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Topic: Is SOCl2 needed?  (Read 3553 times)

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Offline rentj

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Is SOCl2 needed?
« on: May 01, 2024, 04:01:12 AM »
Is the first step of adding SOCl2 needed for this synthesis? Because the excess LAH in the second step will do the same thing, which is producing a primary alcohol. Thank you

Offline Babcock_Hall

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Re: Is SOCl2 needed?
« Reply #1 on: May 01, 2024, 07:43:17 AM »
I am not sure what would happen if you left out the thionyl chloride.  If you are following a literature preparation, I see no reason to deviate from it.

Offline Hunter2

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Re: Is SOCl2 needed?
« Reply #2 on: May 01, 2024, 03:33:29 PM »
I think with the Thionylchloride you create first the cyclopentylcarboxylchloride, this should be reduced to the aldehyde to obtain in the end the Acetale. If you get total reduction to the cyclopentylmethanol then it is not possible to fo further.

Offline rolnor

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Re: Is SOCl2 needed?
« Reply #3 on: May 02, 2024, 03:01:09 PM »
I think with the Thionylchloride you create first the cyclopentylcarboxylchloride, this should be reduced to the aldehyde to obtain in the end the Acetale. If you get total reduction to the cyclopentylmethanol then it is not possible to fo further.

But there is PCC in the reagent list, do you know what that is for? Can you reduce an acid chloride to aldehyde with LAH?

Offline Hunter2

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Re: Is SOCl2 needed?
« Reply #4 on: May 03, 2024, 05:19:37 AM »
It's an oxidiser. To oxidise Alkohol to Aldehyde. Yes with LAH the Reduction goes direction to the Alkohol.
But if so then LAH can be used to refuse the carbonic acid. Maybe SOCl2 is only used to remove water.

Offline Babcock_Hall

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Re: Is SOCl2 needed?
« Reply #5 on: May 03, 2024, 08:52:42 AM »
@OP, Is this a homework assignment, or are you doing this reaction in a laboratory?

Offline rolnor

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Re: Is SOCl2 needed?
« Reply #6 on: May 04, 2024, 12:49:25 AM »
It's an oxidiser. To oxidise Alkohol to Aldehyde. Yes with LAH the Reduction goes direction to the Alkohol.
But if so then LAH can be used to refuse the carbonic acid. Maybe SOCl2 is only used to remove water.

The acid chloride is reduced to alcohol, then oxidised to aldehyde. It's not common to reduce a carboxylic acid to a alcohol with LAH i think. I have never seen this, I don't think it's possible.

Offline Hunter2

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Re: Is SOCl2 needed?
« Reply #7 on: May 04, 2024, 02:13:01 AM »

Offline Babcock_Hall

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Re: Is SOCl2 needed?
« Reply #8 on: May 04, 2024, 12:54:19 PM »
@OP,
Can you explain why an acid chloride is easier to reduce than an acid using fundamental concepts from organic chemistry?

Offline rolnor

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Re: Is SOCl2 needed?
« Reply #9 on: May 05, 2024, 01:16:23 AM »
In this Chart its possible

https://upload.wikimedia.org/wikipedia/commons/thumb/3/30/LAH_rxns.png/550px-LAH_rxns.png

Yes, I was not 100% sure. Maybe you need to boil the solution for some time

Offline rolnor

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