Hi bees!
My buddy (whose name is replaced with SWIA for anonymity reasons
) was curious about the usability of sodium dithionite for reducing P2NP to phenylacetone oxime, like posted by Barium in
Post 427794
(Barium: "Nitrostyrenes to oximes with sodium dithionite", Novel Discourse) - but when trying the described procedure he just ended up with some carbonate salt, so a different workup was used..
First he reduced the nitropropene as follows: in a 500ml RBF he placed 16.3g P2NP, wetted it down with 30ml EtOH and placed this on a water bath at 50°C. then, he added 50.6g Na2S2O4 (86% purity) and 100ml water and started stirring. After a few minutes, the temp. of the yellowish solution quickly rose to >70°C while the color disappreared almost completely. The heating bath was changed with a cooling bath (10°C) and the reaction was allowed to cool down to ~30°C.
Then SWIA added 100ml H2O, basified with conc. NaOH-solution to above pH10 and extracted three times with ethyl formate, washed the combined organic extracts with aequous NaOH, then 2x with brine, dried over Na2SO4 and removed the ethylformate by distillation under reduced pressure (200torr), leaving a pale cream-colored oil that slowly solidified on cooling (...it actually did so after 3 days).
Unfortunately he spilled a good amount of the ethylformate/oxime solution, so yields could not be taken - but the oxime is for sure free from carbonates and foul sulfurous smell!
SWIA told me he would try it again to be able to calculate yields... Of course I will post them as soon as I hear about it!
Note: SWIA told me one could also substitute the 30ml's alcohol with 20ml ethylacetate - it facilitates extracting the oxime afterwards, but the rxn time is lenghtened...
Greetz A
