All the steps up to the point of NH3 leaving are in equilibrium. But once the NH2 is protonated to NH3 and the NH3 leaves, acid will turn it into NH4+ and the reaction is essentially irreversible at that point.

The amide is an intermediate en route to the acid. If mild enough conditions are used, the amide can be isolated.

Imine with boronic acid gives aryl amino acids without palladium and base

Mosers acid can be used during amino acid synthesis
Ammonium cyanide aldehyde and Moser acids instu to prepare chiral pure amino acids backbone .

Reaction of imidazole azide with malonic acid to give diazido compound can that be reduce to amino functionality. Ester can be funtiinalized
I don’t know if I want to ask question suggested or that i m giving inputs .

Can I get review of enzymatic reaction preparing aminoacids.