Question

write a detailed mechanism for a) the hydrolysis of methyl salicylate in basic solution b) the acetylation of salicylic acid in acidic solution and c) the acetylation of vanillin in basic solution.

Answer 1

a) hydrolysis of methyl salicylate in basic medium

the sodium hydroxide is the base being used from which the hydroxide ion adds accross the double bond and an adduct is being formed. the oxygen anion from this adduct adds back to the carbon atom by which the methox group is eliminated to give the salicylic acid.

b. acetylation of salicylic acid in acidic medium

the oxygen of the hydroxyl group of salicylic acid being basic (has acidic proton ) adds on to the acetic anhydride acetyl group by which the acetate moeity was eliminated to yield acetyl salicylate and acetic acid which can easily be removed.

c. acetylation of vanillin in basic solution. (http://www.scribd.com/doc/247755404/Organic-Synthesis-of-Vanillin#scribd)

the vanillin is a phenolic compound dissolves in sodium hydroxide solution was added acetic anhydride wherein the anion of phenolic oxygen adds on to the acetyl group of acetic anhydride by which the acetic acid is liberated is consumed or neutrilized by the base, The acetylation of vanillin is accomplished.

the attached reference details the same procedure.