The synthesis of benzofuroquinolines. V . Some benzofuro[3,2‐ B ]quinoline derivatives

Some benzofuro[3,2‐ b ]quinoline derivatives 1a‐d and 3a were synthesized by condensation of 2‐amino‐benzaldehyde, 2‐aminoacetophenone, 2‐aminobenzophenone, isatin, or 2‐aminobenzoic acid with 3(2 H )‐benzofuranone. The benzofuroquinolinone 3a was also obtained from 2‐aminobenzoic acid and phenoxy‐acetyl chloride in two steps and converted to 10‐chloro derivative 1e . Similarly, some 8‐halobenzofuro[3,2‐ b ]‐quinoline derivatives 1d,e and 3a (X = F, Cl, Br, I) were synthesized from 5‐haloisatin or 2‐amino‐5‐halo‐benzoic acid. And benzofuro[3,2‐ b ]quinolines 1a‐e thus obtained were converted to corresponding N ‐oxides 2 .