Ryan & Cahill — Condensation of Aldehydes tvith Methylethylketone. 337 

 (b) Di-p-metTioxyphenyl-metKi/ltetrahydropyrone. 



HCO.HC, CH CHC,HaOCH, 

 o 4 6 I I t> -H- 5 



HjCClH ^CH^ 

 CO 



A mixture of equivalent quantities of anisaldehyde and anisylidene- 

 uiethylethyl-ketone was shaken with a large volume of dilute aqueous alkali 

 for twenty-one days. The oil, which separated, was extracted with ether, 

 and, after evaporation of the ether, the unchanged anisylidene-methylethyl- 

 ketone was distilled in a current of superheated steam. The residue was 

 extracted with ether. The oily residue left when the ether had evaporated 

 crystallised after some days. It was purified by recrystallisation from 

 petroleum ether or by distillation in vacuo. It melted at 93-95° 0., and gave 

 on analysis the following results : — 



0-1.S39 substance gave 0-3621 00, and 0-0820 Hfi, 

 corresponding to C 73-6, H 6-9. 

 C.20H22O, requires C 73-7 H 6-7. 



It crystallises in prisms, scarcely soluble in petroleum ether, soluble in ether 

 or chloroform, and readily soluble in hot alcohol. The crystals are coloured 

 reddish-yellow by contact with strong sulphuric acid, in which they dissolve 

 to a reddish solution. 



B. — Action of Anisaldehyde on MctJiylethyl- Ketone in the Presence 



of Acids. 



1. A solution of 6 g. of methylethyl-ketone and 34 g. of anisaldehyde in 

 150 c.c. of alcohol was cooled in a freezing mixture, and saturated with 

 gaseous hydrochloric acid. On standing in a tightly stoppered flask the 

 solution turned a reddish colour, and gradually deposited an oily substance, 

 which in the course of a few days solidified. 'J'he supernatant liquid was 

 decanted and evaporated, leaving a resinous solid. The two solids were 

 mixed and recrystallised from hot alcohol. This compound, which melted at 

 150°C., was also obtained by the action of anisaldehyde on both anisylidene- 

 methylethyl-ketone and di-j3-methoxyphenyl-methyltetrahydropyrone in the 

 presence of alcoholic hydrochloric acid. 



2. A solution of 2-5 g. of anisylidene-methylethyl-ketone and 10-5 g. of 

 anisaldehyde in 20 c.c. of alcohol, which had previously, been saturated with 

 dry gaseous hydrochloric acid, was allowed to remain in a stoppered flask for 



