Coumarones

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),

It is a colourless liquid which boils at 171-172° C. and is readily volatile in steam, but is insoluble in water and in potash solution. Concentrated acids convert it into a resin. When heated with sodium and absolute alcohol, it is converted into hydrocoumarone, C8H8O, and ethyl phenol.