Propose a mechanism for the hydrolysis of benzaldehyde methyl ...

Question

Propose a mechanism for the hydrolysis of benzaldehyde methyl imine just shown.

Accepted Answer

All right. Hi everyone. So for this question we must draw a suitable mechanism for the acid catalyzed hydraulic sis of acid to hide method. I mean the reaction is shown below. And here we have our starting material being hydrolyzed into the corresponding AL to hide and our method to meet. So recall for a second that um that I means are very similar to car bottles. Right? So when you react ammonia or a primary amine with another hydra ketone with an AL to hide or a ketone that's going to generate what we call. I mean, which is very similar looking to a car bottle except we have the C double bond N instead of R C double bond. So that's the difference between I mean in a carbonnel and the hydraulics is of an I mean is essentially going to be the reverse of the mechanism for its formation. So our first step, because we're in acidic conditions. The first step is going to be the protein nation of our I mean via our asset of course. So are lone pair of the nitrogen is going to go ahead and snatch up a proton that's floating around in solution and we're going to end up with a pro donated I mean, Right, so this is our CH three and now our nitrogen is going to have an additional hydrogen and therefore a um a plus one charge. But nitrogen is not a fan of that. Right, So good thing is um is that residents as possible. And this double bond of the I mean can actually shift towards the nitrogen. Right. leaving nitrogen neutral and a Korbel cat eye on. So this is our end with our method group. And now, like I mentioned before, our nitrogen has that lone pair and we have a carbon cat eye on instead. So that caramel cat ion is actually going to go ahead and get um pro donated or rather attacked, I should say by a molecule of water. So this is water and water is gonna go ahead and attack this carbon cat eye on that we have over here. And so we are going to end up with this intermediate notice how now um we have a water molecule associated to this, I mean and oxygen has a positive charge because both hydrogen are still attached. So that positive charge on oxygen is now going to pose a problem. But that's okay right, because another molecule of water can go ahead and remove it. So if I go ahead and I draw another molecule molecule of water, then water is gonna go ahead and snatch up a proton from R. O. H. Two plus and I drew this arrow in the wrong color. So now we're gonna end up with a neutral O. H. Group instead. So this is our our nitrogen with our method group. And now, like I mentioned before, we have a neutral O age group. So now the second step is actually going to be the second proto nation um of the nitrogen. Right? So if I go ahead and I draw out another proton, then what's going to happen is that the lone pair of the nitrogen is going to go ahead and snatch it up. And so we're going to end up once again, right with a positively charged nitrogen. So let me go ahead and draw out our tetra hydro um intermediate. So this is our group. And now, like I mentioned before, or nitrogen is going to have an extra hydrogen and therefore a positive charge. So that's problematic, of course. But residents once again is possible residents once again um is possible because the nitrogen can actually go ahead and leave. Right, so our nitrogen here is going to go ahead and detach itself from this tertiary, sorry, this tetrahedron intermediate. And we're going to end up with a carbon copy. So this is gonna be our carbon in the center, right? And here's our wage group. And now, because the nitrogen has detached itself, we do in fact have a carbon cat, I'll, Right, so this is going to rearrange itself into a proton ated car bottle. So, if a pair of electrons from the oxygen here goes in between itself and the carbon, we're going to end up with a pro donated car bottle. Right, Because our um our oxygen is still going to have that hydrogen attached. And so we have a formal charge of plus one. So that can be fixed pretty easily by our water molecule, of course. So if we introduce yet another water molecule, then that's going to go ahead and generate a neutral car bottle now. So therefore um what we just did is regenerate are all the height. Alright, so this is going to be your final answer. And if you actually go ahead and you compare the steps of um of this hydraulic sis reaction um to the formation of an I mean you're going to notice that it's the exact opposite right? We're going backwards. So this is going to be it for the question. If you stuck around to the end, thank you so much for watching. And your answer is gonna be choice eight. So your answer is gonna be choice A And if you stuck around to the end, thank you very much for watching. And I hope you found this helpful.

Propose a mechanism for the hydrolysis of benzaldehyde methyl imine just shown.

Key Concepts

Imine Hydrolysis

Acid-Base Catalysis

Nucleophilic Attack

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