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I was told following:
With vigorous stirring, to 5ml of IPA / 1g of P2NP and 0.4 times volume of H2O in RBF was dumped 6 mol eq. of NaBH4.
Recrystallized P2NP was washed with sodium bisulfite solution, then with and water and it was then added in small portions to the mixture to minimize frothing. No external cooling applied. After all substrate was added and near-colourless solution is obtained, the solution left stirring for 30 minutes. Claisen adapter was fitted to the rbf with reflux setup and addition funnel. With one portion, 10%-mol equivalent (for the nitroalkene) of CuCl2.2H2O dissolved in IPA was added to the solution via the funnel. It was refluxed for 30 minutes. After which the remaining NaBH4 was destroyed by adding about 50% acetic acid untill the fizzing stopped and the solution was fairly acidic. With the claisen adapter still attaced, short path distillation setup was rigged and everything below 100'C was stripped.
Then the solution was made basic dripping strong NaOH solution to the reaction flask and steam distilled. Additional very dilute NaOH solution was added through the addition funnel every now and then. The distillate was then made slightly acidic with H2SO4 and evaporated.
Total yield after recrystallization: 80% mol wise from the P2NP due to very sloppy work
Functional groups can be reduced in the order of ketones > aromatic nitro groups > aliphatic esters > aliphatic nitros > nitriles > olefins. Dunno where to place the halogens though. But basically with methylamine or even nitromethane, you could reduce straight to methamphs as well. How neat is that :)
Notes: use pure IPA (without lubricants and shit like that), maybe ethanol (without mek etc ketones).. and remember to recrystallize the P2NP and/or wash it with sodium bisulfite to get rid of aldehydes. They interfere the reaction. Unfortunately, this reduction does not work with ring halogenations. It will efficiently reduce 4-chloro-2,5-diMeOP2NP to 2,5-DMA though..
The modification is based onISSN: 2231-1963
Please try it yourself and post your results :) I say: fuck the Zn/Al reductions, even though the Al-Cu or even Zn-Cu with formic acid works like a charm (and the yields are quite comparable). But too much work and hassle anyway. Btw, I use 4%-mol of CuCl2.2H2O for the zinc reductions with formic/potassium formate reactions.
http://www.sciencemadness.org/talk/files.php?pid=331291&aid=31340
