Question

Draw a mechanism for the acetylation of p-methylaniline in reaction 3.

Reaction 3: Acetylation NH2 NH2 + NH2 (acetic anhydride) NH2 NH2 m-methylaniline p-methylaniline O-methylaniline m-methylaniline HN o-methylaniline O p-methylacetanilide Procedure for Reaction 3: 1) The solution of the three isomers of methylaniline in ethyl acetate was cooled to 0 °C. 2) An equimolar amount of acetic anhydride to the quantity of p-methylaniline theoretically present in the solution was added dropwise with stirring. 3) The stirring was continued for 15 minutes while the reaction mixture warmed to room temperature. 4) TLC analysis confirmed the selective acetylation of p-methylaniline. 5) The reaction mixture was then extracted twice with 5 mL of a 10 % HCl solution. 6) The aqueous layer was set aside, and the organic layer was washed with 5 % sodium bicarbonate solution, dried with anhydrous sodium sulfate and evaporated to afford crude p-methylacetanilide. Recrystallization 7) 3 mL of hot ethanol was added to the crude p- methylacetanilide. 8) The flask was then removed from the heat and allowed to cool to room temperature, and then the flask was placed into an ice bath. 9) The crystals were collected by vacuum filtration, rinsing the flask with cold ethanol. 10) The crystals were dried and 750 mg of product was obtained.

Answer 1

La + ΝΗ, H (p-meth methylaniline) Nole HAN ĐII acts as ne nucleophile due to high electron density on 'N' ed NHL S+11 acti as electrophile due to partially positive carbon. NH carbonyl carbon. p-methylacetanilide