azulenes 5 and 6, respectively. The brominations in dichloromethane gave the brominated products in low yields, while the reactions in dichloromethane–water gave the products in high yields. This indicates that SMBI (1) was hydrolyzed in the presence of water to generate hypobromic acid, which accelerated the bromination as a
pulse voltammetry (DPV). The synthesis of 1,2′-biazulenes was established by palladium-catalyzed homocoupling reactions of the corresponding 1-haloazulenes in the presence of ferrocene. The optical properties of the novel 1,2′-biazulenes were investigated by UV/Vis spectroscopy and theoretical calculations. The redoxbehaviors of 1,2′-biazulenes were also examined by cyclic voltammetry (CV) and differential