50 JOUKNAL OF THE MlTCIIELL, SoCIETY \_Octol)er 



juglone is very readily oxidized, even by iron chloride, to juglone, 

 the subject of this paper. The oxidation affects the hydroxyl groups 

 at positions 1 and 4, removes the hydrogen atoms and thus produces 

 a quinone (II). Juglone is therefore 5-hydroxy-l-4-naphthoquinone. 



HISTORY OF JUGLONE. 



Juglone was first mentioned by Vogel and Keischauer^, who obtain- 

 ed it from fresh walnut hulls. It is next referred to by Phipson^ who 

 called it regianin. His product was evidently not pure. In 1877 

 Griessmayer^ published Reischauer's notes on juglone (the first 

 appearance of this name) giving an analysis of this compound and 

 its copper salt. The names given above are derived from the botanical 

 name of the walnut tree, Juglans regia. Bernthsen* gave a number 

 of reasons for believing it to be an hydroxynaphthoquinone. Bernth- 

 sen and Semper^ extracted 150 kilograms of ripe walnut hulls with 

 ether and obtained a yield of 150 grams or 0.1% of pure juglone. 

 By the action of nitric acid they obtained juglonic acid or dinitro- 

 hydroxyphthalic acid, showing that the hydroxyl group in juglone is 

 in the benzene ring. Mylius^ fused juglone with potash and obtained 

 m-hydroxybenzoic acid and salicylic acid. Bernthsen and Semper^ 

 prepared the dioxime, having made the monoxime earlier. These 

 reactions established the constitution of juglone as being 5-hydroxy-l, 

 4-naplithoquinone. Finally Bernthsen and Semper^ synthesized 

 juglone by oxidizing 1, 5-dihydroxynaphthalene with chromic acid, 

 obtaining a yield of 30-40 per cent, a record which I have never 

 been able to make. I have varied the process in many ways and never 

 get more than 16 per cent. The acetyl derivative and the monoxime 

 of the synthesized juglone were found to be identical with those 

 obtained from the natural juglone. 



iBuchner Neues Repert. fiir Pharm. 5: 10&. 1856; L' Institut 1857, 71. 



2Compt. rendus., 69: 1372. 1869. 



3Ber.desdeutsch.Chem.Ges., 10: 1542. 1877. 



4Ber.d.d.Chem.Ges. 17: 1945. 1884. 



5Ber.d.d.Chem.Ges., 18: 203. 1885. 



6Ber.d.d.Chem.Ges., 18: 463. 1885. 



TBer.d.d.Chem.Ges., 19: 164. 1886. 



SBer.d.d.Chem.Ges., 20: 934. 1887. 



