Author Topic: Halosafrole purification  (Read 1067 times)

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Vibrating_Lights

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Halosafrole purification
« on: October 28, 2001, 07:00:00 AM »
Swim wanted me to ask what is the best way to purify a halosafrole compound without distillation.  Will basic solutions do any damage to the molocule.

foxy2

  • Guest
Re: Halosafrole purification
« Reply #1 on: October 28, 2001, 11:43:00 AM »
The following is just my gut feeling, I don't know for sure.

I would imagine that it is highly dependant on which halo you are talking about and what solvent that the halosaf is dissolved in.  Weak to moderately basic solutions are probably fine.  I would stay under pH 11 to be safe.

I imagine chloro is most resistant to base and the resistance decreaseing as you go to bromo and even less as Iodo. 
Exactly how resistant?
Who knows.

Try this article.
Olefin proportions from E2 reactions of secondary alkyl bromides.  Mechanistic implications.
 J. Am. Chem. Soc.  (1975),  97(9),  2477-81.
 
Abstract
The olefin proportions from E2 reactions of 2-butyl, 2-pentyl, 3-pentyl, 4-methyl-2-pentyl, and 2-methyl-3-pentyl bromide with Bu4N+ Br- in acetone, Et4N+ F- in acetone and DMF, KOCMe3 in DMF and Me3COH, and KOEt in EtOH were detd.  The departing Br hinders the free rotation of the alkyl group on Ca; the transition states of E2 reactions promoted by strong bases have better developed double bonds than those promoted by weak bases; and the strength of the base is more important than the size of the base in controlling positional orientation.  The solvent type (i.e., protic or aprotic) may be more important than has been generally recognized. 

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