Addition of Amine Derivatives - Video Tutorials & Practice Problems

Brady's Reagent

There was a lot going on on that benzene molecule, but there was only one part of it that could react with the ketone, and that was the hydrazine. This is just a derivative of hydrazine. In fact, this molecule is actually called 2,4-DNP, and it's used as Brady's test. This is a molecule that you might actually use in your organic chemistry lab this semester because it's a very famous test for ketones. What happens is that when you make the phenylhydrazone product, that phenylhydrazone will precipitate out of the solution. And it usually precipitates in a yellow, orange, or red color. If you get that precipitate, you have a ketone present. This is actually a test that's used to detect ketones. Let's see what the phenylhydrazone product would look like. Well, we know that obviously I'm not going to draw the whole mechanism because that's not what this question is asking. Just asking to predict the product. I would go ahead and I would draw my imine. But I need to attach the hydrazone part. In fact, it's going to be a phenylhydrazone. I'm going to add NH. Let's see what else is attached to it. We've got a benzene ring. That benzene ring has 2 nitro groups, so let's add those. N2O2, N2O2 and that would be it. That's our molecule. This is basically a phenyl hydrazone. Hydrazone. In fact, it's a 2,4-dinitrophenylhydrazone because this is the 2,4-dinitro part, 2,4. Do you think you can figure out where the name comes from? It's 2,4-dinitrophenylhydrazone. That's why it's called 2,4-DNP. It's a great example of an imine derivative and it's actually a reaction that you might see later this semester. So if it comes up, you'll say, hey, I learned that at Clutch. Maybe you tell your lab partners that they'll know about Clutch too and more people know about us. Awesome. All right. So let's move on to the next topic.