You answered a earlier post on a question for someone with the same question I am trying to answer.
The hydrolysis of tocainide
you stated only the NH2 group hydrolyses NH2 + HOH -> NH3^+ OH^-
I understand that part but I need to understand why the amimine only hydrolyses. Am I to understand that the amide part is unchanged and if so why?
I will try and recreate the structural formulae as best I can
Benzene ring with 2 CH3 attached. One N attached to ring. N has a C attached and one H to it. The C attached to the N is attached to a CH which in turn has a CH3 and a NH2 attached to it.
So, there is a amide and a amine here.
I don't understand enough about hydroysis yet. I can work it out OK with one functional group but have trouble when there is more than one. If the amide hydroysed then I would get a acid and a alcohol. Somewhere along the line I have missed something don't like answering anything without understanding it properly. I would be very grateful for your help me once before and put it over clearer than my tutor.
It's tough to draw structures, or even describe them, on the computer. I looked up the structure of tocainide in my home copy of The Merck Index.
Amines are basic and, by the Bronsted-Lowry theory, accept protons from water. Reaction with water is hydrolysis. Amines usually are basic enough that they require nothing more than addition of water to react. Amides are neutral. The -CONH2 (amide) group CAN be hyrolyzed but it is tougher to do so. Under (usually) high acidic conditions (such as strong HCl), the -CONH2 group forms NH3 + the corresponding RCOOH acid and those two react to form the ammonium salt (RCOO^- + NH4^+). Under (usually) high basic conditions (such as NaOH or KOH), the RCOO^- + NH4^+ salt is formed directly without going through the intermediate steps. The way I understood the problem, it was a simple hydrolysis withough strong acid or alkali present. I hope this helps.
Thank you very much for taking the time to help me
You're welcome! I'm glad I could help. Hydrolysis is a chemical reaction that involves breaking a chemical compound apart using water. In the case of tocainide, only the NH2 group (amine group) undergoes hydrolysis. This is because amines are more basic compared to amides. The amine group acts as a nucleophile and reacts with water, accepting a proton (H+) from water to form NH3+ and OH- ions. The amide group, on the other hand, remains unchanged because it is more stable and not as reactive as the amine group.
To understand why the amide group does not undergo hydrolysis, it's important to consider the functional group itself. The amide group (-CONH2) consists of a carbonyl group (C=O) and an amino group (NH2) bonded to the same carbon atom. The carbonyl group in amides is less reactive compared to the nitrogen atom in amines. The oxygen atom in the carbonyl group is more electronegative and stabilizes the negative charge on the carbon atom. This makes the carbon less susceptible to attack by water molecules and therefore less likely to undergo hydrolysis.
In summary, the amine group in tocainide undergoes hydrolysis because it is more basic and reactive compared to the amide group. The amide group remains unchanged because it is more stable and less reactive towards hydrolysis.