Verbesserte Synthese von 4MMC

[WalterFan]

may I ask how you prepare your 40% methylanime freebase sol. ? You called it freebase, which I understand is you’ve prepared yourself, would you mind to share it ?

 

[HerrHaber]

In most cases, 40% aqueous solution of the freebase amine gas is used if applicable such as the relevance of the presence of water, case in which if there is the need of freebase it can be bought anhydrous 30% in dry MeOH which I never tried for this but I bet it could work though in this particular case presence of water is needed to a certain extent in order to form the methylamine hydrobromide and hold to it so that it can be removed in workup.

 

[Dr. MMX]

How are you sure thats 4mmc tahts 85% by grams of 2b4m?

 

[HerrHaber]

calcuilating the percentage yield was done on the basis of comparing the moles of isolated product with the amount of moles that could have been only theoretically obtained

 

[HerrHaber]

I apologise for not having any instrumental analytical data for our products which in our case it should be clear that is crude product of the synthesis unrecrystallised maybe just washed. I can try to make use of my long lost glassblowing knowledge and pull some capillaries to get some melting points if you want me to. Seeing your products looked quite delicious it would be even more so with some XRD spectra and of course an LC-MS compared with standard would be excellent.

 

[Dr. MMX]

It is not very common to receive very pure product in the powder, it can vary on the final yield and purity a lot. I have received 234 grams of powder, it didnt require a lot of washing but I am sure its not pure becasue I wasnt precise enough. From my experience it should be clear white - then it leads to more than 90% of powder yield 98+% crystals that dont need futher washing, and almost all of the solvent used for cyrstalisation is used, instead of "worse batch" beeing left). . Do not have a way right now to perform proper tests as you suggested.
I just wonder if its that good yield on more precise measurement than powder that we dont know unless its tested.
See the example of 234 grams yield - it was white but I am sure it wont lead to 210 grams of final 98%+ crystals

 

[Dr. MMX]

I do have 234 grams in DCM

300g 2b4m 900ml dcm
460 ml methylamine
nahco3 5% 500 h2o
1500 h2o

1100 acetone for acidification
200 acetone for purification

i did synethsis on roundbottom flask. basicly the methylamine on that batch can be probably be poured all at once, but with good "road" a thin layer on the wall.


I was recording a video of this job but it was just standard procedure, nothing abnormal
I mean i need to distill acetone for acidification otherwise it leads to discolors.
after filtratoin it was a little yellow solution.
pic 1 before fitlration
pic 2 the color of wastes - perfect for distilation of acetone
pic 3 color of solid after sucking out liquid

 

[Dr. MMX]

if need some more photos please ask i got 3 hours material

 

[dnBQByvHb8Zkawbjpx]

What was the temperature, time and stirring for the amination reaction? DCM is quite tricky as far as I can tell.

 

[Dr. MMX]

i poured 33% (methylamine in total) of each part every 10mins, afer 30rd min it was 30 degrees
starting temp was about 24 i think
after it was heat to 38 i put 2h, but i noticed later that it dropped to 36 37 were fluctuations so i dedcided to add one hour more.
I believe it was very sghort boling time like 2mins, so it wasnt the best but its all becasue of greed when i ve seen 36 stirring for already 1h....

 

[Dr. MMX]

I will add it all at once the next time but ofc using drip funnel

 

[Dr. MMX]

temperature inside rm after 2nd bastch of methylamine with 10 min waiting, but i am sure that termometer lowered its 2-4 degrees during that 5 s of taking it out
the water bath was at 27.4 temp at this time
cobndenser did its job as well, i am pretty sure ice water bath for its liquid was the top choice.
basicly its possible to perform about 80% of flasks volume syntehsis but ofc its not advised.

 

[TheVacuumGuy]

i usually use a plastic box (like the curver's) , i put it on the hotplate, and the flask goes in the box. As soon as i notice it might start boiling, ill throw in a layer of water.

but the plate's display is broken, and the other day the thing was way too hot, so i threw in a few liters of water and it went straight through, over the hotplate, over the floor , over electric wiring. So make sure it is not >100c

 

[Dr. MMX]

I have 2 beakers, both in boling solvent, then I add powder. in the end of adding powder usually its calculated to add some boiling solvent, and in th epreceise mooment of add ing all its moved into 100c oven inside hot water bath

 

[BuryVatorynov]

How much gram mmx u get form this synthesis??

 

[abis777]

How much Dmso to do synthesis for 20g bromeketone?

 

[BuryVatorynov]

ethyl acetate and dmso now work this way no reaction occurs at all, it does not heat up, the solution is colorless

 

[abis777]

I want to do dmso and dcm. That doesn t work?

 

[abis777]

NMP is restricted in UE, can t get my hands on it

 

[Dr. MMX]

it does and has good combo

 

[Dr. MMX]

but i dont know why use dmso at all.

 

[HerrHaber]

I found myself around getting hold of it and that wasn't hard to do here... I ordered my first bottle through an official supplier I have an arrangement with nonetheless.

 

[abis777]

to replace nmp with dsmo like in the synthesis. Or NMP is not necessary?

 

[HerrHaber]

Well this procedure had a phase when only substrate, amine and DCM were employed in the reaction along with strong stirring and quite many hours of patience even overnights yet results were incomparable in both difficulty and yield as well as quality and presumed purity.

 

[HerrHaber]

Both DMSO and DMF are suitable in an NMP sense but retting rid of them without losing product is to experimented with and not assumed it works as NMP does... however I once had no NMP left and added half the volume of NMP I would minimally needed of GVL (gamma valerolactone), about 5mL, and it worked out very good by the same method, though some residual scent of GVL had me washing it again after drying the product.