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The manufacture of geranyl-acetone and dihydrogeranyl-acetone and of hexahydro-pseudoionone therefrom
The manufacture of geranyl-acetone and dihydrogeranyl-acetone and of hexahydro-pseudoionone therefrom
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机译：由其制造香叶基丙酮和二氢香叶基丙酮及其六氢假紫酮
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摘要
Geranyl acetone and dihydro-geranyl acetone respectively are prepared by reacting an acetoacetic alkyl ester with geranyl chloride or bromide or with dihydro geranyl chloride or bromide respectively, in the presence of an alkali metal alkoxide and subjecting the resulting 3-carbalkoxy compound to a ketonic hydrolysis. The methods may be used in a synthesis of hexahydropseudo ionone comprising reacting 6-methyl hepten-5-one-2 or 6-methyl heptanone-2 with an alkali metal derivative of acetylene in liquid ammonia solution and treating the product with an acid, partially hydrogenating the resulting acetylenic carbinol in the presence of a hydrogenation catalyst, e.g. nickel or palladium, which selectively reduces a triple bond to a double bond, reacting the resulting linalool or dihydro linalool with aqueous hydrogen chloride or bromide, converting the so-formed geranyl or dihydrogeranyl halide to geranyl or dihydro geranyl acetone as above described and then catalytically hydrogenating the resulting product as described in Specification 788,301 to hexahydro pseudo-ionone. In examples: (1) linalool prepared as described in Specification 788,301 is reacted at 0 DEG C. with aqueous HCl to form geranyl chloride which is reacted with ethyl aceto acetate in benzene containing sodium methylate as catalyst; the resulting 6 : 10 - dimethyl - 3 - carbethoxyundecadien - 5 : 9 - one - 2 is saponified in aqueous alcoholic KOH and the solution is then acidified and heated to yield geranyl acetone which is catalytically hydrogenated to hexahydro pseudo-ionone as described above; (2) 6-methyl heptanone-2 is converted in like manner via the dihydro geranyl chloride or bromide to dihydro geranyl acetone and thence to hexahydro pseudo ionone. Specification 735,828 also is referred to.
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