Ravizza S.p.a.

Alberto Verga

Ermanno Valoti

Oreste Piccolo

Roberto Signorini

A process for the resolution of (.+-.) 2-[2'-(p-fluorophenyl)-5'-benzoxazolyl]-propionic acid, indicated for brevity as (.+-.)-FBP, by treatment with (-)N-R-glucamine, indicated for brevity as NRG and in which R is an alkyl or cycloalkyl radical, followed by fractional crystallization of the mixture of the diastereoisomer salts obtained, and by separation of the precipitate, from which, by hydrolysis, (.+-.)-FBP is obtained with the required purity characteristics. The levorotatory antipode, (-)-FBP, is racemized, preferably by the formation of one of its esters, which is then hydrolyzed to give the (.+-.)-FBP, which is recycled to the treatment with NRG. (+)-FBP and (-)-FBP salts with NRG obtained by said process.

Process for the resolution of (.+-.)

A process for preparing 2(4-fluorophenyl).alpha.-methyl-5-benzoxazole acetic acid starting from 4-hydroxy-3-amino-phenylacetic acid, which is firstly reacted with 4-fluorobenzoyl chloride, and the product obtained is reacted with phosphoric acid; the 2(4-fluorophenyl)5-benzoxazole acetic acid obtained in this manner is esterified with ethyl alcohol, and the ester is treated with diethyloxalate; the ethyl 2(4-fluorophenyl)5-benzoxazole oxalacetate obtained is reacted with formaldehyde and potassium carbonate to obtain ethyl 2(4-fluorophenyl)5-benzoxazole acrylate, which is hydrolysed to obtain the corresponding acid, from which the 2(4-fluorophenyl).alpha.-methyl-5-benzoxazole acetic acid is obtained by hydrogenation.

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Milan, Italy

Alberto Verga