No, i think you misunderstood
I don't know why they do the KMnO4-thing but i think H2O2 at RT is the oxidator.
What does worry me is that there aren't any yields stated.
I'm not that interested in acetaldehyde, since I could buy it too if i wish, but couldn't this be applied to more interesting alpha-amino acids like phenylalanine or, more interesting to me and the reason why it's in this forum, indole-3-acetaldehyde or I-3-acetic acid.
The reason why hypochlorite isn't a good way to go is because it will give a mixed product, the chloroamine and the dichloroamine, which decompose to the acetaldehyde and the nitrile respectively.
R-NH2-COOH + NaOCl ---> [R-NHCl-COONa + R-NCl2-COONa ]
------> R-CHO + R-CN (+ R-COOH, oxidation of aldehyde) + NH3 + CO2
As I told before, sodium-p-toluenesulfonylchloramide (used as 'Cloramine-T' as an aquarium desinfectans) seems much more feasible oxidation agent, as 1 mol gives the aldehyde and 2 mol gives the nitrile in good yields (see example above in this thread). What worries me here again is the fact that no yields are stated for the aldehyde, only an isolation procedure. Aldehydes are very reactive so that's why part of it, especially in the case of H2O2, oxidises further into the acetic acid.
BUT that's exactly the beauty here. Indole-3-acetaldehyde is a very unstable critter which could only be stored as the bisulphite addition product, and must be a pain in the ass to work with. But couldn't this be oxidised further in the same reaction vessel, eg. by using a molar excess of oxidation agent, to give (almost) only indole-3-acetic acid?
ref is:
H. DAKIN, Journal of Biological chemistry, 1916, p.319
For more details about the chloramine-T reaction i wil dig up this one next week:
PROC.ROY.SOC.B. 89,232 (1916), H.D.DAKIN
Well, I mean, there must be SOMEONE interested in an OTC tryptophan --> I-3-acetic acid way
e109