Question

Synthesis of Dimedone lab

Descibe and explain the possible effect on your results of the following experimental errors or variations

a) You neglected to evaporate methanol from the reaction mixture (hint: consider the role of the hydroxide ion at this point in the synthesis and that methanol and hydroxide will exist in the following equilibrium: HO- + MeOH <--> H2O + MeO-

b) The mesityl oxide bottle was contaminated with water

c) The bottle labeled "dimethyl malonate" actually contained dimethyl maleate.

Answer 1

a) If you neglected to evaporate methanol from the reaction mixture methanol and hydroxide will exist in the following equilibrium: HO- + MeOH <--> H2O + MeO- and ester hydrolysis reaction will be sluggish.

b) The mesityl oxide bottle was contaminated with water then under aqueous basic condition ester group will hydrolyzed to acid followed by decarboxidation of one acid group will occur and results in side product.

c)The bottle labeled "dimethyl malonate" actually contained dimethyl maleate then no reaction of mesityl oxide with dimethyl maleate because both are michael acceptor