The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 06, 1982
Filed:
Mar. 05, 1981
Francis L Shenton, Portage, MI (US);
The Upjohn Company, Kalamazoo, MI (US);
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.