348 Journal of Agricultural Research voi. xni, no. 7 



GossYPETiN. — By the hydrolysis of gossypitrin Perkin obtained 

 gossypetin and a sugar identified as dextrose. Gossypetin has also 

 been found as a glucosid in Hibiscus sabdarifja (2). It crystallizes in 

 yellow needles melting at 311° to 313° C. They are slightly soluble in 

 water, but are easily soluble in alcohol. Acetylgossypetin crystallizes 

 from a mixture of alcohol and acetic acid in colorless needles melting 

 at 228° to 230° C. These are readily soluble in acetic acid, but are 

 somewhat sparingly soluble in alcohol. 



EXPERIMENTAL WORK 



ISOI/ATION OF QUERCIMERITRIN FROM THE) PETALS 



Quercimeritrin was isolated by Perkin's method (5), which was modi- 

 fied by omitting the use of lead acetate and was then employed in the 

 following manner: An alcoholic extract from 1,214 gm. of air-dried, 

 powdered petals was evaporated to a volume of about one and one-half 

 liters. The deep purple-red solution was filtered from the dark material 

 which had separated. This residue was warmed with water and filtered. 

 On standing, an amorphous brick-red substance separated. This was 

 filtered off by suction, boiled in absolute alcohol, and again filtered hot. 

 On cooling, the yellow glucosid deposited in microcrystalline form, 

 melting at 243° C. When mixed with known material obtained from 

 petals by Perkin's original method, no lowering of the melting point 

 was observed. 



ISOLATION OF ISOQUERCITRIN FROM THE PETALS 



In another experiment the alcoholic solution was evaporated to a 

 small volume, and water was added. The mixture was then evaporated 

 until most of the alcohol was gone. After extracting the aqueous solu- 

 tion with ether, neutral lead acetate was added. The heavy, dull- 

 yellow precipitate produced by this reagent was filtered off. A thin 

 paste was then made with water, and the lead removed by passing 

 hydrogen sulphid through the mixture. After filtering, the filtrate was 

 evaporated somewhat and allowed to stand in a vacuum desiccator for 

 several days, when small greenish-yellow needles separated. On recrys- 

 tallization from dilute methyl alcohol several times, the product finally 

 melted at 247° C. The substance was undoubtedly quercimeritrin. 



The filtrate from the lead acetate precipitation was treated with basic 

 lead acetate, which produced another heavy dull-yellow precipitate. 

 The lead was removed from this precipitate as in the pre\dous case, and 

 the solution was slowly evaporated over sulphuric acid in a vacuum 

 desiccator. From this solution there was obtained by fractional crystalli- 

 zations more quercimeritrin, and from the mother liquors a crystalline 

 substance melting, after purification from pyridin and water, at 219° C. 

 Hydrolysis of this compound yielded quercetin. It was consequently 

 identified as isoquercitrin. 



