Ryan and Plunkett — On Unsaturated fi-Diketones. — III. 205 



5. '^A-Dimethoxycinnamoyl-Pyruvic Acid. 

 (CH 3 0) 2 C 6 H 3 . CH : CH . CO . CH 2 . CO . COOH. 



Diinethoxycinnanioyl-pyruvic methyl ester (2-92 grams) was shaken with 

 40 c.cs. of semi-normal, alcoholic potash in a stoppered flask until solution 

 had taken place, and was then let stand for twenty-four hours. About 100 c.cs. 

 of water were added, and the alkaline solution was extracted with ether. 

 From its solution in the latter solvent the acid was extracted by means of 

 dilute sodium carbonate ; the aqueous layer was again acidified, and once 

 more extracted with ether. The ether was distilled, and the residue was 

 recrystallized from dilute alcohol. When dried at 105° C. it melted at 185° C, 

 and gave on analysis the following results : — 



0-1422 substance gave 0-3152 C0 2 and 0-0656 H 2 

 corresponding to C 60-45, H 5\L3 

 C 14 H,A requires C 60-43, H 5'0. 

 Dimetho.rycinnamoyl-pyruvic acid consists of orange-red prisms which are 

 sparingly soluble in hot alcohol or cold benzene, and readily soluble in chloro- 

 form. Its solutions have a green fluorescence. 



Concentrated sulphuric acid colours the crystals reddish-violet, and 

 dissolves them, forming a reddish-violet solution. 



A solution of the substance in alcohol gives a dark-brown coloration with 

 ferric chloride. 



When mordanted wool is boiled with a solution of the substance in 

 diluted alcohol, the following shades are obtained : — 



Mordant. Colour. 



Aluminium Sulphate, . . Orange-red. 

 Potassium Dichromate, . . Chocolate-red. 

 Stannous Chloride, . . Orange-brown. 

 Ferric Sulphate, . . . Dark chocolate-brown. 



6. Piperonylidene- Acetone. 

 To a solution of 20 grams of piperonal in a mixture of 85 c.cs. of acetone 

 and 30 c.cs. of water, about 3 c.cs. of 25 per cent, sodium hydrate were added, 

 and the mixture, after vigorous shaking, was let stand for an hour in a warm 

 place. After addition of 100 c.cs. of water, the piperonylidene-acetone was 

 filtered, and recrystallized from alcohol. It melted at 107°-108° C. 



7. Methylcne-'SA-Dioxycinnamoyl-Pyruvic Methyl Ester. 

 CH 2 0*C 6 H 3 . CH : CH . CO . CH 2 . CO . COOCH 3 . 

 A mixture of 9 grams of piperonylidene-acetone and 15 grams of dimethyl 

 oxalate was heated in a dry flask until it melted. On addition of 2-5 grams 



