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Topic: Basic amide hydrolysis  (Read 2482 times)

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Offline kriggy

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Basic amide hydrolysis
« on: March 05, 2015, 09:58:59 AM »
Hi there,
how many equivalents of hydroxide is required for basic amide hydrolysis? I wrongly calculated the mass of hydroxide and have added only 3 equivalents instead of 9 as the procedure wanted. Im just thinking if it will run  into complete deprotection or not. Is it possible that it will complete but at slower rate?
Thanks

Offline TheUnassuming

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Re: Basic amide hydrolysis
« Reply #1 on: March 05, 2015, 05:49:10 PM »
In theory it should be fine, just slower perhaps.
When in doubt, avoid the Stille coupling.

Offline orgopete

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Re: Basic amide hydrolysis
« Reply #2 on: March 06, 2015, 01:22:49 AM »
It depends. The intermediate is a dianion. If three equivalent instead of nine but 1/3 volume, may not be as bad, but if you have diluted the solution, I think you may greatly slow the reaction as it will become more difficult to form the needed dianion.
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Offline kriggy

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Re: Basic amide hydrolysis
« Reply #3 on: March 06, 2015, 12:52:20 PM »
Thanks. It wenr OK however after 20 hrs there are still traces of starting material so I did it again with the correct amount of hydroxide and it went to full deprotection after about 3,5 hours while forming maybe 1-3% of side product which I can get rid of in next steps.

PS: While refluxing hydroxide dont forget to use some silica oil or fat or whaterver you are using in a lab on glass joints. Otherwise, it will melt the joints together. And its embarassing when it happens. (At least I got cool new piece of glasware  ;D )
« Last Edit: March 06, 2015, 03:50:52 PM by kriggy »

Offline TheUnassuming

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Re: Basic amide hydrolysis
« Reply #4 on: March 06, 2015, 02:54:23 PM »
PS: While refluxing hydroxide dont forget to use some silica oil or fat or whaterver you are using in a lab on glass joints. It will melt the joints together. And its embarassing when it happens. (At least I got cool new piece of glasware  ;D )

haha... I hadn't even thought about that.  Live and learn I suppose :P.
When in doubt, avoid the Stille coupling.

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