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

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

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

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

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

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

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

A method for preparing a compound ERA corresponding to formula I, the method comprising;

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