The Vespiary

The Hive => Chemistry Discourse => Topic started by: Novice on May 04, 2004, 02:17:00 PM

Title: Henry reaction question.
Post by: Novice on May 04, 2004, 02:17:00 PM

In

this (https://www.thevespiary.org/rhodium/Rhodium/chemistry/para-fluoro-4-mar.html)

(https://www.thevespiary.org/rhodium/Rhodium/chemistry/para-fluoro-4-mar.html) synthesis, Bandil uses para-fluorobenzaldehyde and condenses it with nitroethane to get the nitroalcohol.

In my experience the nitroalcohol is hard to isolate, since it is easily dehydrated to the nitrostyrene thanks to conjugation. It is obvious that the fluorine atom affects the molecule in such a way that it is possible to isolate the alcohol instead of the styrene.

What I need to know is whether it is possible to react regular benzaldehyde with nitroethane and stop at the nitroalcohol. If one does not use acetic acid as solvent, and keep the entire isolation process if not basic then at least neutral (not acidic), do you think this could be done?

Thanks in advance.

Title: Should be quite possible
Post by: Bandil on May 04, 2004, 03:47:00 PM

Read

this (https://www.thevespiary.org/rhodium/Rhodium/chemistry/phenyl-2-nitropropanol.html)

(https://www.thevespiary.org/rhodium/Rhodium/chemistry/phenyl-2-nitropropanol.html) patent on forming the correct nitroalcohol.

Use the same procedure, neutralize the trialkylamine catalyst with dilute acetic acid, and extract the nitroalcohol. Carry on directly with the reduction, using either Pd/C CTH or Zn/KCOOH nitro reduction. Any benzaldehyde left in the nitroalcohol and reduced aminoalcohol, will be removed in an acid/base extraction.

I do not see enormous obstacles in this synthesis, although i do not have first hand experience (other than the fluorinated version of course)!

Regards
Bandil

Title: Bandil, did you try oxidizing that alcohol to...
Post by: ning on May 04, 2004, 04:44:00 PM

Bandil, did you try oxidizing that alcohol to make f-fluorocathinone?

Title: Nope
Post by: Bandil on May 04, 2004, 05:08:00 PM

I didn't do that. I find the different cathinone's I have tried an incredible waste of time and raw material... I think there are better ways to treat that molecule than to oxidize it  ;)

Title: Suboptimal reaction conditions?
Post by: Megatherium on May 06, 2004, 12:59:00 AM

cfr.:

Post 505289 (https://www.thevespiary.org/talk/index.php?topic=7031.msg50528900#msg50528900)

(Megatherium: "Stoichiometry of  ammonium formate reductions", Chemistry Discourse)