The Vespiary

The Hive => Methods Discourse => Topic started by: psychokitty on February 26, 2002, 01:40:00 AM

Title: Sodium dithionite for use in reducing oximes
Post by: psychokitty on February 26, 2002, 01:40:00 AM
I quote from "Encyclopedia of Reagents for Organic Synthesis" under the sodium dithionite heading:

"Oximes to Amines.  Oximes are readily reduced to amines by sodium dithionite.  Substituted phenethylamines are key intermediates required for the synthesis of isoquinoline derivatives.  They are readily obtained from aryl alkyl ketones by nitrosation of the alkyl group followed by the reduction of the resulting oxime derivatives by sodium dithionite."

The illustration they have on the page is an example of the reaction and it looks to me as if it's a phenethylamine but with the cathinone structure (has a carbonyl group at the benzyl position).

Anyway, Rhodium, you've been looking quite some time for an OTC method of reducing those products--I forget the name for them--formed from the reaction of an alkylnitrite and an acetophenone or a propiophenone in HCl-saturated solvent.  The reduction of these--depending on the ketone used--would yield g-aminoacetophenones or a-aminopropiophenones as products, I think (sorry, this cat's a little rusty). 

The cool thing is that sodium dithionite is available as a pool chemical (again, I think).  But I could be wrong.

The bad part about all this is that the reference seems to have a typo in it:

Pictet, A.; Gams, A.  CB (journal?) 1909 (Year?  It's in bold type), 42 (Volume, I guess), 2943 (page number, I think). 

That year can't be right.  It must be a typo.  Perhaps it's 1999.  Who knows?  Somebee care to look it up?

I wonder if sodium dithionite could be applied to the reduction of regular oximes?  Hmm.  Maybe.

Title: Re: Sodium dithionite for use in reducing oximes
Post by: Chromic on February 26, 2002, 04:33:00 AM
I don't think Na2S2O4 is a pool chemical. Sodium hydrosulfite is used in some commercial products, I've read a bit on the web that says it's used in Rit and Tintex as a color removing compound... if only we could find another OTC reducing agent.
Title: Re: Sodium dithionite for use in reducing oximes
Post by: Antoncho on February 26, 2002, 08:27:00 AM
Am i mistaken that there's an article on Rh's that describes oximes being cleaved w/dithionite to the parent ketones/ald's? (Edit - yep, it's here:

https://www.thevespiary.org/rhodium/Rhodium/chemistry/redamin.dithionite.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/redamin.dithionite.html)

) Funny! Funny!

Antoncho

P.S. Dithionites are made by reducing alcoholic bisulfite soln's w/Zn powder, AFAIK, but i'd dearly like to see an experimental proc. of their prep'n someday.
Title: Re: Sodium dithionite for use in reducing oximes
Post by: Rhodium on February 26, 2002, 11:56:00 AM
The ref you are looking for is Pictet and Gams, Berichte 42, 2943 (1909) - but according to

http://www.undcp.org/bulletin/bulletin_1952-01-01_3_page006.html (http://www.undcp.org/bulletin/bulletin_1952-01-01_3_page006.html)

they used SnCl2 to reduce the oximinoketone to an aminoketone - perhaps there are multiple preps in the journal?

This ref on my page that Antoncho mentions says dithionite cleaves oximes, and reduces imines - strange. Bull.Soc.Chim.Fr. 4, 565-577 (1986) talks about dithionite reductions of oximes though.
Title: Re: Sodium dithionite for use in reducing oximes
Post by: Dr_Sister on February 26, 2002, 07:55:00 PM
bees would be hard pressed to find a less expensive reagent, if this works it could be a huge breakthrough, nomo messy Al/Hg anymo
7.10.01
Title: Re: Sodium dithionite for use in reducing oximes
Post by: psychokitty on February 27, 2002, 12:13:00 AM
I could swear that sodium dithionite is part of some toilet-cleaning compositions for removing iron or something (along with sodium sulfite, I think).  Some of the major chain stores carry the product I'm talking about. "Iron Out" is the name, again I think.

BTW, the same encyclopedia reference I gave above also mentions the cleavage of oximes to ketones.  Perhaps the reaction conditions are similar but different enough to yield different products.
Title: Re: Sodium dithionite for use in reducing oximes
Post by: PolytheneSam on February 27, 2002, 02:46:00 AM
I saw some kind of OTC rust remover with it in before.
http://www.geocities.com/dritte123/PSPF.html