Ai.GAR — Unsaturated Ketones derived from Diaceto-Orcinol. 115 



a-Dipiperonylidene-diaceto-orcinol. 



CO . CH : CH . CsHs : O2CH2 



HO/\OH 



I I 



\/C0 . CH : CH . CsHs : OiCH: 



CH3 



A mixture of diaeeto-orcinol (3 grains), piperonal (8 grams), and absolute 

 alcohol (70 CCS.), was heated to boiling, and 10 c.cs. of 50 per cent, sodium 

 hydroxide were added gradually to the solution. The mixture was heated 

 for fifteen minutes, then cooled and acidified with alcoholic hydrochloric acid. 

 The yellow precipitate was filtered, washed witli water and alcohol, and 

 crystallised from benzene. It was further puriiied by solution in alkali and 

 precipitation with hydrochloric acid. Tiie precipitate was filtered, washed 

 with water, dried and crystallised from boiling xylene. 



0-163 substance gave 0-4098 CO, and 0-0698 H,0 

 corresponding to C 68-56, H 4-75 

 a;H„0, requires C 68-57, H 4-27. 



a-Dipiperonylidene- diaeeto-orcinol crystallises from boiling xylene in 

 orange-yellow prisms, which soften at 234" C. and melt at 236-237° C. It is 

 insoluble in alcohol, but soluble in chloroform, and in hot benzene or xylene. 

 A solution of the substance in boiling alcohol gives a faint brownish-yellow 

 coloration with ferric chloride, the weakness of the colour being probably due 

 to the fact tliat the compound is very sparingly soluble. Concentrated 

 sulphuric acid colours the crystals purple, dissolving them to a purple-red 

 solution. 



^-Bipiperonylidene-diaceto-orcinol. 



During the preparation of the o compound, portion of the product was 

 heated with chloroform and a little alcoholic hydrochloric acid, with a view to 

 decomposing any sodium salt which might be present. As a result a yellow, 

 very insoluble substance was formed. The mixture was evaporated to dryness, 

 and the residue crystallised from boiling xylene, in which it is much less 

 soluble than the a compound. 



0-1705 substance gave 0-4291 COs and 0-0714 H^O 

 corresponding to C 68-63, H4-65 

 CjvHjoOs requires C 68-57, H 4-27. 



