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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Urbanium on September 02, 2019, 09:00:45 AM

Title: Hydrogen-deuterium exchange
Post by: Urbanium on September 02, 2019, 09:00:45 AM

How likely it is a H/D exchange will take place in a basic aqueous solution if the dissolved deuterated compound contains deuteriums only at alkyl groups (i.e. -CD₃, -CD₂-, -CD--)? I'm familiar with exchange at -OH and -NH groups, but does that occur with deuterated alkyl groups?

Title: Re: Hydrogen-deuterium exchange
Post by: Babcock_Hall on September 02, 2019, 09:47:14 AM

Is there a functional group next to the carbon in question?

Title: Re: Hydrogen-deuterium exchange
Post by: Urbanium on September 02, 2019, 10:13:02 AM

Quote from: Babcock_Hall on September 02, 2019, 09:47:14 AM

Is there a functional group next to the carbon in question?

There are hydroxyl groups only, more precisely a --CD-OH  and also one -CD₂-OH further away.

Title: Re: Hydrogen-deuterium exchange
Post by: Babcock_Hall on September 02, 2019, 10:21:23 AM

When a ketone group is in the alpha position relative to a -CH_x group of some kind, basic exchange is expected.  Do you think that a hydroxyl group would have the same effect?  Why or why not?

Title: Re: Hydrogen-deuterium exchange
Post by: hollytara on September 02, 2019, 12:22:24 PM

Carbonyls can undergo acid catalyzed exchange too. 

What is the pKa of the protons next to a hydroxyl?