Phosphoric Acid → Ethyl 6-chloro-1-benzofuran-7-carboxylate

Participants

Reaction Steps

Using analogous procedures to those described in the third paragraph of the portion of Note [6] in Example 2 that is concerned with the preparation of 7-amino-5-fluorobenzofuran, ethyl 3-allyl-6-chloro-2-hydroxybenzoate was reacted with ozone and the resultant product, 2-(4-chloro-3-ethoxycarbonyl-2-hydroxyphenyl)acetaldehyde, was treated with 85% phosphoric acid to give ethyl 6-chlorobenzofuran-7-carboxylate (5.9 g); NMR Spectrum: (DMSOd6) 1.35 (t, 3H), 4.45 (q, 2H), 7.10 (d, 1H), 7.45 (d, 1H), 7.85 (d, 1H), 8.15 (d, 1H).

Provenance & Evidence