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Topic: TLC stain for alkyne  (Read 7434 times)

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Offline nkenton

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TLC stain for alkyne
« on: February 08, 2012, 07:42:43 PM »
Hey, all:

I am trying to develop a TLC staining solution for a terminal alkyne on an amino acid analogue.  I am looking to stay away from strong oxidants.

I read about a reagent called tetracyanoethylene... does anyone know if this is reactive towards terminal alkynes?

Offline Doc Oc

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Re: TLC stain for alkyne
« Reply #1 on: February 09, 2012, 12:06:43 AM »
Why are you avoiding oxidants?  KMnO4 would work great on an alkyne.  On the amino acid portion, is there a protecting group on the amine?  If not (or if it's a Boc group), you can use ninhydrin.

Offline Honclbrif

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Re: TLC stain for alkyne
« Reply #2 on: February 09, 2012, 12:42:48 PM »
You're really limiting yourself if you avoid oxidants. As Doc Oc said, KMnO4 is really the best stain for alkynes. They turn yellow/brown without any heat whereas other functional groups tend to require heat to develop.
Individual results may vary

Offline Babcock_Hall

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Re: TLC stain for alkyne
« Reply #3 on: June 01, 2012, 04:09:41 PM »
Doc Oc,

Does your reply mean that the conditions of the ninhydrin assay remove the BOC group?  Does it depend on whether or not the formulation of the TLC spray has acid?  Thanks.
« Last Edit: June 01, 2012, 04:56:06 PM by Babcock_Hall »

Offline Doc Oc

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Re: TLC stain for alkyne
« Reply #4 on: June 02, 2012, 01:29:09 AM »
It's not the ninhydrin, it's the heat used when you develop the stain.  It causes the Boc to decompose and release free amine.

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