4-MMC (mephedrone) synthesis. Bromination in dichlormethane.
- Thread starter Marvin "Popcorn" Sutton
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On other forums where 4mmc synthesis is discussed, it is believed that acid-base extraction contributes to the appearance of iso-4mmc and pirazins, I would like to know your opinion regarding this statement. If all the same make a full-fledged acid-base extraction, how many KOH do 1kg 4mms need? Or navigate the level of pH? To what value to alkali the solution?
do not do that!!! acid-green extraction is not for 4-mmc. The 4-mmc free base is too brittle for this and easily decomposes during this procedure. just boil the water. hydrochloric acid (HCl) is a gas. the solvent (water) will leave - HCl will also leave. the 4-mmc resulting from the evaporation of water will need to be crushed and rinsed with acetone. but be careful!!! when there is little water left, reduce the temperature to 50C. since 4-mmc decomposes outside the solvent at temperatures >55°C.
By the way, a useful fact. It is believed that 4-mmc decomposes at >55°C. but it is not so. when heated, 4-mmc decomposes from contact with oxygen and carbon dioxide. however, in an argon environment or nitrogen, 4-mmc does not decompose even at 300C, and a 4-mmc melt can be obtained. by the way, molten 4-mmc turns into a glassy homogeneous crystal like methamfetamine in the TV series Breaking Bad. I have personally tried it. but at home it is very difficult to provide an argon atmosphere
So I was also afraid to conduct acid-base extraction. I have always done so, but this is a difficult task of more than 1 kg. I want to try to drive away the water to a concentration of 1 kg 4mmс per 1000 - 800 ml of water, add the reprimand (acetone or isopropanol) and send it to the freezer to precipitate the product. Before that, I would like to clean the solution well so as not to carry out repeated transistallization.
You can try steam distillation of resulting base. not for the whole volume if you don't want to. unreacted bromoketone will condense and you ll see green color on condenser. Leftover methlamine as well. Stop whenever you feel like you cleaned product enough. Wash with some NaHCO3 or Na2S2O3 10% solution, put in freezer to freeze any remaining water, decant the cleaned liquid add MgSO4, filter. Make salt
this is the best option! this is how I usually pull out the remaining 4-mmc from the mother liquor after crystallization. solution is very dirty. I evaporate it at a boiling point (~ 100C), when a film appears on the surface of the solution, I remove it from heating. I cool it to ~ 50C and fill it with a double volume of acetone. mix well and put in the freezer for 10-15 hours. then I filter and get a very clean 4-mmc.
I thought to try the NMP as a solvent, judging by the video that are posted on this forum, the free base is cleaner than on dichlormethane, on other forums they wrote that Orto Xilole is obtained a cleaner base. Have you encountered NMP? I can’t find information about the correction of the temperature regime, it seems like it is necessary to keep 60 degrees, the video does not show that the mixture is cooling, but it can heat up much higher than 60 degrees.
Synthesis in DCM gives a very pure product if not brought to a boil (boiling DCM with water leads to hydrolysis and contamination). With NMP, everything is simple, temperature control is not needed. after the addition of methylamine, the temperature rises, reaches a plateau, and then the temperature drops. if the temperature began to decrease, then the reaction is complete. everything is simple. it usually takes about 15-20 minutes. but then you need to extract the free base from the NMP. for this I recommend using toluene or orthoxylene. for every 1kg of 4-bm, take 2.5 liters of toluene and pour 3 liters of water, stir well and the layers will separate. pick up the top layer and work with it. discard the bottom layer
What is the point of doing in Dichlormetan then? Stability of the resulting product? The boiling temperature again depends on the concentration, in a saturated solution, a certain section of time will be difficult to catch the condition on the verge of the beginning of a boil. Honestly, this is the first time I hear about the hydrolysis of dichlormethan when boiling with water. Since the NMP is so simple, why complicate the process?) In a gasoline or ortho xille, it is easier to keep the desired temperature, in time in the dichlormethan for 4 hours, that in the gasoline, in some cases, even faster in the benzene.
the boiling point of DCM is 38.8C. you need to keep the temperature no higher than 36C, then the product will be very very clean. I could not achieve such purity in toluene, orthoxylene, benzene. I don't feel comfortable working with NMP because I don't have access to 4-bm. i make 4-bm from 4-methylpropiophenone. I use DXM as the solvent in this procedure (bromination in DXM is very convenient). but if I had 4-bm ready, then I would use NMP
the amination reaction, like any nucleophilic substitution reaction, is exothermic (it proceeds with the release of heat). heat is released by itself, that is, nothing needs to be heated. Vacuum is also not needed. the reaction vessel must be open to avoid overpressure (a stoppered vessel may burst).
In most cases it is not necessary to heat the reaction mass. But if the reaction does not start or is weak, it is better to heat it up. This can be due to poor quality reagents or large amounts of water in the system.
Synthesis in an NMP takes place without a vacuum and the reactor isn't sealed, even in an open vessel, as long as there is no splashing of the mass.
Synthesis in an NMP takes place without a vacuum and the reactor isn't sealed, even in an open vessel, as long as there is no splashing of the mass.
Looks nice. Only ideal conditions for bromination need to be changed. The easiest way to brominate with virtually no odor is to brominate in DCM under a layer of water. Water absorbs hydrogen bromide, thus the smell and gases are practically absent in the external environment.
Thus, 50-100 liters of ketone can be brominated at a time.
Thus, 50-100 liters of ketone can be brominated at a time.