| 摘要 |
Di-ethylcarbonato esters of the formula <FORM:0561573/IV/1> where R2 represents two identical alkyl groups, are prepared by esterifying an aqueous solution of a water soluble salt of a dihydroxyphenalkyl-dialkylamine with ethyl chlorocarbonate in an inert atmosphere. The esterification product is extracted preferably with ether, and finally precipitated in the form of a hydrochloride by reaction with hydrogen chloride. In examples (1) 3 : 4 - dihydroxyphenethyldimethylamine hydrochloride is treated in small amounts alternately with dilute sodium hydroxide and ethyl chloro-carbonate. The product is extracted with ether and finally precipitated with hydrochloric acid gas; (2) b -(3 : 4-dihydroxyphenyl) propyldimethylamine is treated as in example (1); (3) b -(3 : 4-dihydroxyphenyl)-isopropyldimethylamine is treated as in example (1). b - (3 : 4 - dihydroxyphenyl) propyldimethylamine is prepared from 3 : 4-dimethoxyacetophenone by condensation with ethylbromoacetate to form ethyl-b -(3 : 4-dimethoxyphenyl) b -hydroxybutyrate which is dehydrated, catalytically reduced and then saponified to form b -(3 : 4-dimethoxyphenyl) butyric acid. This is converted into the amide and treated with sodium hypochlorite, and methylated with formaldehyde. The required product is formed by a subsequent demethylation. b - (3 : 4 - dihydroxyphenyl) isopropyldimethylamine is prepared from veratric aldehyde, and ethyl propionate which form by the Chaisen reaction a - methyl - 3 : 4 - dimethoxycinnamic acid. This is reduced, converted into the amide, subjected to the Hoffmann reaction, and then an Eschweiler reaction and finally demethylated.
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