54 INDIAN MEDICINAL PLANTS. 



Pikrotoxinin, 15 H 16 O 6 , is best obtained from pikrotoxm by bromiiiating 

 the latter, when- in hot aqueous solution, with a slight excess of bromine 

 water, and then, by means of zinc dust and acetic acid, removing the bromine 

 from the monobromopikrotoxinin, which crystallises out ; it crystallises from 

 hot water in colourless, anhydrous needles, but from cold aqueous solutions in 

 rhombic, plates containing lff 2 0, melts at 200-201°, is readily soluble in all 

 the usual solvents on warming, and also in cold alcohol or chloroform ; it is 

 also soluble in alkalies, but is not reprecipitated on the addition of acids. 

 Sulphuric acid develops an intense orange red coloration, and when hydro- 

 gen chloride is led into an ethereal solution of the compound, polymerisa- 

 tion occurs, and pikrotoxide, melting ,at 308-310°, is formed. Aqueous 

 solutions reduce ammoniaeal silver nitrate in the cold, but it contains neither 

 an aldehydic nor a ketonic group. It has an extremely bitter taste, and is 

 the active principle of pikrotoxm ; its specific rotatory power [a]D— — 5*85°, 



BromopikrotoxiniD, C 15 H 15 BrO ff . which is most readily obtained by adding 

 bromine water to a hot, nearly saturated;, aqueous solution of pikrotoxinin 

 until the solution remains permanently yellow, may be purified by recrystal- 

 lisation from absolute alcohol ; it separates in glistening needles, melts at 

 259-260° (Schmidt gives 250-255° ; Paterno and Oglialoro give 240-250°), and 

 has[a]17/D= -132'5°. 



Chloropikrotoxinin crystallises from alcohol in a mixture of needles and 

 plates, melting at 272°. 



Iodopikrotoxiniu, obtained by the action of iodic acid and a solution of 

 iodine in potassium iodide C 15 H 14: O -Ac 2 , as it can readily be obtained by the 

 action of acetic chloride on pikrotoxinin ; it sublimes in slender needles 

 melting at 254° — 255,° and forms an unstable compound with bromine. 



Pikrotin, C 15 H 13 7 , is best obtained from the filtrate from bromopikrotox- 

 inin, part separating out on cooling, whilst the remainder may be obtained 

 by evaporation ; it can be purified by several extractions with small 

 quantities of hot chloroform, followed by recrystallisationfrom water ; it forms 

 small, felted needles, or thick, rhombic prisms, melting at 248-250°, is readily 

 soluble in absolute alcohol or acetic acid, but only sparingly in ether, 

 chloroform, or benzene. Its specific rotatory power [o]D=— 64'7°, and it 

 reduces Fehling's solution, etc., but only on warming. Its molecular formula 

 has been determined by molecular weight determinations and by the analyses 

 of its benzoyl and acetyl derivatives. 



lienzoylpikrotin, C 1& H 17 7 BZ, crystallises from absolute alcohol in colour- 

 less needles, melts at 236°, and is readily soluble in chloroform, sparingly in 

 ether or alcohol. 



Libenzoylpikrotin, obtained when pikrotin (1 mol.) is heated with benzoic 

 chloride (3 mols.) at 190°, crystallises from alcohol in needles melting on a 

 hot aqueous solution of pikrotoxinin, crystallises from alcohol in colourless 

 needles and melts at 198-199°. 



L romopikrotoxic acid, C 14 H 10 -BrO 5 *COOH-fH 2 O, is obtained when 10 percent, 

 potassium hydroxide solution is slowly added to finely divided bromopikro- 

 toxinin suspended in 10 times its weight of boiling water, until all has dis- 

 solved ; on the addition of hydrochloric acid, the acid crystallises out in 

 colourless needles, melting at 245-246° ; it has no bitter taste, and is optically 



