Reaction diagram |
Reagents
- 2-Bromo-4'-methylpropiophenone (case 1451-82-7) - 5 kg;
- N-methyl-2-pyrrolidone (NMP; case 872-50-4) or DMSO, DMF, Sulfolane - 20 L;
- Methylamine 40% aqueous solution (case 74-89-5) - 8 L;
- Benzene - 20 L;
- Acetone - 30 L;
- Hydrochloric acid in aqueous solution (HCl 36%) ~ 1.5 L;
- Distilled water - 20 L;
- Magnesium sulfate (MgSO4);
Equipment and glassware
- Batch reactor equipped with drop funnel, top stirrer, thermometer, temperature control system and reflux condenser;
- pH indicator paper;
- A balance
- Vacuum pump;
- Funnel;
- Several buckets - 25 L;
- Barrel -100 L;
- Beaker - 2000 mL;
- Test tube - 1000 mL;
- Glass rod and spatula;
- Spoons;
- Nutsche filter;
- Rotary evaporator;
Synthesis procedures
- 5kg of 2-Bromo-4'-methylpropiophenone (or other crude 2-Bromo-4'-methylpropiophenone after halogenation reactions) is poured into the batch reactor.
- Next, 20 L of N-methyl-2-pyrrolidone is poured into the reactor. Switch on the top stirrer and heat the reaction mixture to 40 °С.
- When the temperature reaches 40 °С, 8 L of methylamine 40% aqueous solution is poured into the mixture and mixed for 20 minutes.
- Afterwards, 20 L of distilled water is placed in the reaction mixture and stirred for several minutes.
- 15-20 L of benzene or other suitable solvent is poured into the reactor, and the mixture is stirred for a few minutes.
- When the stirrer stops, the mixture is divided into 2 layers.
- The lower aqueous layer is discharged through the bottom valve of the reactor. The upper layer is drained into a bucket and dried with MgSO4. This is then poured into another bucket.
- 20 L of ice-cold acetone is added to the mixture, and hydrochloric acid (HCl 36%) is added dropwise with constant stirring to achieve a pH of 5.5-6 .
- The mixture is placed in the freezer for around 12 hours.
- The crystallized mephedrone hydrochloride is then filtered and air-dried. The yield is 58%.
Source: William Dampier ( /media/mephedrone-hydrobromide-synthesis.57/ )