One-pot Amphetamine Synthesis From P2NP With NaBH4/CuCl2 (1kg scale)

[GhostChemist]

Reaction scheme:

​

Equipment and glassware:

• 50 L batch reactor with a reflux condenser, top stirrer and heating apparatus in a set-up;
• Drip funnel;
• Conventional funnel;
• Laboratory grade thermometer (up to 150 °С);
• Several buckets for 10 and 20 L;
• Measuring cylinder for 1 L;
• Vacuum source;
• Laboratory scale (1-2000 g is suitable);
• Cold water bath sours for reflux condenser;
• Nutsche filter;
• pH Indicator papers;
• 5 L x2 Beakers;
• Freezer;
• Pyrex dishes for crystallization;

Reagents:

• Isopropyl alcohol (IPA) 20 L;
• Distilled water 6.2 L;
• Sodium borohydride (NaBH4) 1739 g;
• P2NP (Phenyl-2-propanone) 1000 g;
• Copper (II) chloride (CuCl2) 105 g;
• Sodium hydroxide (NaOH) water solution 25% 8 L;
• Dry acetone 2.5 L;
• Sulfuric acid (or orthophosphoric acid);

Amphetamine synthesis

• Novator
• Apr 4, 2023
• 55

Amphetamine synthesis via NaBH4 reductive amination from P2NP...

Synthesis:

1. A mixture of IPA and H2O 2:1 (18 liters) is added to a 50 L batch reactor.
2. Solid NaBH4 (1739 g) is added in one portion and stirrer is turned on.
3. Pure P2NP (1000 g) is added in several small portions to keep the mixture temperature below 60 °С.​

P2NP (Phenyl-2-propanone)
​

4. A solution of CuCl2 (105 g) in water (200 ml) is slowly added dropwise to keep the mixture temperature below 80 °С.​

CuCl2 and CuCl2*2H2O​

5. Thereafter, reaction is kept at 80 °C for 30 minutes with help of external heating.
6. A NaOH (8 liters 25%) water solution of is added to the reaction mixture and layers are separated.
7. The aqueous phase is extracted with 8 liters of IPA. Amphetamine free base is dissolved in IPA and IPA layer density is changed, hence, it is separated from aqueous layer.
8. The IPA from step 7 extract is evaporated on vacuum to an amphetamine free base oil and combined with free base from step 6.
9. The amphetamine free base oil is dissolved in 2 L of dry acetone.
10. Sulfuric acid (or orthophosphoric acid) is added dropwise to reach pH 6 (with a constant stirring).
11. Then, the mixture is put into a freezer for 12 hours.
12. After crystallization procedure in the freezer, the suspension of amphetamine salt is filtered with help of nutsche filter and washed with a dry cold acetone to white color. Acetone from washing procedure can be crystallized as described at steps 11-12 (amphetamine salt quality from this solution will be lower).
The reaction yield is 60-70 %.​

 

[Sasha89]

First off all thank you very much for these very interessting synthesis route.
Is a 30l glass reactor useable for this way? (Something like that u see on the picture)
And how do you realize the stirring? Are you using a electrical overhead stirrer?

 

[WillD]

yes
need over-head stirrer for this flask type

 

[rickyrick]

If scaling this reaction up do you scale everything or extracting the aqueous layer with IPA doesnt need to be linear scaled?

 

[MadHatter]

This is a really nice synthesis without the mercury waste or possible mercury contamination generated by the Al/Hg reduction. I saw it on The Vespiary some months ago and was going to do a write-up here once I'd tried it myself. But as usual, you guys beat me to it . Thanks for the excellent text!

 

[diogenes]

Is it possible to scale this down? I have all the ingredients, but would rather try on a small scale first.

 

[Uncle Lee]

This reaction is very good on a small scale
In a large reaction, trying to control the exotherm and the large amount of foam by putting the CuCl2 solution slowly into the flask will not give a high yield, there may be nothing but nitroalkanes and the concentration of nanoparticles will be too small to reduce the nitro, the largest flask possible should be used and the entire CuCl2 solution should be added at once

 

[RickyKasso]

What do you consider as "small scale"? Is there any specific amount of P2NP and respective amounts of the other chemicals to have the most optimal and easy going reaction?

 

[UWe9o12jkied91d]

30g

 

[btcboss2022]

Hello,

Is normal to have a solid precipitate after point 6? I made twice with the same result I just filtered.
Thanks.

 

[WillD]

Yes, an insoluble precipitate should fall out. So, we remove excess salts, getting the base.

 

[syntheticdrugs]

William DampierHello, can I use something else instead of sodium borohydride in this reaction?​

 

[G.Patton]

Hello, yes. Al/Hg, LAH, Pd/C and H2, Ni/Re and H2. Last two are quite not recommended for a novice.

 

[Sasha89]

What is the best way to carry out an extraction with such big quantities, stir well and then decant?
and does the distillation have to be carried out in a vacuum or can the IPA also be distilled off in the normal way?

Sorry for the last writing in german, didnt see that autotranslator was on

 

[WillD]

The alcohol (or other extraction solvent) must be evaporated, otherwise crystallization of the final product will be a problem.

 

[Sasha89]

possible to do the vacuum distillation with a pump with the following specs:
Flow rate (max.): 5.5 l/min.
Ultimate vacuum (max.): 160 mbar (abs.)

and what would be the boiling point of the IPA with ussage of this pump

 

[Montecristo]

Any major risks with this synth?

 

[WillD]

The reaction with sodium borohydride may get out of control if you do not monitor the temperature. In addition, small-dispersed copper compounds can interfere with the purification of the final product.

 

[V€ctor Company]

If
the reaction of the sodium borohydride does go out of control, what can I do about it, is the synthesis botched? If there are small dispersed copper compounds, is it impossible for me to remove them when purifying?

 

[InLikeFlynn]

I had p2np flare up after an unintentional quick addition with the nabh4 it didn’t do anything negative to my final product.

I filter all the copper compounds out with 2-3 coffee filters after letting it sit after the 80c heating.

 

[Montecristo]

Thanks !

 

[Mclssmxxl]

In small scale can the workup be replaced with salting out the ipa after alkalization and extracting with say toluene then dried over something appropriate? I dont see why not but maybe im missing something.I dont own a rotovap.

 

[Sasha89]

What do you use for external heating to keep the temperature on 80 °c for 30 mins?

 

[GDC]

Metal dog food feeding dish with water.

 

[Mclssmxxl]

Hotplate, heating mantle(might be too much even on low), deffo not open flame.

 

[G.Patton]

Worth using Batch chemical reactor for this scale.

 

[Sasha89]

After dozens of successful syntheses, it actually failed for me this time.
my glass reactor had a small crack which unfortunately led to a large one and has therefore become leaky. Luckily this happened shortly before the addition of CuCl2. I then stopped the synthesis, quenched the reaction with H2o and put it in a canister.
My question now: Can the mixture of NabH4 and P2NP be separated in any way so that both can be returned to their original forms? so that it can be used again for another new synthesis.