LiAlH4 question with reduction

[BiomajorPreDent]

Now I dont know if this is overkill for the DAT..but on destroyer question 93 (2009 edition) it shows a nitrile being reduce to a primary amine and it asks which reagent is used.

Now I know its LiAlH4, but destroyer says never use it in H2O as you will blow yourself up. Its supposed to be used in Diethyl Ether with H3O..

Ok, but in my text for the nitrile reduction it just says LiAlH4..so its not as specific as destroyer is being

but my text also says that for a reduction of Amides you would use LiAlH4 with water in the second step and not acid..

So are there certain times you use water and certain times you use acid?

Again, I dont know if this is overkill, on the DAT it would just say LiAlH4 or another reagent..but I want to be prepared.

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[MTD52]

Yeah I think you're in the overkill department here.

You know that LAH reduces nitriles and amides to amines. That's probably all that you'll need to know. Just my opinion.

Plus, I think water acts as an acid in the second reaction you referred to anyway, no?

 

[BiomajorPreDent]

yeah..I agree with you..but these details are getting really annoying now

because in the explanation for question 106 in destroyer it shows a nitrile being reduced to a primary amine with LiAlH4 and Diethyl ether and WATER!!!!

whats going on???????

 

[MTD52]

Just settle down. Know that LAH + nitrile/amide = amine. That should cover it. I know what you're saying with Destroyer and that could make it confusing, but the reactants of diethyl ether and water are both usable.

 

[loveoforganic]

The deal is LAH reacts violently with water. This is only really an issue if you use a lot of excess LAH or something, so you have a lot leftover when it's time to quench the reaction. I would guess that's overkill knowledge.