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Topic: A good THP-protection protocol for -OH  (Read 2674 times)

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Offline tdzeta

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A good THP-protection protocol for -OH
« on: August 01, 2014, 04:04:27 PM »
Problem: I tried TosOH/DCM protocol for THP-protection of my alcohol, but I always have a lot of impurities derived from DHP self-reaction. It is impossible to clean my THP-prptected alcohol from these by products by cc-sg

Question: Could you share a good protocol which can yield a clean THP-protected alcohol without the impurities?

Thank you in advance!  :)

Offline AlphaScent

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Re: A good THP-protection protocol for -OH
« Reply #1 on: August 04, 2014, 11:15:24 AM »
What is your compound structure?

What other functional groups are present?
If you're not part of the solution, then you're part of the precipitate

Offline tdzeta

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Re: A good THP-protection protocol for -OH
« Reply #2 on: August 05, 2014, 04:43:31 PM »
It is not important. It has only one naked -OH and by-products are from DHP self condensation. I am going to reduce temp. down to 0°C or so on. I feel this should help as  DHP reacts with -OH much faster than with DHP.

Offline orgopete

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Re: A good THP-protection protocol for -OH
« Reply #3 on: August 05, 2014, 06:00:00 PM »
I don't know the answer to your question, but as an experimentalist, if I was observing self condensation of my reagent, I'd reduce the stoichiometry or I'd add it slowly.
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Offline PhDoc

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Re: A good THP-protection protocol for -OH
« Reply #4 on: August 06, 2014, 10:58:51 PM »
Why are you using THP group?

Benzyl, BOM, MEM, MOM, TBS, TBDPS, SEM... see Theodora Greene
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Offline tdzeta

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Re: A good THP-protection protocol for -OH
« Reply #5 on: August 07, 2014, 12:31:08 PM »
I use THP because it is hard to de-protect this -OH (if other protective group is used) and the protection is required as the reaction condition is way too hard for this molecule to survive.

The Green's book is a great one but I did not find  any information about DHP by-products I see in my reaction mixture in there. It should be ascribed-discussed somewhere I believe, but I still could not find such paper etc.

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