Banning non-chemists from starting threads

[realgar]

Where you get that? check your basic chemistry again:
Cyanogen bromide is hydrolyzed to release hydrogen cyanide and hypobromous acid thus:

My basic chemistry is okay. The Wikipedia article you cited is partly incorrect and self-contradictory. Cyanogen bromide reacts with nucleophiles (including water, amines and alkoxides) consistently as an equivalent of CN⁺ Br^-:
BrCN + R₃N = NC-NR₃⁺ Br^- --> NC-NR₂ + RBr ( https://en.wikipedia.org/wiki/Von_Braun_reaction )
BrCN + RO^- = ROCN + Br^- ( the reaction utilized in agarose activation )
BrCN + 2 HO^- = NCO^- + Br^- + H₂O (see the 1st ref. in my previous post)

Let's see how cyanogen bromide is prepared.

Cyanogen Bromide
Org. Synth. 1931, 11, 30
DOI: 10.15227/orgsyn.011.0030
Submitted by W. W. Hartman and E. E. Dreger.
Checked by Roger Adams and I. L. Ozanne.

NaCN(aq.) + Br₂ = BrCN + NaBr(aq.)

The reaction is performed by adding an aqueous solution of sodium cyanide to liquid bromine with some water. The product is then distilled (bp 61 °C) from the reaction mixture to leave an aqueous solution containg sodium bromide along with excess unreacted cyanide. This means actually that cyanogen bromide is sufficiently stable throughout the procedure, as it does not hydrolyse to an appreciable extent when heated to boiling, being in contact with water.

This means also that the reaction you wrote (BrCN + H₂O ---> HCN + HOBr) proceeds in the opposite direction. Hypobromous acid (as any oxidizer including even iodine - see http://www.orgsyn.org/demo.aspx?prep=CV4P0207 for a preparative procedure) will react with cyanide to give first (CN)₂ then XCN (X = Hal).

The method of BrCN deactivation with NaOH/NaOCl (wiki ref. 12) thus relies only on alkaline hydrolysis, not hypochlorite oxidation. The oxidizer is necessary only for deactivation of cyanide, and yes, both alkaline hydrolysis of cyanogen bromide and the hypochlorite oxidation of cyanide can be dangerously exothermic.

Since you referring to agarose or affinity chromatography, I gather you or your buddy are biochemists dealing in mg of the stuff safely dissolved in a solvent in a proper lab under a proper hood. Not kilo scale or in your kitchen, am I right? I was just warning about a kid I once saw trying to make the stuff from other nasty chemicals (Bromine and Cyanide!!) in his kitchen so he can make 4-MAR.

A group of chemists working for biologists, to be correct. Yes, proper lab with a good ventilation. A gram scale.

Yes, BrCN is highly toxic and shouldn't be handled outside a laboratory setting. I haven't found any direct proof of cyanide formation (e.g. by enzymatic reduction) on its ingestion, although it is widely speculated to be so. At least some symptoms of BrCN poisoning (pulmonary edema, eye and skin irritation) result from its being an electrophile rather than a source of cyanide.

 

[atara]

4-MTA was designed by professionals. It was a disaster. Mephedrone was discovered by someone with almost no understanding of pharmacology. It's just not that simple.

Hypobromous acid (as any oxidizer including even iodine

Hypobromous acid and hypobromite are too unstable to be observed (at least at normal temperatures), although mixtures containing bromide and bromate can show reactivity resembling Br+.

 

[fastandbulbous]

Fuck, justify qualifications? All my academic qualifications have been abducted by the great god fuckknows (as in,"fuckknows where they are"!). My biochem degree, my neuropharmacology masters, even my PGCE (teacher) qualification. Anybody who knows me well, will confirm I live in a state of organized chaos. I seriously doubt I could find my marriage certificate and that was only 16 months ago!

 

[paracelsius]

the product depends very strongly on pH

I didnt know bleach is able to oxidize inorganic cyanide..

Cyanogen bromide reacts with nucleophiles (including water, amines and alkoxides) consistently as an equivalent of CN+ Br-:

That is what I thought I guess instinctinvely! (BrCN being electrophilic and H2O being nucleophilic depending on pH anyway):
BrCN ---> Br+ and CN- in
H2O ---> H+ and OH-; where
Br+ and OH- ---> HOBr and
H+ and CN- ----> HCN
I didnt know the reaction proceed further (oxidation of CN by BrO to the cyanate depending on medium pH??) so yeah you right. Grateful I learn something today..Have a good'day

 

[Fertile]

I believe it was Einstein who said 'never learn something you can look up'. OK I used an old paper, but WHO remembers this stuff? If you are using the reaction then you should look it up along with the MSDS of all reagents and solvent's, but just to rote learn. No.

BTW Your work with those aminorex derivatives mean it's worth reading.

I think I mentioned we began with the aldehyde and tried a few routes but aldehyde ---> nitroalcohol ---> aminoalcohole --> aminorex (or cyclization to form piperidine and THEN to product) gives highest overall yield. I've mentioned that 3 steps is about the limit. Of course that does not allow for combinational chemistry. If 2 unusual precursors make a product, as long as you can make those 2 precursors in 2 steps each (which is 5 reactions) then you are OK. It's a very stylish method that even now is only just becoming the usual route.

Forget the NaHNCN route. Looks good but NaHNCH is unstable. Even the supplier said they could only make it in winter.

Find a direct route for ring-substituted PAC to AR in 1 step... that would be amazing.

 

[paracelsius]

That would give ring subst ARs only but not 4-substituted or combination 4-and ring-subs! unless one can get something like nitrobutane, nitropentane, hexane..etc???

There are easier general ways: --------------- 3-steps pretty much quantitative minus mechanical loss. Precursors (w/all imaginable subst) cheaper than dirt. That would give a lots of different 4-and ring subst ARs not just plain ARs.

I am really looking for 4-alkyl-ARs beyond the methyl of 4-MAR, 4,4'-DMAR..etc with or without ring subs. McNeil patent mention the ring substituted 4-propyl, 4-butyl, 4-isobutyl. These would be REALLY interesting compounds really overlooked Propably reuptake inhibitors ala cathinones/pyros like I mention in another post. But then again synth discussion is not allowed here so @MOD let me know so I can remove.

oh btw L-PAC would give only substituted 4-MARs (all with a 4-methyl)