Reduction of Monosaccharides - Video Tutorials & Practice Problems

Reduction of Monosaccharides Concept 1

Now, when it comes to the reduction of an aldose or keto sugar, we're gonna say the carbel group is reduced via reducing agent to a hydroxyl group to create a sugar alcohol. Now, when I say hydroxyl group, I just mean an o age group, a sugar alcohol is just a monosaccharide that has all carbons connected to a hydroxyl group. Now, when it comes to this reduction, the reducing agent is age two and the reduction is facilitated by the use of metal catalysts in the form of nickel platinum or palladium. What happens in this reaction is that our carbon oxygen gains an H and the carbon carbon also gains an in. So we go from an aldose or keto sugar to our sugar alcohol.

Reduction of Monosaccharides Concept 2

So let's look and see what this reduction of mono sac rides would resemble. If we take a look here, we have an all sugar to begin with and we're gonna say we're reducing it with H two with one of our metal catalysts, nickel palladium or platinum. Remember the carbon carbon will gain an inch and this carbonyl oxygen is still present and it also gains an inch. And in that way, we've gone from an alto sugar to just a sugar alcohol. Now let's look at our keto sugar. Same thing we're using H two with one of our three metal catalysts. We're gonna say here that are carbon carbon gains in H and then the carbonyl oxygen is still present. It also gains an inch. And again, we've created a sugar alcohol this time from a ketose sugar. So remember we're making sugar alcohols because now all the carbons within this structure have an oh connected to it, right? So just keep that in mind, we're going from an Aldo sugar to a keto sugar. Our carbonel group is being transformed into ac oh group

Reduction of Monosaccharides Example 1

He says the term the sugar alcohol product form from the reduction of the following monosaccharide. So here's our monosaccharide which is a keto sugar. Remember in its reduction, it's the carbon carbon or the carbonel group that's being transformed. We're going to say here that that carbon carbon gains in and the carbon oxygen is still there. It also gains an inch and then the rest of the structure stays the same. So we'd still have this C with an H here in an oh here this scene with an oh year and an H year and then our C H2O H group. So this would be our sugar alcohol product formed from the reduction of this ketose sugar.

Determine which aldose reactant should be used to produce the following sugar alcohol.

• A.
• B.
• C.
• D.

Common Naming of Sugar Alcohols Concept 3

So we know the reduction of an aldose or keto sugar, create a sugar alcohol. With this, we have to be able to name the sugar alcohols. Now we're gonna say the common naming of sugar alcohols is the set of rules for naming them are similar to aldose and keto sugars. Now, the way we do it is we modify the ending of our aldose or keto sugars which typically end with O and we change it to I talk all because it's an alcohol. So remember when we're going, when we have an aldose or keto sugar, their ending is O when they get reduced to a sugar alcohol, the ending transforms to it to.

Reduction of Monosaccharides Example 2

Here it says provide the structure and common name for the sugar alcohol created from the reduction reaction. So here we're starting out with D ribose and we know that when it comes to reduction, we're reducing the aldehyde group. I remember the, all the high group is C double bond O connected to an H. When it comes to reduction, the carbon carbon would gain an inch and the carbon oxygen which is still there would also gain an inch. This would transform the alde group into AC H2O H group. So we're gonna have C H2O H now and the rest of the structure would stay the same. So we still have this carbon connected to oh and H and same with the other two and then ch two A H here on the bottom. Remember when it comes to naming the common naming of sugar alcohols, we change the O ending to it to. So this would be called D Ryba. This would be the common name of this sugar alcohol.

What is the common name of the sugar alcohol produced when D-galactose is reduced?

• A. L-galactose
• B. D-galactitol
• C. D-galactaric acid
• D. L-galactitol

Draw the Fischer projection for the reduction product of D-mannose, the C-2 epimer of glucose. What is the structure and common name of the sugar alcohol produced? 

• A.
• B.
• C.
• D.