This invention discloses a compound in formula (I), its optical isomer or its medicinal salt, its preparation and usage. In them the definition of R1,R2,R3 and R4 can be seen in instruction manual. This kind of compound can be optical isomer and also can be racemic mixture. After ingested, in the body this kind of compound can be transformed into 1-[2-dimethyl amid -1-(4-hydroxy group phenyl)-ethyl group cyclohexanol that has neural pharmacological activity and can cure central nervous system disease by obstructing reuptake of 5-HT and arterenol (NA).