Brief update: The second crop yielded another 24,81g thus the total yield is at 335,57g or 85,94% on a m/m base. Bad? I am very pleased with the results.
@tucoXxX: Taking the additional yield into account you will need 1000*500/335,57 equals to 1490g from the bromo ketone.
@w2x3f5: I respect your opinion but i disagree. The temperature cannot be too high as other routes with different solvents use higher temperatures. The RM didnt boil, i would call it a gentle reflux.
Also i doubt the duration of 2,5h is too long as there were still traces of unreacted bromoketone in the RM. And the color of the crude product appears darker than it is in fact.
A few words to the chaser of ultrapure 4-MMC. The paradox, that ultra pure substances have less desirable effects than others with some impurities is well known. This is especially true for 4-methyl methcathinone aka Mephedrone. I know what I am talking about, as I synthesized the substance via the route the official LE units all over the world are using as a testing standard (at least they did it a couple of years ago). The route uses MeHCl and Triethylamine and after the reaction an a/b extraction was conducted and then the substance was precipitated from a butanol solution with ether and recrystallized from THF. The result was an over 99% pure product, and now guess what how it worked out in terms of bioassays? Bingo! Inferior and very weak.....
The attached pic shows the now twice washed product. I assume the effect it can produce is already lower than from the first one.
Take care folks!