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Topic: Chiral Centers in Cholesterol  (Read 33598 times)

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Offline NoCode.

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Chiral Centers in Cholesterol
« on: February 05, 2008, 06:18:35 PM »
When I went to find the chiral centers in cholesterol, I found 7 of the 8. Why is the circled carbon a chiral center? It looks to me that it is bonded to 2 of the same molecule.



Thanks.
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Offline macman104

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Re: Chiral Centers in Cholesterol
« Reply #1 on: February 05, 2008, 06:22:42 PM »
It does?  You have to look past just the direct carbon it is attached to also.  I think you'll see that it is not in a symmetric position at all.  For example, they both connect to a CH, but after that, the paths differ.
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Offline agrobert

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Re: Chiral Centers in Cholesterol
« Reply #2 on: February 05, 2008, 06:23:25 PM »
Refer here for numbering.

http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=stryer.figgrp.3660

C-8 (circled) has a hydrogen going back (into the plane) and is connected to four different substituents.  Chirality has to do with symmetry and C-8 is not a symmetric center.  C-14 which you knew was chiral is chiral for the same reason as C-8.
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Offline agrobert

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Re: Chiral Centers in Cholesterol
« Reply #3 on: February 05, 2008, 06:24:42 PM »
It might help to draw the stereochemistry of all centers including protons.
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In the realm of scientific observation, luck is only granted to those who are prepared. -Louis Pasteur

Offline NoCode.

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Re: Chiral Centers in Cholesterol
« Reply #4 on: February 05, 2008, 06:37:10 PM »
Thanks a lot. I wasn't thinking and didn't look past the direct carbon that it was attached to.
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Offline lucky09

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Re: Chiral Centers in Cholesterol
« Reply #5 on: September 30, 2009, 05:41:53 PM »
wait why is  C attached to HO a chiral???? ???
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Offline sjb

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Re: Chiral Centers in Cholesterol
« Reply #6 on: September 30, 2009, 05:44:53 PM »
Quote from: lucky09 on September 30, 2009, 05:41:53 PM
wait why is  C attached to HO a chiral???? ???

Because ultimately it's attached to 4 different groups (in this case). What is it attached to?
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Offline lucky09

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Re: Chiral Centers in Cholesterol
« Reply #7 on: September 30, 2009, 05:47:39 PM »
well one side is attached OH and two sides are attached to CH2 and one side H? rite
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Offline sjb

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Re: Chiral Centers in Cholesterol
« Reply #8 on: October 01, 2009, 02:03:29 AM »
Quote from: lucky09 on September 30, 2009, 05:47:39 PM
well one side is attached OH and two sides are attached to CH2 and one side H? rite

At "radius" one atom, yes, how about further out? Do you appreciate why the circled atom is chiral?
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