5-Phenylbenzylamine compounds, process for their production and intermediates for their synthesis

A compound selected from the following (A) to (F):

• (A) [2-methoxy-5-(4-fluorophenyl)benzyl][(2S,3S)-2-phenylpiperidin-3-yl]amine
• (B) [2-methoxy-5-(4-chlorophenyl)benzyl][(2S,3S)-2-phenylpiperidin-3-yl]amine
• (C) [2-methoxy-5-(4-cyanophenyl)benzyl][(2S,3S)-2-phenylpiperidin-3-yl]amine
• (D) [2-methoxy-5-(2-fluoro-4-cyanophenyl)benzyl][(2S,3S)-2-phenylpiperidin-3-yl]amine
• (E) [2-methoxy-5-(4-cyanophenyl)benzyl][(2S,3S,6R)-6-methyl-2-phenylpiperidin-3-yl]amine, and
• (F)[2-methoxy-5-(2-fluoro-4-cyanophenyl)benzyl][(2S,3S,6R)-6-methyl-2-phenylpiperidin-3-yl]amine
• or a pharmaceutically acceptable salt thereof.

A process for preparing a 5-phenylbenzylamine compound represented by the formula [1-a]:

• wherein R1 represents a halogen atom, a lower alkyl group, a halogeno-lower alkyl group, a lower alkoxy group, a hydroxy-lower alkyl group, a lower alkoxy-lower alkyl group, an amino group optionally substituted by a lower alkyl group, phenyl group, naphthyl group, nitro group, cyano group, —CO—NH-lower alkyl, —CO—N(lower alkyl)2, —NH—CO-lower alkyl, or —COO-lower alkyl,
• R2 represents a hydrogen atom, a halogen atom, a lower alkyl group, a halogeno-lower alkyl group, a lower alkoxy group, or cyano group,
• R3 represents a hydrogen atom, a halogen atom, a lower alkyl group, a halogeno-lower alkyl group, a lower alkoxy group, or cyano group,
• Ra represents a hydrogen atom, a halogen atom, a lower alkyl group, a halogeno-lower alkyl group, or a lower alkoxy group,
• Rb1 represents a hydrogen atom, a halogen atom, a lower alkyl group, a halogeno-lower alkyl group, or a lower alkoxy group,
• Rb2 represents a hydrogen atom, a halogen atom, a lower alkyl group, a halogeno-lower alkyl group, or a lower alkoxy group,
• Rc1 represents a hydrogen atom, a lower alkyl group, or an acyl group,
• Rc2 represents a hydrogen atom, or a lower alkyl group,
• Rd represents a hydrogen atom, a lower alkyl group, or an acyl group,
• Re represents a hydrogen atom or a lower alkyl group,
• Rf represents a lower alkyl group or a cyclic lower alkyl group, said process comprising:
• subjecting a compound represented by the formula [2-a]:
• wherein R1, R2, R3, Ra, Re and Rf have the same meanings as defined above,
• and a compound represented by the formula [3]:
• wherein Rb1, Rb2, Rc1, Rc2 and Rd have the same meanings as defined above, to a reductive condensation reaction, and making the product a pharmaceutically acceptable salt, if desired.