The present invention relates to a (2R, 3R)-3-(3-substituted phenyl)-2-methyl n-pentanamide compounds as shown in the formula I and the preparation method thereof, wherein, the substituents are as defined in the specification, the present invention further relates to a use of the above compounds for the preparation of tapentadol II or its pharmaceutically acceptable salt, and the intermediates involved in the preparation process.

Provided is a process for preparing racemic nicotine from 1-methyl-3-nicotinoyl-2-pyrrolidone or a salt thereof using one-pot process. The process comprises the following steps: 1) in a reaction vessel, reacting 1-methyl-3-nicotinoyl-2-pyrrolidone or a salt thereof in the presence of a suitable solvent and a strong acid by heat

The present invention relates to a (2R, 3R)-3-(3-substituted phenyl)-2-methyl n-pentanamide compounds as shown in the formula I and the preparation method thereof, wherein, the substituents are as defined in the specification, the present invention further relates to a use of the above compounds for the preparation of tapentadol II or its pharmaceutically acceptable salt, and the intermediates involved in the preparation process.