192 JOUKNAL OF THE MiTCHELL SoCIETY [MaVcJl 



We could not confirm the statements in the literature^ that 

 juglone is reduced by sulfurous acid. The best method of re- 

 duction is with zinc and sulfuric acid in the following way. 

 5g Juglone are suspended in a separatory funnel with about 

 50cc ether and an under layer of 2N- sulfuric acid. Zinc dust 

 is added in small portions, followed by vigorous shaking, until 

 the ether layer becomes colorless, though exhibiting a strong 

 greenish fluorescence. After removal of the ether solution, the 

 aqueous layer and zinc dust are shaken out twice with ether. 

 The etheral solution is dried with sodium sulfate, concentrated 

 under diminished pressure and mixed with considerable petro- 

 leum ether. The precipitated substance did not change its melt- 

 ing point of 148° after reprecipitation from ether by petroleum 

 ether or after recrystallization from water. It corresponded in 

 its other properties to the careful description of Mylius. 



0.1993g Substance gave 0.4956g COo and 0.0825g H^O 

 Calculated for CioH,03: C, 68.16; H, 4.58 

 Found C, 67.82; H, 4.63 



Mylius transformed it into its lower melting isomer by dis- 

 tillation in an atmosphere of hydrogen. It is sufficent however, 

 as we found, to simply melt the a-compound in an evacuated 

 flask. After keeping it in a melted condition 10 minutes in a 

 bath at 160-70°, a yield of 70 per cent of /3-hydro juglone was 

 obtained. It was found best to extract the cooled product with 

 carbon tetrachloride in which the a-compound is much more 

 completely insoluble than in chloroform. The carbon tetrach- 

 loride solution was concentrated in vacuum and the ^-hydro- 

 juglone recrystallized from alcohol or petroleum ether. It 

 forms six sided plates, melting at 96-7°. 



The transformation into the a-compound is readily carried 

 out, as Mylius stated, by heating with alcoholic aqueous hydro- 

 chloric acid. It is also successfully obtained by dissolving the 

 i^-compound in dilute sodium hydroxide, containing a little 

 stannous chloride, and acidfying. 



«Ber. der deutsch. chem. Gesell., 17,1946 (1884). 



