2C-B Syntheses Experimentation

Experiment #1 2C-B Syntheses

2,5-dimethoxynitrostyrene:

30g 2,5-dimethoxybenzaldehyde and 3g anhydrous NH4OAc was dissolved in 60ml of nitromethane. The solution was permitted to simmer gradually for 4 hours and the solvent was distilled off under vacuum. The black residue was poured into 150 ml IPA, and crystallized into a crystalline mass of orange needles. The crystals had been filtered with suction and dried on filter paper.

I didn’t enjoy the colour of the crystals (too much of a dirty orange), so everything was thrown into 100 ml of new IPA, stirred, and filtered and dried, and now the colour had improved enormously. Both IPA solutions was evaporated in vacuum to give ~30ml of a black, tarry substance with an acetous smell. Freezing or trituration of the pitch did not give any results, so the pitch has been thrown out of the window (look out!)

The return of dry, orange crystals of 2,5-dimethoxynitrostyrene has been 22.2 grams (58 percent )

2C-H freebase:

20 grams of LAH was inserted to 200ml THF in a 1000ml two-necked RB flask, equipped with a magnetic stirrer, and it fizzed some, but not much.

Currently 20 g of the aforementioned nitrostyrene was added dropwise as a solution in 200ml THF through a dropping funnel, which caused the method to boil, and when all had been added, the solution was allowed to reflux for 24 hours. The reaction mixture was allowed to cool, and 15ml IPA, followed by 15ml 15% NaOH solution, 30 ml THF, and eventually 50ml of chilly water, as fast as the exothermic reaction allowed. The solution now became a white sludge, which was filtered through a pad of celite, and the filter cake washed with some added THF.

The solvent was removed under vacuum, and the residue dissolved in dilute H2SO4, and washed with 3x25ml CH2Cl2, made basic with 25% NaOH solution, and expressed with 3×30 ml CH2Cl2. The extracts had been dried over MgSO4, filtered, and the solvent removed under vacuum. The residue was dried in 3 mmHg to give 10 grams (57 percent ) of a slightly yellow oil, 2C-H.

2C-B Hydrochloride:

The amine was dissolved in 15 ml glacial acetic acid, and 10 g of bromine at 20 ml glacial acetic acid was added (that the bromine flask was cooled in the refrigerator for approximately 20 minutes before opening, and so virtually no bromine vapors escaped to the space.

If the bromine is cooled for a longer time than that, it solidifies). Shortly the solution became a brownish crystalline mass, which had been permitted to cool in the fridge, and was subsequently filtered and washed using 2x20ml cold acetic acid, which enhanced the color of the crystalline 2C-B hydrobromide to a color of gray, instead of a dirty bromine-brown.

Attempts to recover more 2C-B from the mother liquor and the washes failed due to heavy emulsions. The 2C-B HBr was dissolved in 100 ml of warm water, and basified with 25% NaOH solution. This was extracted with 3x30ml CH2Cl2, the pooled extracts dried over MgSO4, filtered, and the solvent removed under vacuum. The light amber residue was dissolved in a solution of 2.5 ml glacial acetic acid in 15ml water with stirring, followed by the addition of 6.5 ml of 37% HCl.

In a few minutes, the remedy solidified to some tan crystalline mass, which has been filtered with suction, washed with 50 ml water and 75ml ether, then sucked as dry as you can. Efforts to regain more 2C-B in the filtrate and washes through acid/base extractions were fruitless. The precipitate was first air dried on a filter paper, then in a vacuum desiccator. The resulting white crystals of 2C-B hydrochloride weighed against 9.0g (63 percent ).

Overall return from 2,5-dimethoxybenzaldehyde 20 percent (Shulgin’s return 23%)

Leave a Reply

Your email address will not be published. Required fields are marked *