- Language
- 🇬🇧
- Joined
- Jan 1, 2023
- Messages
- 64
- Reaction score
- 76
- Points
- 18
Reagents:
1. 134 g P2P are slowly dissolved in 1000ml absolute THF
2. 46,58 g MeNH2 solution in 1000ml absolute THF is added over a 30 min period. (This solution prepared is by dropwise addition of 116 ml 40% aqueous solution of methylamine onto dry NaOH pellets (app. 250g) using a dropping funnel with constant pressure. The evolving MeNH2 gas is bubbled into cold THF placed on an ice bath.)
- 134 gram 1-phenyl 2-propanone P2P (1 mol, 1.0 equiv)
- 46,58gram Methylamine (1.5 mol, 1.5 equiv) in 1000ml Tetrahydrofuran (THF)
- 120 gram Glacial acetic acid GAA (2 mol, 2.0 equiv)
- 318 gram Sodium Triacetoxyborohydride NaBH (AcO)3 (STAB ) (1.5 mol. 1.5 equiv)
- Tetrahydrofuran (THF) 2000ml
- 2 N NaOH solution appr. 2000ml
- Ethyl acetate EtAc
- Magnesium Sulfate MgSO4
- Brine
Procedure1. 134 g P2P are slowly dissolved in 1000ml absolute THF
2. 46,58 g MeNH2 solution in 1000ml absolute THF is added over a 30 min period. (This solution prepared is by dropwise addition of 116 ml 40% aqueous solution of methylamine onto dry NaOH pellets (app. 250g) using a dropping funnel with constant pressure. The evolving MeNH2 gas is bubbled into cold THF placed on an ice bath.)
3. 120 g Glacial acetic acid is added slowly.
4. 318 g Sodium Triacetoxyborohydride is added in small portions of 10-15g.
5. RM is warming to appr. 40-50°C and foams a bit.
6. The pale whitish, light viscous RM is vigorously stirred (overhead) for 2 hours.
7. Solvent is removed by rotovap under reduced pressure.
8. Residue is carefully basified to pH 12 with 2 N NaOH solution.
9. Metamphetamine freebase is extracted with 2x300ml Ethyl acetate, the organic layer is washed twice with brine (appr. 50Ml each), dried over anhydrous MgSO4 and concentrated under reduced pressure.
Yield: 138 g pale brownisch/yellow Methamphetamine oil (92,6%)
Remarks:
Downside to this reaction is the high price of STAB. The good news, its quite easy to prepare from NaBH4, THF (or Toluene) and Glacial acetic acid in slight stoechiometric excess.
4. 318 g Sodium Triacetoxyborohydride is added in small portions of 10-15g.
5. RM is warming to appr. 40-50°C and foams a bit.
6. The pale whitish, light viscous RM is vigorously stirred (overhead) for 2 hours.
7. Solvent is removed by rotovap under reduced pressure.
8. Residue is carefully basified to pH 12 with 2 N NaOH solution.
9. Metamphetamine freebase is extracted with 2x300ml Ethyl acetate, the organic layer is washed twice with brine (appr. 50Ml each), dried over anhydrous MgSO4 and concentrated under reduced pressure.
Yield: 138 g pale brownisch/yellow Methamphetamine oil (92,6%)
Remarks:
Downside to this reaction is the high price of STAB. The good news, its quite easy to prepare from NaBH4, THF (or Toluene) and Glacial acetic acid in slight stoechiometric excess.