NON  Furoxane . such as furfuracrolein, C4H3O•CH:CH•CHO, and furfuracetone, C4H3O•CH:CH•CO•CH3 . With alcoholic

potassium cyanide it changes to furoin, C4H3O.CHOH•CO•C4H3O, which can be oxidized to furil, C4H3O•CO•CO•C4H30, whilst alcoholic potash converts it into furfuryl alcohol . With fatty acids and acid anhydrides it gives the " Perkin " reaction (see CINNAMIC ACID) . Furfurol is shown to have its aldehydic group in the a position, by conversion into furfurpropionic acid, C4H3O•CH2•CH2•CO2H, which on oxidation by bromine water and subsequent reduction of the oxidized product is converted into n-pimelic acid, HO2C(CH2)5CO2H . Furfurol in minute quantities can be detected by the red colour it forms with a solution of aniline acetate . Furfurane- aa'- dicarboxylic acid or dehydromucic acid, C4H20(CO2H)2, is formed when mucic acid is heated with hydrochloric acid at too° C . On being heated, it loses carbon dioxide and gives pyromucic acid . By digesting acetoacetic ester with sodium succinate and acetic anhydride, methronic acid, C8H805, is obtained; for the constitution of this acid, see L . Knorr, Ber., 1889, 22, p . 152, and R . Fittig, Ann., 1889, 250, p .

166 . Di- and tetrahydrofurfurane compounds are also known (see A . Lipp, Ber., 1889, 22, p . 1196; W . H . Perkin, junr . Journ . Chem .

Soc., 1890, 57, p . 944; and S . Ruhemann, ibid., 1896, 69, p . 1383) .