Draw a Fischer projection for a D - 2 -ketoheptose. |...

Name: Problem 17, Chapter 20: Introduction to General, Organic and Biochemistry
Uploaded: 2020-07-14T04:29:32-08:00
Duration: 8 min 33 s
Channel: Megha Ramappan
Description: Draw a Fischer projection for a D - 2 -ketoheptose.

Key Concepts

Ketoheptose

A ketoheptose is a seven-carbon carbohydrate (heptose) that contains a ketone functional group, typically located at the second carbon atom, making it a ketose sugar. The presence of the ketone group affects the molecule’s reactivity and its stereochemical properties. In the context of Fischer projections, accurately positioning the ketone group and the hydroxyl groups on the remaining chiral centers is crucial for correctly representing the molecule’s structure.

Fischer Projection

A Fischer projection is a two-dimensional representation of a three-dimensional organic molecule—especially carbohydrates—that uses a specific arrangement of bonds around asymmetric carbons to depict stereochemistry. Vertical lines represent bonds going away from the viewer, while horizontal lines indicate bonds coming toward the viewer. It simplifies the visualization and comparison of stereocenters in complex molecules, providing a standard method to display the configuration of sugars and other biomolecules.

D-Sugar Configuration

The D-configuration in sugars refers to the stereochemistry of the chiral carbon farthest from the carbonyl group, which in most cases is the penultimate carbon in the carbon chain. In a Fischer projection, if the hydroxyl group on this carbon is on the right side, the sugar is designated as a D-sugar. This notation is essential in carbohydrate chemistry as it distinguishes enantiomers that have different biochemical properties.

Transcript

00:13 D2 keto heptose.

00:24 Now just looking at it, it may not seem like a lot, seem like a lot, but this name right here actually packs in a whole lot of information.

00:36 So to start, keto right there is telling us that there is a ketone group in this chain.

00:52 Okay.

00:53 And if we take a look over at, hept, this is telling us that it's a seven carbon chain.

01:07 Okay, so right now we know that we have a seven carbon chain and somewhere in there is a ketone group, but where? so, we are also given the number two.

01:24 Now, this is significant because this guy tells us the location.

01:32 Of the location of the ketone group.

01:39 And this location happens to be the second carbon.

01:44 So this is telling us that the ketone group is on the second carbon.

02:00 Cool.

02:01 Now our last piece of information is a letter d.

02:07 So d, simple enough, tells us that the oh group, on the penultimate carbon or the second to last carbon is on the right okay so this like i said this name gives us a lot of information so based on the name itself we can go ahead and make a seven carbon chain okay let's draw in black so so we have, we're going to scroll down just a little bit.

02:58 So we have one carbon, two carbons, three carbons, four carbons, five, six, and seven.

03:20 Okay.

03:21 So that's our seven carbon chain right there.

03:30 Okay.

03:32 And if i scroll up, we know that there is a ketone group and we know that the ketone group is on the second carbon.

03:42 So right here is our keytone group...

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