1 



characteristic for fisetin. 



Furthermore, fisetin should give protocatechuic acid 



and phlorogluoinol by fusion with caustic potash under proper 



2 

 conditions • The experiment was carried out as follows: 



2 grams of fisetin ■»» gently heated in a nickel crucible 

 with 6 gracjs of caustic potash dissolved in 6 c.o. water. 

 An inflammable gas, apparently hydrogen^was evolved during 

 the fusion. The pasty mass was dissolved in water, acidified 

 with sulphuric acid, and filtered. The filtrate was shaken 

 out with ether containing one fourth its volume of alcohol. 

 The ether was evaporated and the residue was extracted with 

 warm water and filtered. lead acetate was added to the fil- 

 trate to precipitate protocatechuic acid, while phloroglu- 

 oinol remained in the filtrate from this precipitate. The 

 lead precipitate was suspended in water, decomposed by hydro- 

 gen sulphide, filtered, and evaporated to obtain protocate- 

 chuic acid. That the substan'Je obtained was protocatechuic 

 acid was shown by the following characteristic tests: (l) It 

 gave a greenish brown color with ferric chloride; on addition 

 of one drop of a dilute solution of sodium carbonate, the 

 color became dark blue; on adding more sodium carbonate the 



1. Berichte 19, 1740. 



2. Ibid. 1747; Annftlen, 112, 97. 



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