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Synthesis of 25B-NBOME from benzaldehydes with nitromethane

William Dampier

Well-known member
Jul 19, 2021
Reaction score
Step 1. 2,5-Dimethoxynitrostyrene.

1. 2,5-dimethoxybenzaldehyde 1000 g was dissolved in 5 liters IPA at 80 *C.
2. Nitromethane 735 g, acetic acid 200 ml and ethylene diamine (cyclohexylamine, butylamine) 37 ml were added in the stated order and the reaction were kept at 80°C with stirring for 3 h.
3. The mixture was then kept in a fridge overnight causing crystallization.
4. The solids were filtered and washed with cold IPA yielding as a crystalline yellow solid (600 g, 60%).

Step 2. 2,5-Dimethoxyphenylethylamine.

1. Sodium borohydride (480 g) was suspended in 5 liters of IPA.
2. 2,5-Dimethoxynitrostyrene (600 g) added in small portions when stirring.
3. Decomposition of the excess borohydride.
4. Extraction and distilled.
5. 500 g yellow oil (propane).
6. Add 5 liters of IPA.
7. Add 8 mmol Zn.
8. Add 3.5 mmol HOAc.
9. 240 g base yellow oil.

Step 3. Halogenation.

3.1. Bromination var.

1. 2,5-Dimethoxyphenylethylamine base added in the flask.
2. HBr 48% 1.1mmol added in the flask and stirring.
3. H2O2 1.1 mmol dropwise in the flask and stirring.
4. After added all H2O2 stirring 1,5 hours at room temperature.
5. Extraction with EtOAc and added acetone.
6. Acidify HBr 48% or HCl conc. at pH 6.
7. Put in freezer at 12 hours.
8. Filtrate and dry 4-bromo-2,5-Dimethoxyphenylethylamine hbr (hcl).

Step 4. NBOMe.

1. To a suspension of the 2C-X hydrochloride (or hydrobromide) (1.0 mmol) and 2‐methoxybenzaldehyde (1.1 mmol) in EtOH (10 mL) was added Et3N (1.0 mmol) and the reaction was stirred until formation of the imine was complete according to (30 mins to 3 hrs).
2. NaBH4 (2.0 mmol) was added to the reaction which was stirred for another 30 minutes.
3. The reaction mixture was evaporated under reduced pressure and redissolved in EtOAc/H2O (30 mL, 1:1).
4. The organic layer was isolated and the aqueous layer was extracted with EtOAc (2 × 15 mL).
5. The combined organic extracts were dried (Na2SO4), filtered and evaporated under reduced pressure.
6. The purified free base was dissolved in EtOH (2 mL) and there was added ethanolic HCl (1M, 2 mL) and the solution was diluted with Et2O until crystals formed.
7. The crystals were collected by filtration and dried under reduced pressure. Yield: 88%
Last edited by a moderator:


New member
Aug 6, 2022
Reaction score
Why would one want to ruin 2cb? Nbome was a marketing tool IMO