178 



rivatives. He has fouiicl, (1) that substances of tlie type of acetoaceticether 

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

 ence of diethylamine or jiiperidine to form 1.5 diketones, and that these 

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

 2-keto-R-hexene derivatives; (2) that desoxybenzoin adds itself to sub- 

 stances of the type benzalacetylacetone forming 1.5 diketones, whicli, by 

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



Recently the study has been extended to include the reactions wliich 

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

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

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

 actions, /\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, tliat in place of the unsatured 

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

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

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

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

 E(iual volumes of a ten per cent, solution of sodium hydroxide may be 

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

 take place but tlie yields are very much poorer. 



In tlie i)resent paper the study is limited to the consideration of only 

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

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



I. ADDITION OF BENZOIN TO OUMINALACETOXE. 



.i-4-(lii>ht'iiiil-')-ciniuil-4-().ni-^,^-k('t()-R-h'.n'a('. 

 CU.CoH, .ClI . (CHa). 



C«H5. C.(OH). 



CeH« . C 



' Ann. iSl, 25. Ann. 

 = Ann. 30S, 223. 



55,321. 



CH, 



CO 



CH 



