Acetic Acid → 4-(2-Fluorobenzylthio)-4-(2-fluorophenyl)-1-methylpiperidine maleate

Participants

Reaction Steps

A mixture of 4-(2-fluorophenyl)-4-hydroxy-1-methylpiperidine of Example 1a (15.8 g), 12 ml of 2-fluorobenzyl mercaptan and 20 ml of boron trifluoride etherate in 15 ml of glacial acetic acid is stirred at 65°-70° C. for 16 hours. The excess reagents are removed under reduced pressure, the residue is triturated with 300 ml of 0.5N HCl and 100 ml of ether. After standing at 5°-10° C. for 30 minutes, a crystalline precipitate is filtered, air dried and made basic with 10% aqueous NH4OH. The liberated amine is taken up in ether, dried and concentrated to a yellowish oil which is then converted to its maleate in ether, recrystallization of the crude salt from methanol-ether gives colorless prisms, m.p. 153°-154° C. of 4-(2-fluorobenzylthio)-4-(2-fluorophenyl)-1-methylpiperidine maleate.

Provenance & Evidence