Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Patent
1981-03-05
1982-07-06
Garner, Vivian
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
560126, C07C 6700, C07C 69716
Patent
active
043384595
ABSTRACT:
A diester of .alpha.-acetyl-.alpha.'-methylsuccinic acid is prepared in improved yield under substantially anhydrous process conditions which minimizes decomposition of that diester by reacting an acetoacetate ester with an .alpha.-halopropionate ester in a solvent mixture containing a non-polar, aprotic liquid, e.g., toluene, and a dipolar aprotic liquid, e.g., DMF, at from about 50.degree. C. to reflux temperature in the presence of a phase transfer agent, a catalytic amount of iodide ion and solid form, substantially anhydrous alkali metal base or basic salt. Further improvement is obtained when the completed reaction mixture is diluted with water and adjusted to pH 8 to 9, and when the DMF/acetoacetate ester ratios are between about 1.7 and 3. The resulting diesters can be used under the conditions of this invention as intermediates in processes for making ibuprofen by combining and reacting the .alpha.-acetyl-.alpha.'-methylsuccinate diester with vinyl isobutyl ketone (or the corresponding Mannich base plus an alkylating agent) and an alkali metal base, e.g., potassium tert-butoxide, for a time sufficient to form a reaction mixture containing the .alpha.-methyl-.alpha.'-acetyl-.alpha.'-(5-methyl-3-oxohexyl)succinate ester, which can then be converted to ibuprofen by procedures now known.
REFERENCES:
patent: 3213155 (1965-10-01), Schriesheim et al.
patent: 4194053 (1980-03-01), White
Garner Vivian
Reynolds John T.
The Upjohn Company
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