178 



rivatives. He has found, (1) tliat substances of tlie type of aeetoaeeticether 

 and aliphatic aldehydes', and aromatic aldehydes^, condense in the pres- 

 ence of diethylamine or piperidine to form 1.5 diketones, and that tliese 

 diketones, with loss of water and ring formation, are converted into 

 /12-keto-R-liexene derivatives; (2) that desoxybenzoin adds itself to sub- 

 stances of the type benzalacetylacetoue forming 1.5 diketones, which, by 

 loss of water and ring formation, yield 2-keto-R-hexene derivativts. 



Recently the study has been extended to include the reactions which 

 might take place between the ketols — benzoin, cuminoin, furoin, anisoin 

 and piperonoin — and the unsaturated ketones-benzalacetone, cuminalacet- 

 one, p-methcxy-benzalacetone, and piperonyleuacetone. In all the re- 

 actions, A 2-keto-R-hexene derivatives are formed, except in those in which 

 furoin is used. Under no conditions has it been possible to bring about 

 any interaction in any of the experiments in which furoin is used. All of 

 the other reactions progress smoothly and excellent yields are obtained in 

 each case. It has been ascertained also, that in place of the unsatured 

 ketone, a mixture of the corresponding aldehyde and acetone may be used 

 and the course of the reaction is in no way changed, but the yield is ma- 

 terially increased. To insure the completion of the reactions, however, it 

 is necessary to boil the mixtures for fifteen minutes on the water-bath. 

 Equal volumes of a ten per cent, solution of sodium hydroxide may be 

 used instead of the alcoiiolic sodium ethylate and the same reactions will 

 take place but the yields are very much poorer. 



In the present paper the study is limited to the consideration of only 

 those cases, which will in a general way, indicate, ( 1 ) the nature of the 

 products formed and, (2) the extent to which tlie reaction is applicable. 



I. ADDITION OF BENZOIX TO CUMIXALACETOXE. 



.i-4-<Iij)lieniil-')-<-iiiiii/l-4~<>-i'!l-_ .,~^.'i to-R-hc.irne. 

 CII.CcH4 .CH.lCHa). 



CbHs . C . (OH) 



CoHe.C 



CH, 



CO 



^ Ann. ;.'Si, 25. .\nn. -V, 321. 

 = Ann. .3').-% 223. 



CH 



