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RESINA GUAIAGL 105 



acid ?), 'whichj on addition of concentrated sulphuric acid, turns 

 beautifully red. 



After the extraction of the guaiaconic acid there remain>s a substance 

 insoluble in ether to which the name Guaiac Beta-resin has been 

 applied. It dissolves in alcohol, acetic acid or alkaliS; and is precipitated 

 by ether, benzol, chloroform or carbon bisulphide in brown flocks, the 

 composition of which appears not greatly to differ from that of guaia- 

 conic acid. 



Giiciiacic Acid, C^-^H^^^O^ obtained in 1841 by Thierry from guaiacum 

 wood or from the resin, crystallizes in colourless needles. Hadelich was 

 not able to obtain more than one part from 20,000 of guaiacum resin. 



Hadelich's Guaiac-yellow, the colouring matter of guaiacum resin, 

 first observed by Pelletier, crystallizes in pale yellow quadratic octo- 

 hedra, having a bitter taste. Like the other constituents of the resin, 

 it is not a glucoside. 



The decomposition-products of guaiacum are of peculiar interest. 

 On subjecting the resin to dry distillation in an iron retort and rectify- 

 ing the distillate, Guaiacene (Gicajol of Volckel), C'ffO, passes over 



at US'" C. as a colourless neutral liquid having a burnin^f aromatic 

 taste. H ^ o 



^^ ^^•^° — 210° C, there pass over other products, Giuiiacol, 

 ^H_*.0CH^OH, (methylic ether of pyrocatechin), and Kreosol 

 t- H'.OH(CH'')^ Both are thickish, aromatic, colourless liquids, which 

 pecoine green by caustic alkalis, blue by alkaline earths, and are similar 

 m their chemical relations to eugenic acid. Guaiacol has been prepared 

 rSJ^^^^^^^^y by Gorup-Besanez (18G8) by combining iodide of methyl, 

 '-H I, with pyrocatechin, C'HXOH)'. 



After the removal by distillation of the liquids just described, there 

 sublime upon the further application of heat pearly crystals of Pyro- 

 ymiacin, C^H«0«, an inodorous substance melting at 180° C. The 

 jame compound is obtained together with guaiacol by the dry distiila- 

 U M^ ^"''^^^^•^^i^ acid. Pyroguaiacin is coloured green by ferric 

 cmonde, and blue by warm sulphuric acid. The similar reactions of 

 ine crude resin are probably due to this substance (Hlasiwetz). 



L- 1 ^xi*^^^^ coloured reactions are likewise exhibited by two new acids 



l-il,\ ^^^^^^^'ct^^ and Barth obtained (1S64) in small quantity together 



^ ith traces of fatty volatile acids, by melting purified resin of guaiacum 



J i.tn potassium hydrate. One of them is isomeric with pyrocatechuic 



£ Uses— Guaiacum resin is reputed diaphoretic and alterative. It is 

 requently prescribed in cases of gout and rheumatism. 



Adulteration— The drug is sometimes imported in a very foul con- 

 ition and largely contaminated with impurities arising from a careless 

 "method of collection. 



