Antoncho (Official Hive Translator)
01-10-02 17:12
No 254789
      Dioxane dibromide  Bookmark   

This appears to bee a versatile reagent used for bromination in organic chemistry - at least in the literature i've read. It is also very easily prepared as well as cheap (dioxane, i mean).

I am wondering if anyone knows if this compound would bee a better brominating agent for 2,5-diMeOstuff - in terms of yield, as it always sucks w/Br2 straight.

Also - could one substitute it for N-bromosuccinimide in rxns like alkene-->bromohydrin?

If it occurs of any use, i'll post the procedure of its prep'n.

Antoncho
 
 
 
 
    foxy2
(Distinctive Doe)
01-10-02 18:03
No 254804
      Re: Dioxane dibromide  Bookmark   

Antoncho
I have some other interesting refs about Dioxane dibromide that I will run up to the library and get.
Foxy

Studies on bromination of phenol by dioxane-dibromide.
Li, Yingfu; Wang, Hongjun.     
Huaxue Shiji  (1992),  14(1),  50-1.
Journal  written in Chinese.

Abstract
The title reaction was studied under a variety of conditions, i.e., different reaction temps., vols. of ether solvent, or addn. sequences.  p-Bromophenol was the major product, in <=91.4% yield.

I hate my government, does this mean I'm a terrorist??
 
 
 
 
    halfapint
(Ubiquitous Precursor Medal Winner)
01-10-02 18:56
No 254829
      Re: Dioxane dibromide  Bookmark   

Aw, come on Foxy, just tell us in Chinese. You don't have to translate.

Antoncho, could bee that folks here might want to know how to make dioxane dibromide just out of abstract academic interest. Who cares if it's useful or not, right? Anyway, might give me a clue whether boron trifluoride (or diborane) complexes with dioxane, as with THF. Each of these data would bee valuable additions to our disinterested quest for pure knowledge. I made lots of dioxane, and like you said it's real easy.

The Hive is an institution of higher learning. We're all here to learn how to get higher.

Sans Marx, sans Jes¨s --- Daniel Cohn-Bendit
 
 
 
 
    PrimoPyro
(Hive Prodigy)
01-10-02 21:21
No 254884
      Re: Dioxane dibromide  Bookmark   

Antoncho: Have you read the entries in TS2 regarding dibromodioxane? If not, I can copy them here.

foxy2: Please post that ref as soon as you can! Brominations are especially interesting to me lately!

halfapint: What was your method for producing the compound? Same as TS2? Ethylene glycol ==H2SO4==> Dioxane? Yields? Scale per reaction? Thanx.

                                                 PrimoPyro

Vivent Longtemps la Ruche!
 
 
 
 
    foxy2
(Distinctive Doe)
01-11-02 02:49
No 254980
      Re: Dioxane dibromide  Bookmark   

Pyro
Post the TS2 stuff.

I hate my government, does this mean I'm a terrorist??
 
 
 
 
    halfapint
(Ubiquitous Precursor Medal Winner)
01-11-02 12:54
No 255195
      Re: Dioxane dibromide  Bookmark   

PrimoP, whenever I put 30% (battery) sulfuric acid into say 3 volumes antifreeze and then boiled, I've so far got wet dioxane condensed. Haven't found a way to screw it up yet. Never calculated yields, because I never tried to boil it down past ~3/4 of the solution; after cooling I tossed it. We don't have to bee tight-assed about technique for something like this, do we? I was using this crude wet dioxane with (muriatic) HCl, to oxidize lignin to Hibbert ketones Post 214730 (halfapint: "The Hibbert Ketones of Lignin", Novel Discourse), a reaction in which the amount of water wasn't critical. Never dried, so never measured its concentration; I'm so ashamed.blush I'll bee better after this, promise!

turning science fact into <<science fiction>>
 
 
 
 
    Antoncho
(Official Hive Translator)
01-11-02 14:07
No 255205
      Re: Dioxane dibromide  Bookmark   


Pyro
Post the TS2 stuff.




Yes, please!

Antoncho

 
 
 
 
    PrimoPyro
(Hive Prodigy)
01-11-02 14:11
No 255206
      Re: Dioxane dibromide  Bookmark   

halfapint: LMFAO! laugh I fogive you this time, but next time it just may take a care package of some MD-P2P and maybe a little NaCNBH3 wink so bee prepared to cough it up. cool

Ok, I just wanted data, that's all. What you said answered all my questions just fine: it will work with OTC materials in MonTecTM (monkey level technology tongue)

P.S. We'll go back to those ketones later. I have not forgotten about that thread at all. wink

P.P.S. I will post the TS2 stuff in a little bit, after I eat. smile

                                                  PrimoPyro

Vivent Longtemps la Ruche!
 
 
 
 
    PrimoPyro
(Hive Prodigy)
01-11-02 18:48
No 255319
      Re: Dioxane dibromide  Bookmark   

Ok, here's the full entry for the dibromodioxane, near verbatim:

METHOD #2: [128, 129]--To make dibromodioxane one stirs 500g dioxane in a flask which is in an ice bath, all of which is in the (fume) hood. 990g of liquid Br2 is rapidly added, causing the solution to get hot (one can also bubble in an approximate amount of bromine from a gas canister). The solution is dumped into a bucket containing 2L of ice water, causing the immediate formation of a large mass of orange dibromodioxane crystals which are seperated by vacuum filtration and dried."

"In an ice bath a flask containing 100g 1,3-benzodioxole or catechol or guaiacol and 200mL ether is stirred and then 200g dibromodioxane is slowly added so that the heat and reaction won't get out of control. After stirring for one hour the solution is poured into some water and the ether layer is seperated. The aqueous layer is extracted once with some more ether and the two ether fractions combined, dried with Na2SO4 and distilled to give bromo-benzeodioxole. (90%)"

References cited in the appendix:
CA, 47, 8032 (1953)
CA, 44, 8354 (1950)

Source: TSII, pg. 224 If you don't know, don't ask, because we won't tell. wink

                                                   PrimoPyro

Vivent Longtemps la Ruche!
 
 
 
 
    Antoncho
(Official Hive Translator)
01-13-02 13:27
No 255890
      Re: Dioxane dibromide  Bookmark   

Hm... Very nice - i wonder though what the yield w/straight Br2 would bee. As in - does dioxane*Br2 have any advantages over it.

And still - is there any possibility of this complex to bee used the way NBS is? Hardly probable, but who knows.

Primo, does TSII have any more notes on it?

Antoncho
 
 
 
 
    PrimoPyro
(Hive Prodigy)
01-13-02 18:11
No 255945
      Re: Dioxane dibromide  Bookmark   

Perhaps you were expecting more profound information? I'm sorry, but I think that is the only significant entry in TSII for dibromodioxane. I will look further though.

What do you mean by, "Is there any possibility of this complex to bee used the way NBS is?" Used like how? For what?

I believe that the only thing this entry shows is that dibromodioxane is efficient at brominating the aromatic ring in the para/meta position (in this case) instead of the meta/ortho. In these type scenarios, where NBS is used, I think dibromodioxane is equally applicable.

As far as NBS's ability to add to substances like allyl alcohol, forming allyl bromide and not attacking the olefin, I do not know if dibromodioxane has the same ability.

Personally, I have often wondered about creating diiododioxane (sheesh thats hard to read) for aromatic iodination.

                                                    PrimoPyro

Vivent Longtemps la Ruche!