4-phenylpiperidine compounds

The invention relates to a compound, and pharmaceutically acceptable salts, having the formula I: ##STR1##

wherein:

• R represents an alkyl or alkynyl group having 1-4 carbon atoms, or a phenyl group optionally substituted by C_1-4 alkyl, alkylthio, alkoxy, halogen, nitro, acylamino, methylsulfonyl or methylenedioxy, or represents tetrahydronaphthyl,
• R¹ represents hydrogen, trifluoro (C_1-4) alkyl, alkyl or alkynyl,
• X represents hydrogen, alkyl having 1-4 carbon atoms, alkoxy, trifluoroalkyl, hydroxy, halogen, methylthio or aralkoxy,
• R² represents:
  • a C1-C10 alkyl group,
  • a phenyl group optionally substituted by one or more of the following groups:
  • a C1-C10 alkyl group,
  • a halogen group,
  • a nitro group,
  • hydroxy group,
  • and/or an alkoxy group.