Ryan & Cahill — Condensation of Aldehydes with Mcthylethy Ike lone. 335 



ketone melting at 53° 0. and a substance melting at 93-95° C, which is 

 probably di-^;-niethoxyphenyl-methyltetrahydropyrone with the formula : — 



o 



HjCHCL 



CO 



When this substance was treated with excess of anisaldehyde in the presence 

 of alcoholic hydrochloric acid, further condensation ensued, witli, however, the 

 elimination of two water molecules. The course of the reaction was therefore 

 quite analogous to that by which Eyan and Devine had obtained the com- 

 pound CasHaoO from benzaldehyde and diphenylmetliyltetrahydropyrone. 



This compound was also obtained by the acid condensation of excess of 

 anisaldehyde with anisylidene-methylethyl-ketone or methylethyl-ketone. In 

 the latter case the reactions may be represented thus :- — 



CH3 . CO . GHj . CH3 + CH3O . C0H4 . CHO + HCl 



= CH3 . CO . CH(CH;,) . CHCl . CeH4 . OCH3 + H,0 



CHs . CO . CH(CH3) . CHCl . CcH4 . OCH3 + CH3O . C6H4 . CHO 



= CH3O . CeH4 . CH . CH, . CO . CH . CH3 



I I + HCl 



CH . CeH4 . OCH3 



C»„H2o.04 + CH3O . C6H4 . CHO = Q^^^,<^, + 2H30 



A similar body having the empirical formula 'CosHsjOc was formed by 

 the action of excess of piperonal on anisylidene-methyletliyl-ketone in tke 

 presence of alcoholic hydrochloric acid. 



Experimental. 

 A. — Action of Aldehydes on Methylelhyl-Kctone- in the Presence of Alkali. 



1. Piperonal. 



Piperonylidene-methylethyl-ketone, 



CH2O2 . CfiHsCH : CH . CO . CH^ . CH3. 



A mixture of 15 g. of methyletliyl-ketone and 50 g. of piperonal with 

 750 c.c. of a dilute aqueous solution of sodium hydroxide was shaken 

 mechanically for seven days. The yellow oily solid, wliioh separated, was 

 filtered, washed with water, and recrystallised several times from petroleum 



