24. Carbohydrates
Monosaccharides - Weak Oxidation (Aldonic Acid)
We explored that as polyols with carbonyls, monosaccharides can undergo a series of oxidation and reduction reactions. One of those possible oxidations is called Weak Oxidation. Let's learn more about this process.Â
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concept
Monosaccharides - Weak Oxidation (Aldonic Acid)
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in this video, we're gonna learn how to perform a week oxidation on mono sack rides. Thio yield a functional group called Al Danek acid. Let's get going. So, guys, mano sack rights are essentially Paulie alls with carbon meals attached or with one carbondale attached. So that means that they can undergo a Siris of oxidation and reduction reactions. Because we have so many reactive, functional groups, we have alcohols that could be oxidized. We have key tones that could be reduced all kinds of stuff. Okay, well, it turns out that one of those possible oxidation is called week oxidation. And what week oxidation is to find us? It's the selective oxidation off mano sacha ride. Alga hides to car bucks Cilic acid. Okay. The selective oxidation of just the alga high to carve oxalic acid is known as weak oxidation. Now, guys, think about it. All of these different Ohh is could potentially be oxidized. They could be this so it could be oxidized to a key tone. This O. H is a primary alcohol that could totally be oxidized to a carb oxalic acid. If I use ah strong enough oxidizing agent, I could turn this whole thing into key tones, carb, oxalic acids, etcetera. But with the special with a special oxidizing, Agent Aiken simply just select the very top alga hide and turn it into a carb oxalic acid. Okay, In fact, this reaction doesn't even work with ketosis because ketosis don't have Aldo hides, right? So it's selective for Aldo hides to carve oxalic acids. And the re agents that we use for this are actually just called bro mean water. Okay, so it's bro Ming in water. This method can be used to differentiate between all doses and key toes is because it doesn't work on ketosis. You can't do anything with them. It works on all doses, but it doesn't work on Keto, so it's kind of the basis. The principle of this is the basis for some tests of, um, of sugars, some sugar test to test whether you have one type of function group or another. This is kind of like one of the tests. OK, now, guys, we're in luck. The mechanism of this reaction of this oxidation is not fully known. So you're not gonna have to draw the mechanism. You just need to be aware of what these regions do and what the product is. So let's go through it really quick. Here. I have de manos sugar you guys should be super familiar with. I'm going to react it with bro. Mean water now, specifically, it should be mildly, mildly acidic. It shouldn't just be bromate and water to be a little bit acidic, but just you guys know most textbooks. Most. Most professors skip this part, they don't even write it. I'm just putting this here for your benefit. So you guys know? But in the future, I'm going to skip the Ph six part because most texts and professors don't use it. Okay, What this is going to do through a mechanism that we don't fully know, it's going to selectively Onley oxidize my Aldo hide to a car bucks like acid and notice that no other groups are going to change even the primary alcohol stays totally is fine. The only thing that oxidizes is the top. Okay, when this happens, the functional group is no longer called a um it's no longer like a mono sack, right? It's It's a modified model sack right called an al Danek acid. So what you would do is you would take your route, which is de manos. So you take the D man apart and you would add on the Suffolk's of nick acid because notice that it's a nick acid al Danek acid, so you would just end. Add on the nick acid part. And that's the way that you would name it. So a an al Danek acid of demand asses specifically called demon onek acid. And that means that I have a d manos that oxidize the top to a carb oxalic acid. Okay, cool. So that's it for that general reaction. Let's go ahead and do a practice problem.
General Reaction:

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Problem
ProblemPredict the product of the following reaction.
A
B
C
D