4-MAR and CNBr question!

[Bandil]

Hi!

Swim had planned a 4-MAR session soon, and has a couple of questions about it!

1)
In the cyanogenbromide synth, they use sodiumcyanide! Swim only has coppercyanide avavible. Is it possible to use Coppercyanide instead and just callibrate for the mole weight ?

2) General comments on the cyanogen synth? Is it totally suicide to attempt it?

3) In the 4-MAR synth they use methanol. Is it possible to substitute this for ethanol?

4) Why is reduced pressure so important to remove the organic solvent? Can it not simply be boiled away?

Swim is VERY eager to start so please respond ASAP!

Thanks alot!

Regards
Bandil

[bottleneck]

Could someone tell me if you could make 4-MAR like so:

Apparatus: a flask with a ground joint attached to a claisen adapter with two dropping-funnels attached.

CuCN is added in one lump to the bottom of the flask and combined with a little methanol, enough so it can be stirred. One dropping-funnel is charged with elemental bromine in methanol, the other with phenylpropanolamine in methanol.

The solution of bromine is then added dropwise with magnetic stirring of the CuCN until no further reaction is noted.

Then, without changing any glass-connections, the PPA-solution is added dropwise until an excess has been added.

Would that work?

Could there be side-reactions from the copper-ions influencing the formation of the product?

[Osmium]

I seem to remember that this produces dicyan instead of the desired BrCN. Could be wrong though.
I'm not fat just horizontally disproportionate.

[Bandil]

ok, i see how that -could- be a problem. Swim does not have access to sodium cyanide, so it would be a nice idea to make some. Afa"S"k copper(i)chloride is insoluble. Could one dissolbe equimolar amounts of sodiumchloride in minimum amounts of water and add this to a soln. of copper(i)cyanide and filter the precipate? Then swim could evaporate the water carefully under vacuum to yeild sodiumcyanide??

Swim would really like some good advices on this procedure as he will soon be beginning the "adventure"


thanks alot!

Regards
Bandil

[Bandil]

Swim thought the cyanate route sounded somewhat "nicer". Does anyone have a link to a writeup on the cyanate production from urea and carbonate?

Thanks

[Rhodium]

Bandil: No offense meant, but anyone asking about if it is a good idea to prepare cyanogen bromide is probably not skilled enough to do it, unless they have a really good professional fume hood. Not a home-built one, and certainly not a fan/open window. Cyanogen bromide is a lethal, volatile toxin for real. Myself, I would never use such a vile compound outside a university fume-hood.

UTFSE for cyanate from urea/carbonate.

Racemic norephedrine can be isomerized by N-acylation with benzoic anhydride, and reaction with SOCl2 to form a 5-membered oxygen/nitrogen intermediate, which upon aqueous hydrolysis yields racemic norpseudoephedrine. See J. Forens. Sci 34(4), 962-79 (1989).