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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: zuriel on August 21, 2013, 09:40:16 AM

Title: Amount of Hydrazine Hydrate in Wolff Kishner Reduction.
Post by: zuriel on August 21, 2013, 09:40:16 AM

Hi everyone,

I'm following an experimental procedure from this paper:

http://mend.endojournals.org/content/23/5/640.long

for compound X (p. 645) and I have a question about the AMOUNT of hydrazine hydrate used. They use 16.7 g of 85% hydrazine hydrate and, for me with 4 g of starting material using 60% hydrazine hydrate, it works out as 34.5 g (34 mL approx.).
I'm concerned about using this much of it though. Does anyone know WHY so MUCH is used? Is it necessary?

Title: Re: Amount of Hydrazine Hydrate in Wolff Kishner Reduction.
Post by: discodermolide on August 21, 2013, 09:50:38 AM

Work out the quantities in number of moles of both SM and hydrazine hydrate.

Title: Re: Amount of Hydrazine Hydrate in Wolff Kishner Reduction.
Post by: kriggy on August 28, 2013, 01:30:44 PM

Its about 8 times excess of hydrazine if I´m not wrong. I guess its because you want to have as little as possible of unreduced reagent. It seems that it also deprotects those hydroxy groups but I´m not sure on that, I´ve never seen this protecting group