PIPERONAL (heliotropine, protocatechuic aldehyde methylene

See also:

• ETHER, (C2H5)2O

ether), C8H6O3  , an aromatic aldehyde . It is prepared by oxidizing piperic acid with potassium permanganate (R . Fittig, Ann., 1869, 152, p . 35); by condensing methylene iodide with protocatechuic aldehyde (R . Wegscheider, Monats., 1893, 14, p . 388) ; or by oxidizing isosafrol with chromic acid . It forms long colourless crystals which melt at 370 C. and boil at 263° C . It has an agreeable smell, resembling that of heliotrope, and is much used in perfumery . It is only slightly soluble in cold water, but is readily soluble in alcohol and in ether . When heated with dilute hydrochloric acid to Zoo° C. it yields protocatechuic aldehyde, C7H6O3, and carbon . It readily combines with sodium bisulphite and with various bases (ammonia, aniline, methylamine, &c.) .