myr
Harmless
Posts: 48
Registered: 18-7-2018
Member Is Offline
|
|
Aspartic Acid Degredation Failure
The following procedure, from the paper 'Biobased synthesis of acrylonitrile from glutamic acid' was attempted on aspartic acid bought as a
supplement, advertised as pure aspartic acid with no filler, in the hopes of getting cyanoacetic acid.
However, at the endpoint there was a substantial amount of white ppt, insoluble in the media which did not react with further bleach (therefore not
any possible starting or end products/side products afaik). A starting 3.33g of the amino acid had 2.4g (once dried) of this material- an apparent
filler.
Moral of the story? Don't trust Amazon supplements I guess.
| Quote: |
n an ice-bathed round bottom flask were introduced glutamic acid (2.93 g, 20 mmol), NaBr (0.21 g, 10 mol%), and 50 mL H2O. NaOCl solution (15 wt% in
H2O, 24.8 mL, 60 mmol) was added dropwise under a good stirring (for each drop of NaOCl solution, the reaction mixture turned orange and
a strong CO2 evolution was observed while the coloration disappeared). After 1 hour stirring at 4 oC the reaction mixture was carefully
quenched with Na2S2O3.5H2O. NaCl was then added till saturation and the reaction mixture was extracted with Et2O (4 x 30 mL). The
collected organic layers were dried over MgSO4 and evaporated to dryness. 1H NMR analysis of the crude showed 3-cyanopropanoic acid (5,
850 mg, 43% yield) as the major product and the corresponding aldehyde as a minor product (85% purity). A 94% purity towards 3-cyanopropanoic acid (5)
was obtained after one recrystallisation in Et2O. An alternative work-up procedure consisted in evaporating the water after reaction and
quenching. The resulting paste was extracted with Et2O (4 x 30 mL), the collected organic layers were dried over MgSO4 and evaporated to
dryness. NMR analyses of the crude showed 3-cyanopropanoic acid (5, 1.39 g, 70% yield, 90% purity). |
|
|
|
myr
Harmless
Posts: 48
Registered: 18-7-2018
Member Is Offline
|
|
The reaction did work at first, transient orange color and lots of gas emitted.
Has anyone tried this reaction on aspartic acid with success- and thus worth buying real aspartic acid? Or should I just purchase cyanoacetic
acid/cyanoacetate? The end goal was to produce a set of substituted cinammonitriles.
|
|
|
G-Coupled
Hazard to Others
Posts: 287
Registered: 9-3-2017
Member Is Offline
Mood: Slightly triturated
|
|
I'd try again with some hopefully pure Aspartic Acid from another supplier if it's not too expensive to get wrong. It's a cool experiment just to see
if it can be done IMO.
[Edited on 28-11-2019 by G-Coupled]
|
|
|
Boffis
International Hazard
Posts: 1836
Registered: 1-5-2011
Member Is Offline
Mood: No Mood
|
|
Somewhere on the SM web site there is a post from (IIRC) AvBaeyer that states that aspartic acid does not yield cyanoacetic acid by this type of
degradation. However, I have found that glutamic acid gives reasonable yields of cyanopropanoic acid providing that the reaction doesn't become to too
acid, too basic or too warm. The Goldelocks zone appears to be ph7 at -10 to 0 C. I am currently working on this reaction. If I can find the right
conditions then I'll try it on aspartic acid.
pH control is everything!
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
