What do deamination and decarboxylation reactions have in common?

Well, let's take a look at them in acidic conditions.

DECARBOXYLATION

Note the intramolecular rearrangement.

DEAMINATION

Unlike in decarboxylation, where you get a proton in place of a carboxyl group, in deamination, you get a carbonyl in place of an amino group (remember how you remove an imine group by adding acid and water, thereby giving back the carbonyl?).

But see the similarities in the intramolecular rearrangements? Yeah, they both seem to involve multiple arrows in one step. That is hard to make happen.

WHY?

It works in part from the high temperatures, but most importantly, the #\mathbf(beta)#-carbon relationship between the carbonyl on the right and the to-be-removed group on the left. Both reactions require that relationship.

CHALLENGE: Try drawing resonance structures to convince yourself that the #beta#-carbon relationship is favorable (that is a valid test question!). Additionally, try doing this with acetoformate instead of acetoacetate. You'll see that the carboxyl group lying on the #alpha#-carbon doesn't make it quite as favorable.