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Topic: Kishner-Wollf reacrion  (Read 1968 times)

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Offline kriggy

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Kishner-Wollf reacrion
« on: January 26, 2016, 10:21:09 AM »
Hello guys, I was wondering anyone run this reaction?
I know, that in the "classic" variation, the nitrogen from hydrazone leaves as gas, but I saw wariations using tosylhydrazone for example. Does the nitrogen also leave as a gas ? Im trying to hydrolyze hydrazone into the hydrazin derivative and so far i was not succesful.Mostly there is a problem that the hydrazon is not soluble in acidic enviroment unless I heat it a lot in something like DMF or DMSO and then i get some random by-products but not the hydrazine.
So far, the procedure was to diazotate the amino derivative, and trap it with malononitrile, then Im trying to hydrolyze the hydrazono-dinitrile (or whatever it is called):

Offline phth

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Re: Kishner-Wollf reacrion
« Reply #1 on: January 27, 2016, 02:36:26 AM »
The tosyl hydrazone just acts like hydrazine with a more labile proton.  It is milder than the WK reduction which is quite harsh conditions required.  I think you are refering to the Shapiro Reaction https://en.wikipedia.org/wiki/Shapiro_reaction 
I would think that the hydrolysis would go better in acetonitrile(aq)/DMF(aq).  I would try to make the concentration dilute because hydrolysis is inversely correlated to hydrolysis; the relative stabililty of R may interfere.  Not sure.  Good luck

Offline kriggy

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Re: Kishner-Wollf reacrion
« Reply #2 on: January 27, 2016, 09:21:35 AM »
So if I understand you right: you are suggesting to make the reaction as dilute as possible ok? Also, why do you think that ACN would be better solvent?

Offline phth

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Re: Kishner-Wollf reacrion
« Reply #3 on: February 03, 2016, 02:36:33 AM »
Sorry for the late response.  Maybe this works if your compound is soluble in water.  DOI: 10.1021/acs.bioconjchem.5b00611
If not, then I would think a condensation reagent such as a phosphorus containing compound.  From my preliminary searches, I could not find anything relating to azido reduction to hydrazine.  I was thinking that may be another way to the product.  Possibly the  I2 PPh3 system may work.  I'd give it a search because I couldn't find anything obvious from Google only.  What i meant by it acting like a proton is that the tosyl group is more labile than a proton.

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