Wedge-and-dash Molecular Structures in 2-dimensions

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Discussion Overview

The discussion revolves around the challenges of accurately drawing a wedge-and-dash, two-dimensional molecular structure for Vitamin C (ascorbic acid), focusing on the representation of stereochemistry and the inclusion of all relevant atoms.

Discussion Character

  • Homework-related
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses difficulty in finding complete diagrams of Vitamin C that include all carbon, hydrogen, and oxygen atoms, as well as proper wedge-and-dash representations.
  • Another participant explains that stereochemistry is typically shown for specific carbons that exhibit stereochemistry, noting that ascorbic acid has two stereocenters.
  • The second participant describes how the stereochemistry is represented in existing diagrams, indicating which groups are wedged or dashed.
  • A third participant shares their attempt at drawing the structure and seeks feedback on its accuracy.
  • A fourth participant critiques the third participant's drawing, pointing out that the stereochemistry around a specific carbon is unclear due to the incorrect representation of the hydrogen, hydroxyl, and lactone ring all being wedged.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct representation of the stereochemistry in the drawing, as there are differing interpretations of how to depict the molecular structure accurately.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the stereochemistry and the clarity of the diagrams being referenced. The discussion also highlights the challenge of interpreting 3D models for 2D representations.

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Homework Statement


I'm having trouble drawing a wedge-and-dash, 2 dimensional molecular structure for Vitamin C (ascorbic acid). All of the diagrams I've looked at (on the Wikipedia page, and some .edu websites) are incomplete: they either don't include the carbon and/or hydrogens molecules, or the wedges and dashes

Homework Equations



none.

The Attempt at a Solution



I've tried drawing it based on other diagrams found on the internet, but they are all incomplete (none of them actually inclde C6H8O6 (6 carbon, 8 hydrogen, and 6 oxygen). As I said earlier, the creators of the 2d diagrams often omit some of the carbons and hydrogens, or don't put in the wedges/dashes.

I've also tried looking at 3d models to figure out when wedges and dashes should be put in, but its hard to tell whether or not the angle of the bond is coming towards you, away from you, or neither one.

I've mostly been using this website to try and figure out how to do this.

http://www.3dchem.com/molecules.asp?ID=69#
 
Last edited:
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The stereochemistry you are asking about usually is shown only for select carbons... the ones that exhibit stereochemistry. In ascorbic acid there are two stereocenters. One bears a hydroxyl and the other is attached to the lactone ring. The hydrogen at that carbon is dashed in the Wiki drawing. Since the hydrogen is dashed, the carbon of the side chain (not the cyclic structure) is assumed to be wedged. It is difficult to show the absolute stereochemistry about that carbon by wedging the 2 carbon side chain but it is wedged nonetheless.

The stereochemistry about the adjacent carbon bearing the hydroxyl shows the OH group as being wedged. The hydrogen attached to the same carbon is not shown but is assumed to be dashed.
 
Thanks for your help! I wasn't familiar with a lot of the terminology you used (sophomore in high school) but I think I mostly understood what you were saying. Here's what I came up with (let me know if I got it right/wrong):
http://img691.imageshack.us/img691/7160/2ddrawing.png
 
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I can't decipher the stereochemistry around the carbon bearing the OH on the side chain. You have the hydrogen, hydroxyl and the lactone ring all wedged. This means that they are all coming up out of the plane of the drawing. This makes understanding the stereochemistry about that carbon impossible.
 

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