The Upjohn Co.

Sanjay I Amin

Jerry A Walker

Roger E Gordon

In preparing arylalkanoic acids, e.g. ibuprofen or naproxen, via the conversion of the selected .alpha.-haloketal derivative of a 1-haloethyl aryl ketone to the haloalkyl ester of the arylalkanoic acid using a zinc salt catalyst the improvement comprising reacting a ring-substituted 6-membered ring ketal of the selected 1-haloethyl C.sub.6 -C.sub.12 -aryl ketone with a soluble zinc carboxylate salt to form the corresponding 3-haloalkyl arylalkanoic acid ester. The ester is converted to the alkali metal salt of the acid with base in an aqueous/water insoluble organic liquid mixture and the crude salt is converted to the corresponding acid in an aqueous/water insoluble solvent mixture for the acid, the organic solution of the acid is washed with a pH 7.0 to 8.0 buffer solution, and the arylalkanoic acid product is separated from the mother liquor which mother liquor is recycled to the alkali metal arylalkanoate salt forming step of the process to accumulate and recover the arylalkanoic acid values which remained in the mother liquor.

Arylalkanoic acid process improvement

Ibuprofen is crystallized from a .delta.H.gtoreq.8 liquid such as a C.sub.1 to C.sub.3 -alkanol, e.g., methanol, containing solutions thereof to obtain ibuprofen crystals which are equant (cube, sphere or grain) in shape, which ibuprofen crystals have larger average partile size, higher bulk density, lower bulk volume and improved flow properties compared to previously known bulk ibuprofen crystalline materials.

Crystallization of ibuprofen

2-Aryl-C.sub.3 to C.sub.6 -alkanoate esters are prepared economically by reacting an enol ether of an aryl alkyl ketone with a trivalent thallium salt in an organic solvent. The trivalent thallium ions can be regenerated by adding a peracid and a reactive form of manganese, ruthenium, cobalt, iridium, hafnium, osmium or neobium to oxidize monovalent thallium ions to the trivalent state, in a sequential, continuous or stoichiometric procedure. A continuous process using a Scheibel column is disclosed. The ester intermediate product is then converted to the corresponding 2-aryl-C.sub.3 - to C.sub.6 -alkanoic acid or salt thereof. The aryl group is selected so the resulting acid product will be a useful compound such as an anti-inflammatory, analgesic and anti-pyretic drug or agriculturally useful product. Examples of drug acids which can be made by this process include ibuprofen, flurbiprofen, fenoprofen and naproxen and the like.

Growing community of inventors

Oshtemo Township, MI, United States of America

Sanjay I Amin