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XL 



ON UNSATUBATED /3-DIKETONES.— III. 



By HUGH RYAN and GEBALDINE PLUNKETT, 

 University College, Dublin. 



Read Decemiser 13, 1915. Published Makch 28, 1916. 



By the action of methyl cinnamate on acetone in the presence of sodium 

 wire, Eyan and Dunlea (Proc. Eoyal Irish Acad, xxxii (1913), B, p. 1) 

 obtained an unsaturated /3-diketone, cinnamoyl-acetyl-methane. Similarly 

 from cinnamic ester and acetophenone, methyl-ethyl-ketone and methyl- 

 isopropyl-ketone they obtained cinnamoyl-benzoyl-methane, cinnamoyl- 

 propionyl-methane, and cinnamoyl-isobutyryl-methane respectively. 



Attempts to synthesise dicinnamoyl-methane — the parent substance of 

 curcumin — by this method were unsuccessful, and indeed it was found 

 that although the unsaturated compound, cinnamic ester, condenses with 

 saturated ketones, it does not interact in the same manner with unsaturated 

 ketones. 



It was shown later by Eyan and Algar (Proc. Eoyal Irish Acad, xxxii 

 (1913), B, p. 9) that unsaturated ketones such as benzylidene-acetone and 

 anisylidene-acetone condense readily with dimethyl oxalate, in the presence 

 of sodium, to form unsaturated /3-diketones, such as methyl cinnamoyl- 

 pyruvate and methyl p. methoxycinnamoyl-pyruvate, and that these diketones, 

 as well as the diketone-acids formed by their gentle hydrolysis, have well- 

 marked tinetogenic properties. 



In the present communication we deal with the conversion of veratrylidene- 

 acetone into the unsaturated /3-diketone, methyl 3.4-dimethoxycinnamoyl- 

 pyruvate. The latter compound formed the benzeneazo-derivative, and the 

 isoxazol characteristic of ]3-diketones. It was also converted into 

 3.4-dimethoxycinnamoyl-pyruvie acid. 



Similarly from piperonylidene-acetone we obtained methyl methylene- 

 3.4-dioxycinnamoyl-pyruvate, and the corresponding acid. 



A comparison of the shades obtained with mordanted wool, and some of 



K,I,A. PROC, VOL, XXXIII., SECT, B, [2 G] 



