i have tried this out a few times, but for it to work completely nice, one inconsistent thing in the paper needs to be made clear. maybe someone has
an idea what the authors mean in this passage:
"8 mL of a 0,5 M solution of Na2HPO4 in a 1 N solution of NaOH were added"
in HOW MUCH of 1N NaOH?
General procedures for the oxidation of secondary nitroalkanes: To a solution of 1 mmol of nitroderivative in 6 mL of MeOH, 8 mL of a
0,5 M solution of Na2HPO4 in a 1 N solution of NaOH were added.
After 1 h, 1 mmol of Oxone (R) in 3 mL of water was added to the stirred suspension. The resulting mixture was stirred at room temperature for 1 h,
then it was acidified with a 10% solution of HCl(why are they doing this? it could only protonate the unreacted nitronate)
and extracted with CH2Cl2. The combined organic layers were washed with brine, dried and evaporated.
The buffering of the reaction mixture in this procedure is vital for achieving good yields, because the nitronate is the active species, while the
stability of Oxone decreases with rising pH.
can anybody think of a suitably concentrated buffer, which prevents the need for huge reaction volumes?
Has anyone tried the nef reaction with K2CO3 and H2O2?
[Edited on 11-4-2007 by stoichiometric_steve]Klute - 11-4-2007 at 14:31
Quote:
Originally posted by stoichiometric_steve
"8 mL of a 0,5 M solution of Na2HPO4 in a 1 N solution of NaOH were added"
in HOW MUCH of 1N NaOH?
My guess would be that it's a solution in which there is 0.5mol of Na2HPO4 and 1mol of NaOH in a L... Not specially 8mL of 0.5M Na2HPO4 in XmL of
1M NaOH....
As for the acidification, I don't know. And the phosphate buffer is pretty effective, and generally used. I would stick with it the first few times at
least. Also, Oxone contains KHSO4 and K2SO4 whic act as buffers themselves.tupence_hapeny - 20-5-2007 at 18:31
Developments in the NEF (and associated) reactions
