XX. Draw a detailed mechanism for the esterification of pentanoic acid with methanol (acidic conditions). Show appropriate intermediate structures and steps in the reaction

19. Propose an efficient synthesis of benzaldehye from toluene. Write complete equations showing the structure of all reactants and products for each step.

The acetoacetic ester synthesis is a carbonyl alkylation reaction. It is used to prepare methyl ketones from primary alkyl halides, lengthening the carbon chain by three atoms. Thus, the product can be visualized as being a "substituted acetone." The reaction consists of three steps: generation of the enolate anion followed by SN2 reaction with a primary alkyl halide, ester hydrolysis under acid conditions, and decarboxylation. м Br H3C H3C OEt 1. NaOEt 2. H₂O* 3. heat H₂C. Draw curved arrows to show the movement of electrons in this step of the mechanism. CO₂ EtOH CH3 Arrow-pushing Instructions H3C 1:0: :0: :Br: Br: H₂C CH3 CH3 H3C CH3 7b

An ester can be produced by the reaction between an acyl chloride andalcohol.  By making use of an appropriate mechanism, show how ethylbenzoate is produced by the reaction between ethanol andbenzoyl chloride. Clearly indicate the steps in the mechanism.