phenyl-nitropropene synthesis methods

[ChemicalSolution]

Is there a big difference in yields using a Dean Stark water trap and toluene as the solvent vs etOH as the sovent and no water trap?



Thanks!!!

[Rhodium]

Not in the hands of an experienced chemist, the yield depends mostly on how good the aspiring chemist is when it comes to crystallize the oil to a yellow mass. I'd say evaporate all the solvent under vacuum, and shake the remaining oil with water to dissolve any remaining catalyst, and if the nitropropene crystals does not form right away, then just put the washed organic solution in the freezer until crystals form (perhaps with scraping the sides of the beaker with a glass rod). Then recrystallize the yellow mass from a minimum amount of boiling methanol or IPA, and chill in the freezer before filtering and drying. The recrystallization greatly improves the ability to store the nitropropene without decomposition, and it also removes any water from the mix. The resulting crystals should look like frozen white whine afterwards (very light yellow).

Please get back to us with a detailed lab report when you're done.

[ChemicalSolution]

In this dream, SWIM forsees taking the toluene solution and going directly to the Fe/HCl reduction to the ketone- skipping the recrystalization step all together (as in the methoxyphenylacetone prep from Organic Synthesis).

Those folks report an over-all yield of 60-70% with this method.

Any comments?

[Rhodium]

I would imagine some excess nitroethane be reduced to ethylamine, and this in turn form an imine with the phenylacetone, which is finally reductively aminated to N-ethylamphetamine.

Of course this is just a side reaction due to the extreme pH's present in the solution, but I would think it could be an interesting thing to try to make a one-pot transformation of Piperonal to MDE, just using nitroethane as the source of both added ethyl chains (-CH(NHCH2CH3)CH3) to the Piperonal residue (3,4-MDPh-CH2-).

[ChemicalSolution]

If you think the ethylamine(HCl) formed during the Fe/HCl reduction to ketone will form the Schiff's base with the ketone, then purpose a procedure to try and SWIM will give her a shot.

[ChemicalSolution]

Swim sure doesn't understand the mechanism of the Fe reduction too well.. But Shulgin doesn't use HCl, just GAA.  What if the toluene solution from the nitroalkene synthesis is added to GAA along with the iron metal and the reduction is carried out by heating?

[Rhodium]

The Fe reduction mechanism goes like this if I remember correctly:

Phenyl-2-nitropropene [Ph-CH=C(NO2)CH3] is reduced by iron to Phenyl-2-nitrosopropene [Ph-CH=C(NO)CH3], and this is reduced further by the iron  into the oxime of Phenyl-2-propanone [Ph-CH2-C(=N-OH)CH3], which is then hydrolyzed by acid/water to Phenyl-2-propanone [Ph-CH2-C(=O)CH3].