Sanofi-Aventis

Daniel Capraro

Gilles Anne-Archard

Alain Alcade

The invention relates to a process for preparing a 4-amino-4-phenylpiperidine (I): in which R is hydrogen or a (C&#x2013;C)alkyl group, characterized in that a 1-protected 4-piperidone (II): in which Pr' represents a removable N-protecting group, is treated sequentially first with an alkali metal cyanide and then with an amine ENHPr&#x2033; (III) in which E represents a group R&#x2032;=(C&#x2013;C)alkyl, or an N-protecting group and Pr&#x2033; is an N-protecting group, the protecting group(s) being removable under the same conditions as Pr&#x2032;; then the compound thus obtained (IV) is subjected to a Grignard reaction with a phenylmagnesium halide, the two or three protecting groups are removed from the compound thus obtained (V) and compound (I) is isolated or in the form of the free base, which is converted into one of its salts.

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Portet sur Garonne, France

Daniel Capraro