COUMARONES or Benzofurfuranes, organic compounds containing the ring system
This ring system may be synthesized in many different ways, the chief methods employed being as follows: by the action of hot alcoholic potash on α-bromcoumarin (R. Fittig, Ann., 1883, 216, p. 162),
from sodium salts of phenols and α-chloracetoacetic ester (A. Hantzsch, Ber., 1886, 19, p. 1292),
or from ortho-oxyaldehydes by condensation with ketones (S. Kostanecki and J. Tambor, Ber., 1896, 29, p. 237), or with chloracetic acid (A. Rossing, Ber., 1884, 17, p. 3000),
The parent substance coumarone, C8H6O, is also obtained by heating ω-chlor-ortho-oxystyrol with concentrated potash solution (G. Komppa, Ber., 1893, 26. p. 2971),