[paul cotter (OP)]

I gather from previous posts you are involved in regulatory matters. My question relates to methyl fluorosulphonate aka "magic methyl".I was of the opinion that it's use was effectively banned due to it's hazards. Now supposing a researcher needed a methylating reagent with above average leaving group would the use of "magic methyl" be sanctioned? Also diazomethane is used if needed and I would imagine it to be equally hazardous to one's dna. I appreciate that diazomethane has quite unique properties that could not be substituted for by an alternative.

[chiralSPO]

I'm not Bored chemist, but as a chemist, would be happy to offer some insight.

I would imagine it to be equally hazardous to one's dna.

Any methylating agent with a sufficiently good leaving group will be able of damaging DNA, unless it is so good it reacts with water first or is not bioavailable (polymer supported methylating agents would be much harder to get into cell nuclei).
https://pubs.acs.org/doi/pdf/10.1021/ol025633s
http://www.arkat-usa.org/get-file/29478/

diazomethane

diazomethane is only useful as a methylating agent under acidic enough conditions to protonate the methyl group (for example, methylating carboxylic acids).

What are you hoping to methylate?

[paul cotter (OP)]

No, I am not planning on methylating anything, I am a retired electrical engineer with an interest in chemistry(and all areas of science). I had heard that methyl fluorosulphonate was effectively banned from lab use and I was wondering would that apply in say, a research lab. The reason I referred  to diazomethane was in addition to carboxylic acid and phenol methylation I have seen it used for some carbene insertion reaction for which I know of no possible substitute whereas dimethyl sulphate could in theory substitute for methyl fluorosulphonate. When I was in the undergraduate chemistry lab there were no warnings about dimethyl sulphate at all!-I am sure I would have splashed it around carelessly as there multiple bottles around the lab and it was given as much respect as if it were water by everyone-and i'm still alive 52 years later. I wouldn't go near any of these things now.

[chiralSPO]

Thanks for the clarification.

Yes, diazomethane has a very rich chemistry, beyond mere methylations. It is extraordinarily hazardous too: in addition to its substantial toxicity, it is prone to detonation if it gets too hot, or if it is treated roughly. There is a silylated version which is slightly easier to handle (trimethylsilyl diazomethane), being a liquid rather than a gas, but even then... yikes!

One of my colleagues in grad school referred to diazomethane as "Angry Yellow" because of its apparently ill temper and its bright yellow color.

[paul cotter (OP)]

Yep, diazomethane is a nasty one, no ground glass fittings and a blast shield needed. Although I did three years chem/biochem I don't think I was suited to lab work. One day due to boredom with the prescribed work I decided to have some fun. I prepared ~10grams of manganese(7) heptoxide in a heavy duty boiling tube and from a distance flicked fragments of impure acetanilide(which we were supposed to be purifying by recrystallization). Eventually I got a few fragments in-flash boom and pandemonium ensued. The tube did not shatter and the contents hit the ceiling in a beautiful symmetric black circle. The report was very loud and it brought most of the department running. I got in a shitload of trouble over that and I had to write an accident report . No point being in the lab if you can't have some fun!    I suppose I just have a mischievous personality.

[Bored chemist]

To the best of my understanding, no chemical is banned in the UK, EU or USA.

Some are restricted for various reasons- eg as drugs or drug precursors, chemical weapons, and a few others.
Some are effectively banned from bulk use (outside of laboratories):  nitrobiphenyl, benzidine, aminobiphenly and beta naphthylamine.


On the other hand, there is legislation that requires you to assess the risks from your work and, as far as you can, to minimise them.
If you can write a risk assessment that explains why you need to use the stuff, then you can use it.
You would need to show (1) that the job needs to be done and (2) there's no safer way to do it.