Lactulose is a disaccharide used in the treatment of chronic constipation. Its formal name is galactose β(1→4) fructose.
(a) Draw the structure of lactulose.

Question

Lactulose is a disaccharide used in the treatment of chronic constipation. Its formal name is galactose β(1→4) fructose.

(a) Draw the structure of lactulose.

Accepted Answer

All right. Hello everyone. So this question says that the formal name of Isom Moose, a disaccharide used as a slow digesting carbohydrate in food products is glucose, alpha 16 fructose provide the structure of isom modulo. So because we know that this compound Isom Moose is a disaccharide, we know that it's composed of two monosaccharide units held together by a glyco cytic bond. Now, the mono sac rides in question if you recall or glucose and fructose based on the formal name given. So first, let's go ahead and recall the structures of these monosaccharide separately before discussing how to go about drawing their glyco cytic bond. So let's start with glucose. Now, based on the formal name given, we know that we have to start by drawing out the Hayworth projection of alpha D glu copy nose, right? So this is the cyclic form of alpha D glucose. So here it's a six membered ring with the anomic carbon having a hydroxy group pointing downwards because it is in the alpha configuration. So lets start by drawing out the six member ring. So here we call that by convention, right? The oxygen that makes up the ring is depicted on this top right corner. Whereas carbon number one, the anomic carbon is on the far right side. So here I'm just adding some shading to show dimensionality. So now let's go ahead and start with carbon number one, right as mentioned before, because this is the alpha ener of D glucose. The hydroxy group on carbon number one should be pointing downwards, which means that the hy the hydrogen in that position should point upwards. So on carbon number two, the hydroxy group is going to once again point downwards. So the hydrogen points upwards on carbon. Number three, we have the hydroxy group pointing upwards and the hydrogen pointing downwards. For carbon number four, we have the hydroxy group pointing downwards and hydrogen pointing upwards. Now, for carbon number five, it's the hydroxy group of carbon number five that is creating the ring in the first place. So from carbon number five, its hydrogen should be pointing downwards and carbon number six which is a primary alcohol should be pointing upwards. So above the rank. So here we have the structure of alpha D glu copy. So at this point, let's go ahead and go about drawing the other mono sac right here. The other monosaccharide is going to be beta D fructose. This is because fructose if you recall is going to form a five member ring and it's going to be in the beta configuration in this particular case to ensure the proper glyco cytic bond with our glucose unit. So let's start by drawing that five membered ring. So once again, I'm just adding some shading in the front here, just the show three dimensionality. So now let's go ahead and start with carbon number one. Now, as mentioned before, because this is the beta ener the hydroxy group of carbon number one should point upwards. Now because fructose has an additional carbon outside of the ring, that additional carbon is actually connecting to carbon number two or rather carbon number one of the ring and is pointing downwards. So on carbon number two of the ring, we have the hydroxy group pointing upwards and hydrogen pointing downwards for the third carbon of the ring, we have hydroxy group downwards and hydrogen upwards. And then from the fourth carbon of this ring, we have another ch two oh pointing upwards, turn hydrogen pointing downwards. So now let's go ahead and go about our glyco cytic linkage as mentioned before. This is an alpha 16 glyco cytic bond. This means that the bond is going to be formed between the anomic carbon that is carbon one of glucose and carbon number six of fructose. Now keep in mind that carbon number six is this primary alcohol carbon that is above the ring itself. So the first thing I'm going to do is bring these monosaccharide units closer together. And some modifications need to be made for the glyco cytic bond to be depicted. So first and foremost, I'm going to remove the hydrogen from the hydroxy group of glucose is anomic carbon and carbon number six of fructose is no longer going to have its hydroxy group either. So here I'm going to bring these mono sac rides a little closer together and then I'm going to draw a bond between these atoms and there you have it. Now we have the completed structure of I saw motul. And so with that being said, thank you so very much for watching. And I hope we found this helpful.

Lactulose is a disaccharide used in the treatment of chronic constipation. Its formal name is galactose β(1→4) fructose.
(a) Draw the structure of lactulose.

Verified video answer for a similar problem:

Key Concepts

Disaccharides

Glycosidic Bond

Chemical Structure Representation

Lactulose is a disaccharide used in the treatment of chronic constipation. Its formal name is galactose β(1→4) fructose.(a) Draw the structure of lactulose.

Verified video answer for a similar problem:

Key Concepts

Disaccharides

Glycosidic Bond

Chemical Structure Representation

Lactulose is a disaccharide used in the treatment of chronic constipation. Its formal name is galactose β(1→4) fructose.
(a) Draw the structure of lactulose.