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Investigations of substituted benzofuran‐3‐carboxylates, benzo[1,2‐ b :4,5‐ b ']difurans and benzo[1,2‐ b :4,3‐ b ']difurans
Author(s) -
McPherson H. L.,
Ponder B. W.
Publication year - 1978
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.5570150110
Subject(s) - chemistry , benzofuran , stereochemistry , ethyl acetoacetate , medicinal chemistry , organic chemistry , catalysis
The Michael addition of ethyl acetoacetate to benzoquinone, toluquinone, and chlorobenzo‐quinone leads to formation of substituted 5‐hydroxybenzofuran‐3‐earboxylates and linear benzo‐[1,2‐ b :4,5‐ b ']difurans. The previously reported structural proof for the benzodifurans obtained from chlorobenzoquinone and toluquinone, although correct in the conclusion, is shown to be invalid. Proof of the linear benzodifuran structures was obtained by comparison of the uv spectra with authentic angular benzo[1,2‐ b :4,3‐ b ']difurans.