BBr3 Demethylation Questions

Shib · Sat Apr 09, 2005 10:16 am

I'll make this brief,

can the CHCl3 be substituted with CH2Cl2 in all steps?

I've noticed a considerably lower yield (~50%) in the clandestine application of the synthesis, one reason that i can think of is that the codeine being used in the reaction is not anhydrous. A quick look in the merck reveals that free-base codeine exists a monohydrated compound. This most certainly would be the form resulting from an A/B extraction of an OTC source. Could this monohydrate be deleteriously effecting yield of the procedure, given the the violent reaction of BBr3 with H2O?

What are suitable recrystallization solvents for morphine hydrate? my research shows that a mixed solvent re-xtal from MeOH/H2O would be a good bet, but is there any commonly accepted solvent mixture for this?
What about for codeine?

thanks

Shib

Star-light · Blacklight bulb

Guest · Sun Apr 10, 2005 4:20 pm

It is my assumption that all the Boron halides, provide similar results,
I have heard reports in literature, and amongst some practicing amateur chemists that have obtained results higher than 90% with the trichloride compound, not with the bromide, The results for the bromide seem to go this way,
But perhaps it is just impure starting materials.

Bbr3 is often used in the refining, and casting of metals, and also used in the manufacture of Plasma Televisions,
It can be prepared relativly easily, from raw materials,
Pumping HCL gas into a mixture of borax & graphite produces BCl3, without Co poisoning..
syn

Shib · Mon Apr 11, 2005 10:19 am

Guest · Tue Apr 12, 2005 6:23 am

How about pumping bromine into borax & graphite

http://synthetikal.com/synthforum/viewtopic.php?p=529#529

Should not that produce Bbr3?

Since Bromine is carefully prepared by a method that Indole has put forward, with a nice photo, Would not bromine if introduced into this reaction produce Boron Tribromide?

This would be a very feasible reaction for it's preparation

syn

ApprenticeCook · DILLIGAF

under what kinds of temperatures? i was under the impression the required temps made it not really that easy... such as 800-1000oC?

However as per usual i could be wrong.
-AC

Guest · Thu Apr 14, 2005 10:45 am

450C If I remember correctly, enough to make the borax start it's molten phase, although not really that hot.
Nothing a bunsen burner, and a glass sleeve full of the 50/50 weight mix Borax and carbon, then its needs condensing.

I would bot bother condensing, I would just run the very pure gas into Chloroform, and then just keep that handy,

Shib · Fri Apr 15, 2005 9:05 am

With regards to the procedure itself, any coments on the recrystallization question? Also if the diminshed yield of the procedure is because of the hydrated compound, what methods, aside form sumblimation, could be employed to dehydrate the compound? some literature cites heating to 80C, but would likely lead to decomposition outside of an inert atmosphere. What about dissolving in dry ch2cl2 and adding a suitable drying agent? what common drying agent would be suitably inert for this application?

I'm merely trying to fill in the holes of these so-called 'methods'; I worry that a necessary step omitted for its obviousness, may be necessarily omitted by the oblivious. My next target is the bogus cold water extraction of 222's

More sol in cold than hot ? ... go look at the Merck!

Guest · Sat May 14, 2005 5:10 pm

To answer your question I can't help think that it might be still in solution, have you got the right ph, see if a second crystalisation will occur in the filtered material,

Maybe a little heat will dehydrate the substance, or you could turn it into a salt, then work with that,

Why not extract that basified filtrate with a little chloroform, collect the morphine, then gently warm to obtain the remainding species.

Syn

svacheme · Wed Jul 20, 2005 8:26 pm

Perhaps the addition of molecular sieve 4A, a very hygroscopic compound, would remove all water, and the sieves could be easily filtered out. Since these are somewhat difficult to obtain, it would be better to first dry to constant weight.