Origin and Production. The root bark of Paeonia Moutan, Sims (family Ranunculaceae), a drug that is used extensively in japan and China, contains on its inner surface as well as on fracture surfaces small white crystals of paeonol that can be isolated by distillation with water vapor or, better still, by extraction with ether. The crude oil is purified by first shaking out its ethereal solution with soda solution which takes up the impurities only; then by removing the paeonol by means of aqueous sodium hydroxide and separating it by means of sulphuric acid.
1) Pharm. Rundsch. (New York' 13 (1S95), 89.
2) Report of Schimmel & Co. April 1891, 61.
3) These, Montpellier 1901.
4) Apotheker Ztg. M (1901), 281.
According to W. Will1) the yield amounts to 3 to 4 p.c, whereas Schimmel & Co. could obtain but 0,4 p.c. of oil upon distillation of the root with water vapor.
Properties. The oil obtained by distillation consists, at ordinary temperature, of a yellowish, solid mass, saturated with a brown liquid. It melts at about 40°; d15o (super-cooled) 1,1502; aD inactive; nD80o (super-cooled) 1,56460; A. V. 12,6; E. V. 24,5; E. V. after acetylation 220,7; not completely soluble in 10 vol. of 70 p.c. alcohol, soluble in 1 vol. and more of 80 p.c. alcohol.
Composition. Paeonol was first isolated by Martin and Jagi2). Basing their conclusions on an elementary analysis and an examination of its calcium compound, they regarded it as a fatty acid closely related to caprinic acid. According to W. IS. Nagai3), paeonol possesses an aromatic odor, crystallizes in needles, melts at 50°, and has the composition C9H10O34). It is but sparingly soluble in cold water, readily so in hot water, alcohol, ether, benzene, chloroform and carbon disulphide. Ferric chloride colors the aqueous as well as the alcoholic solution a red-violet. Aqueous caustic alkalies dissolve paeonol forming well crystallizable salts therewith.
As ascertained by Nagai, the constitution of paeonol is expresOch3  sed as o-methoxy-o-hydroxyphenylmethyl ketone: C6H3OH  needles, the phenyl hydrazone in needles that are faintly yellow in color and melt at 170°.
Coch.W When fused with potassium hydroxide or when boiled with hydrogen iodide, resacetophenone C6H3OH. OH Coch3  melting at 142°, results. Acetylpaeonol, m. p. 46,5°, is oxidized by means of permanganate to p-methoxysalicylic acid C6H3OCH3  •OHCOOH . The oxime of paeonol crystallizes in fine Tahara1) prepared paeonol synthetically by methylating resacetophenone.
1) Berl. Berichte 19 (1886), 1776.
2) Arch, der Pharm. 218 (1878), 335.
3) Berl. Berichte 24 (1891), 2847.
4) Tiemann, Berl. Berichte 24 (1891) 2854, found the melting point of pure paeonol at 48°. Other derivatives of paeonol are described: Ibidem 25 (1892), 1284 and 29 (1896), 1754.