08 



DICTIONARY OV THE ACTIVE PRINCH'LKS OF PLANTS. 



cardiac stimulant. Combines only with strong'acids ; salts only in acid 

 solution — the compounds with acids not being very stable. 



Solubility (authorities differ to some extent) of anhydrous Caffeine : 

 1 in '.I.S cold water, 1 in 1(1 hot, 1 in 117 cold alcohol, 1 in 11(4 cold ether 

 (less readily in absolute ether) ; also in amyl alcohol, chloroform and 

 benzene ; scarcely in carbon bisulphide or petroleum ether. 

 1; Removed by benzene and chloroform from alkaline and acid solutions. 

 Precipitants (precipitation imperfect) : 

 [Not alkaline hydrates. 

 „ ., carbonates. 



„ ammonia.] 

 [Tannic acid cloud ; insoluble in hydrochloric acid cold, but dis- 

 solved on warming.] 

 [Picric acid, not dilute.] 

 [Not ferric chloride.] 

 [Platinum chloride only in very strong solutions, gradual crystalline 



pp. .soluble in about 20 parts cold water.] 

 [Gold chloride, after some hours, yellow crystalline ]ip.] 

 [Fehling's solution, not reduced if pure.] 

 [Not .silver potassium cyanide. 

 „ potassium bichromate, 1 in 3,000. 

 „ chromic acid 5 per cent, solution.] 

 Phosphomolybdic acid, yellow. 

 [Not phospho-antimonic acid.] 

 [lodo-potassic iodide, dirty brown, but not dilute.] 

 Bismuth-potassic iodide, 1 in 3,000. 

 [Not cadmium-potassic iodide. 

 „ zinc-potassic iodide. 

 „ mercuric- potassic iodide.] 

 jVIercuric chloride, crystalline needles ; 1 in 1,000 after a time. 

 Colour tests (mostly negative) : 



[Concentrated sulphuric acid, colourless (twenty-four hours). 

 „ ,. ., with sugar, no effect. 



„ „ „ with potass, bichromate, no effect. 



,, ,, „ with nitric acid, colourless. 



Nitre added after ten to fifteen hour.s' solution in sulphuric acid, 



colourless. ] 

 Concentrated nitric acid, colourless ; but on evaporation over water- 

 bath and cautious addition of ammonia, purple (murexide test). 

 This reaction is more sensitive when Chlorine or Bromine water is 

 substituted for the nitric acid, avoiding excess. 



[Concentrated hydrochloric acid, no effect. 

 Fruhde's solution, colourless.] 



(6) CAFFEIDINE. from Caffeine by boiling with Baryta water; CVH,._.N40 

 (Caffeine+H.jO — CO.J ; crystals are obtainable; M.P. 94'" (Wernecke). 

 The free base readily decomposes into Ammonia, Methylamine, and 

 Cholestrophane. Salts crystalline. 



(<■) THEOPHYLLINE. 



CVHsN.Oo+H.O.orCO } J|^h — C^:N- } ^O+HJ). 

 Crystalline ; becomes anhydrous at 110 . Closely resembles Theinc. to 

 which it may be converted by methylation. 



Soluble in water and alcohol. 



Ammonia dissolves readily. 



Chlorine water gives on evaporation, a bright red, changing to violet 

 with ammonia. 



(rf) THEOBROMINE, 



C-H8NiO„,orCH3N-CH 



I : 



COC-NCH., (E.Fischer). 



Ill' 

 HN-C-N-CO. 



Microscopic needles, subliming at 2110° without fusion : neutral reaction, 

 bitter ; similar physiological action to that of Theine ; feebly basic ; salts 

 separate readily into acid and free alkaloid. 



Solubility (authorities differ somewhat) : 1 in 1,C00 parts water at 

 0° C, Ijilu at 2U', 00 boiling ; 1,400 cold alcohol, or about 50 boiling : very 

 difficultly soluble in cold ether (1 in 17,0Uo ?) or in about 600 boiling; 

 with less difficulty in amyl alcohol and chloroform (about 10!) parts of 

 the latter boiling ; scarcely in benzene ; insoluble in petroleum ether. 



Precipitants : 



Alkaline hydrates ) i ui ■ i ■ li 



. - > pp. soluble m e.^icess, rorming salts. 



Ammonia ) ' ' ' = 



[Not neutral lead acetate, but carried down with other matter,-s from 



an aqueous extract of cocoa by ba>:ir lead acetate.] 



[Tannic acid, only cloud in dilute solutions.] 



[Not picric acid.] 



[Not ferric chloride.] 



Platinum chloride, brown flocks, slowly 1 in 3,iX>0. 



Gold chloride, slowly needles. 



