Draw a mechanism for the reaction of acetaldehyde with methanol in the presence of an acid.

Mechanism of acetaldehyde reacting with methanol in acid, showing nucleophilic addition.

Alternative mechanism for acetaldehyde and methanol reaction in acid, illustrating imine vs enamine formation.

Detailed mechanism of acetaldehyde and methanol reaction in acid, highlighting nucleophilic steps.

Another view of the acetaldehyde and methanol reaction mechanism in acid, focusing on nucleophilic addition.