991the pH values were determined, and the spectra were measured on a Beckman DK 2 recording spectrophotometer a t room temperature in 1-cm. silica cells.
2-Hydroxy-d,4'-dimethoxychalcone (XIII).-( a )The chalcone SI11 was synthesized by the following modification of Robinson's procedure.21 A solution of potassium hydroxide (11.5 g.) in the minimum quantity of water was added to a solution of ovanillin ( i . 6 9.) and p-methoxyacetophenone (8.3 g.) in ethanol (40 nil.). After 20 hr., water (250 ml.) and glacial acetic acid (3.5 ml.) were added. The yellow product was collected and recrystallized from acetone-methanol.The chalcone XI11 separated as yellow, glisteningplates, m.p. 141-142".
VINYLATION OF PENTAERYTHRITOL 47 1 monia waa evaporated. The residue was treated with 100 removed. The residue was distilled to give 28.9 g. (89%) of ml. of water and 110 ml. of concentrated hydrochloric 1-dimethylamino-1-phenylpropane (IVb), b.p. 58-58.5' acid, and most of the t-butyl alcohol was distilled. After at 2.5 mm., ny 1.5016. The picrate, m.p. and mixed m.p cooling, the acid solution was made alkaline with sodium 167-168', was recrystallized from ethanol. hydroxide solution, and the resulting mixture was extracted with ether. The ether extract was dried, and the solvent DURHAM, N. C.The catalytic vinylation of pentaerythritol in aqueous base afforded a mixture of products from which the pure divinyl ether I1 was isolated in 22% yield. The total mixture of compounds obtained from the aqueous vinylation was treated further with acetylene under non-aqueow basic conditions to give a mixture of the tetravinyl ether of pentaerythritol (V) (60-?0%) and 5,5-di(vinyloxymethyl)-2-methyl-l,3-dioxane (VII) (3040%). There appears t o be a relationship between the acidity of an alcohol and its tendency to undergo vinylation in an aqueous solution. Sixiiple monohydric aliphatic alcohols do not undergo base-catalyzed vinylation in water, whereas, polyhydroxy compounds capable of forming intramolecular hydrogen bonds react with acetylene in aqueous base to give products of vinylation.
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