10 Proceedings of the Royal Irish Academy. 



unsaturated ester condenses normally with a saturated ketone. As benzoic 

 ester does not condense, under the usual conditions required for similar 

 reactions, with benzylidene-acetone to give the cinnamyl-benzoyl-methane of 

 Kyan and Dunlea : — 



C S H 5 CH : CH . COCH 3 + C 2 H 5 OO0 . C 6 H 6 = C e H 5 CH : OH . CO . OIL . CO . C,H 5 



+ C 2 H 5 OH, 



it is apparent that the main factor of the abnormality is the unsaturated 

 nature of the mono-ketone. 



"We are at present unable to offer any explanation of the failure of the 

 reaction to take the expected direction, and all the more since, as we shall 

 see in the experimental part of this communication, unsaturated ketones, such 

 as benzylidene-acetone and anisylidene-acetone, condense readily with oxalic 

 ester to give good yields of the corresponding /j-diketones : — 

 C 6 H 5 CH : CH . CO . OH, + CH.OOC . COOCH 3 = 



C C H 6 CH : CH . CO . CH 2 . CO . COOCH 3 + CH 3 OH. 



When we had succeeded in condensing oxalic ester with an unsaturated 

 ketone, we again' tried, under various conditions, to condense benzoic ester 

 with benzylidene-acetone, and failed to obtain cinnamyl-benzoyl-methane. 



The unsaturated diketones derived from dimethyl oxalate, benzylidene 

 acetone, and anisylidene-acetone respectively, give the reactions characteristic 

 of the saturated j3-diketones. For instance, hydroxylamine hydrochloride 

 converts them into isoxazoles. Like the orthohydroxy ketones, their sodium 

 derivatives are only sparingly soluble in alcohol, and their tinctorial properties 

 are more pronounced than those of the corresponding diketones described in 

 the previous communication. 



Experimental Part. 



Methyl-cinnamyl-pyruvate, C 6 H 5 . CH : CH . CO . CH 2 . CO . COOCH 3 . 



15 grins, of benzylidene-acetone were mixed with 30 grms. of dimethyl 

 oxalate, and heated in a dry, round flask until the mixture had melted; 

 25 grms. (slight excess) of fine sodium wire were then added, when an 

 energetic reaction set in with separation of a deep red solid. During the 

 first preparation a much larger excess of sodium was used ; but it was found 

 that this tended to hydrolyse the required ester: consequently in later 

 preparations only a slight excess of sodium was employed. When the reaction 

 had subsided, about 50 c.cs. anhydrous ether was added, and the stoppered 

 flask was set aside for a few hours at the ordinary temperature. The excess 



