Preparation method for rivastigmine, intermediates thereof, and preparation method for said intermediates

A method for preparing a compound of formula IX, the method comprising:

• methylating a compound of formula III to obtain a compound of formula VI,
• wherein the compound of formula III comprises:
• wherein the compound of formula VI comprises:
• demethylating a compound of formula VI to obtain a compound of formula VIII;
• wherein the compound of formula VIII comprises:
• and
• engaging a condensation reaction between the compound of formula VIII and ethyl(methyl)carbamic chloride to obtain a compound of formula IX,
• wherein the compound of formula IX comprises:
• wherein Y is selected from the group consisting of SO4CH3, CO3CH3, SO3CF3, SO3F, Cl, Br, and I.

A method for preparing a compound of formula IX, the method comprising:

• methylating a compound of formula IV to obtain a compound of formula VI
• wherein the compound of formula IV comprises:
• wherein the compound of formula VI comprises:
• demethylating the compound of formula VI to obtain a compound of formula VIII,
• wherein the compound of formula VIII comprises:
• and
• engaging a condensation reaction between the compound of formula VIII and ethyl(methyl)carbamic chloride to obtain a compound of formula IX,
• wherein the compound of formula IX comprises:
• wherein Y is selected from the group consisting of SO4CH3, CO3CH3, SO3CF3, SO3F, Cl, Br, and I.

A method for preparing a compound of formula IX, the method comprises:

• engaging a condensation reaction between a compound of formula V with ethyl(methyl)carbamic chloride to obtain a compound of formula VII,
• wherein the compound of formula V comprises:
• wherein the compound of formula VII comprises:
• and
• methylating the compound of formula VII to obtain a compound of formula IX
• wherein the compound of formula IX comprises:
• wherein Y is selected from the group consisting of SO4CH3, CO3CH3, SO3CF3, SO3F, Cl, Br, and I.

A method for preparing a compound of formula I, the method comprising:

• debenzylating reacting a compound of formula IX to obtain a compound of formula X,
• wherein the compound of formula I comprises:
• wherein the compound of formula IX comprises:
• wherein the compound of formula X comprises:
• and
• reacting a compound of formula X with L-(+)-tartaric acid to obtain a compound of formula I.