The title of this thread is not entirely accurate because I will also share references for the artificial synthesis of some naturally occuring
compounds.
Sometimes the synthesis is much more convenient than the isolation from natural sources.
Schoenberg (1952) reviews the Strecker degradation of alpha-aminoacids. The paper is in English, as is Tolkachev's.
This reaction, under adequate conditions, converts:
A) phenylalanine into phenylacetaldehyde, which can easily be oxidized to phenylacetic acid.
B) glutamic acid (Ajinomoto) into 3-aldehydopropionic acid, (X) which, being troublesome to isolate, is best reacted with something. Sodium
dithionite, (Na2S2O4) for example, reduces aldehydes to alcohols without touching carboxylic acids. It probably can convert X into
gamma-hydroxybutyric acid.
Sodium dithionite is easy to prepare from Na2CO3, SO2, and sodium formate. SO2 can be made by burning sulfur in a special equipment, or by heating
concentrated H2SO4 and Cu. References for the preparation of formic acid can be found here:
http://www.sciencemadness.org/talk/viewthread.php?tid=19639
Glutamic acid can be isolated from wheat gluten, and phenylalanine can be isolated from egg white. More on this latter.
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