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Synthesis of 1‐(2‐benzofurancarbonyl)azulenes using 1‐(bromoacetyl)azulenes as new building blocks
Author(s) -
Yamashiro Satoko,
Imafuku Kimiaki
Publication year - 2002
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570390411
Subject(s) - azulene , chemistry , chloroform , yield (engineering) , stereochemistry , medicinal chemistry , organic chemistry , metallurgy , materials science
1‐Acetylazulene ( 1 ) was treated with trimethylphenylammonium tribromide in refluxing chloroform to 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 salicylaldehydes 9a‐g to yield twenty‐eight cyclized products, 1‐(2‐benzofurancarbonyl)azu‐lenes 11aa‐dg , via 1‐phenoxyacetylazulenes 10aa‐dg.