active [a]D=—62⋅6°. The calcium salt, (C15H16BrO7)2Ca+5H2O, potassium salt, with 2H2O, ammonium salt, and mercurous salt have been prepared.
Picrotoxic acid, C15H18O7, obtained in small amount by the removal of bromine from the bromo-acid by the aid of sodium amalgam in alkaline solution, crystallises from water in needles melting at 229-230°, and has no bitter taste; its aqueous solution has strong reducing properties, and it readily undergoes decomposition in both aqueous and ethereal solution.
The substance obtained by Paternò and Oglialoro by the action of sodium acetate and acetic anhydride on pikrotoxin, and described as an unsaturated acid, is shown to be diacetylpikrotoxinin, at 247-248°. When a large excess of benzoic chloride is employed, no definite product is obtained.
Acetylpikrotin, C15H17O7Ac, crystallises from benzene, alcohol, or acetic acid in glistening plates melting at 244-245°, and is probably identical with the compound described by Paternò and Oglialoro as diacetylpikrotoxinin and melting at 227°. When pikrotin is allowed to remain in contact with acetic chloride for 24 hours at the ordinary temperature, and then heated until complete solution ensues, two compounds are obtained. Anhydrodiacetylpikrotin, C15H14O6Ac2, which is precipitated, on the addition of alcohol, in crystalline masses melting above 300°, and diacetylpikrotin, C15H16O7Ac2, which is obtained as an oil from the alcoholic mother liquor; when it is hot, aqueous solution is allowed to cool, drops of oil separate, which solidify to crystalline needles melting at 207-210°; these contain 2H2O.
Attempts to convert pikrotin into pikrotoxinin by removal of the elements of water have not proved successful.
When warmed with fuming nitric acid, pikrotin yields a nitro-derivative, C15H15O6. No2, anhydronitropikrotin, melting at 260°.J. Ch. S. 1899 A I. 226-227.
42. Coscinium fenestratum, Colebr. H.F.B.I., I. 99.
Syn.:—Menisperum fenestratum, Gaertn.
Vern.:—Jhâr-ki-haldi, or Jhâdi haladi (Dec.); Haldi-gach (B.) Mara-Manjal (Tam.); Mânu pasupu (Tel.); Marada-arishina (Kan.) Veniwel. (Mar.; and Sinhalese).
Habitat:—Western Peninsula, Central and South India. Malacca, Singapore, Ceylon.
A woody climber, bark smooth, young shoots densely but finely yellow-tomentose. Leaves large, 4-8 in., broadly ovate or rounded, suddenly acute, truncate, rounded, subcordate or slightly peltate at base, entire, glabrous above, densely felted, with fine yellow tomentum beneath, strongly 5-7-nerved;