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Topic: Subsituition  (Read 1942 times)

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Offline Super Newb

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Subsituition
« on: August 28, 2012, 06:28:09 AM »
I am looking at the following substitution reaction:

The answer suggested me to use KCN/HCl or H2SO4, and I am wondering why is there a need for the acid. Why can't we just use KCN?
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Offline discodermolide

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Re: Subsituition
« Reply #1 on: August 28, 2012, 08:28:22 AM »
Quote from: Super Newb on August 28, 2012, 06:28:09 AM
I am looking at the following substitution reaction:

The answer suggested me to use KCN/HCl or H2SO4, and I am wondering why is there a need for the acid. Why can't we just use KCN?

With acid you will generate HCN, which makes the procedure more dangerous.
Just use KCN in DMSO at around 80°C.
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Offline orgopete

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Re: Subsituition
« Reply #2 on: August 28, 2012, 02:59:07 PM »
Quote from: Super Newb on August 28, 2012, 06:28:09 AM
I am looking at the following substitution reaction:

The answer suggested me to use KCN/HCl or H2SO4, and I am wondering why is there a need for the acid. Why can't we just use KCN?

Don't add acid. As written, it looks like an error. If one is trying to isolate the carboxylic acid, then HCl could be used in a second step.
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