4-Fluoroamphetamine: A full report.

[grandpa]

Well

According to Post 422844 (Bandil: "Verification of Bariums research", Methods Discourse), everything should be fine. Ratios are all in line with what Bandil wrote.

BUT:

the light-yellow solution did not crystallize ... so additional water was added ... Another 4.26 mL of nitroethane (8.46 mmol) was added, followed by 0.25 mL of n-butylamine

Meaning that for this very specific aldehyde the catalyst (methylamine) FAILED to complete the reaction...

WHY ?

[Bandil]

grandpa>

In my post

Post 422844

(Bandil: "Verification of Bariums research", Methods Discourse), 2,5-dimethoxybenzaldehyde was used as the substrate. This is highly activate compared to 4-fluorobenzaldehyde, and gives much higher yields in the condensation reactions. That is most likely the reason that methylamine failed with 4-fluorobenzaldehyde.

Generally speaking its a good idea to use a N-alkylamine (-propyl or -butyl) in a small excess of GAA (compared to the catalst) for the condensation, if you are working with the not so activated substrates.

Kind regards
Bandil