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Hydrogenolysis of Phenylalaninol.....

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java:
In mining through the large archives here at the hive I read  Post 108597 (missing) (dormouse: "drone's amphetamine synthesis contest  -drone 342", Novel Discourse) from which psychokitty contributes to the amphetamine contest where she introduces her way to Methamphetamine starting with Phenylalanine .....anyway read it yourself but the point is a reference which she gives ,
Hydrogenolysis of Diaryl and Aryl Alkyl Ketones and Carbinols by sodium Borohydride and anhydrous Aluminum(III) chloride

AoiOno, Nobuko Suzuki, Junko Kamimura



for which deals with the reduction, to the respective Hydrocarbons, of Phenylalaninol alcohols  but it also works for the benzylic alcohols in ephedrine and Pseudoephedrine and phenylpropanolamine. One thing also she discusses the acylation of the amine prior to reduction to the alcohol in order to obtain at the end methamphetamine. Thank you psychokitty for your research........java

java:
Syntheses of Amino Alcohols and Chiral C2-Symmetric Bisoxazolines
Derived from O-Alkylated R-4-Hydroxyphenylglycine and S-Tyrosine

Vesna ^aplar,a,* Zlata Raza,b Darinka Kataleni},a and Mladen @ini}a

CROATICA CHEMICA ACTA CCACAA 76 (1) 23-36 (2003)
ISSN-0011-1643
CCA-2849



Abstract

Chiral C2-symmetric bisoxazolines 1b–f and 2b,c, derived from 4’-O-alkylated R-4-hydroxyphenylglycine or S-tyrosine, were prepared. As intermediates, a series of chiral amino alcohols
possessing substituted phenolic groups was prepared and fully characterized.

CONCLUSION
Chiral amino alcohols with free and substituted (alkyl,benzyl) phenolic groups have been prepared in high yields, using easily available reagents and mild conditions. They served as precursors for the preparation of either macrocyclic or acyclic chiral C2-symmetric bisoxazolines, designed
as ligands for metal-catalyzed enantioselective transformations.

josef_k:
for which deals with the reduction, to the respective Hydrocarbons, of Phenylalaninol alcohols  but it also works for the benzylic alcohols in ephedrine and Pseudoephedrine and phenylpropanolamine. One thing also she discusses the acylation of the amine prior to reduction to the alcohol in order to obtain at the end methamphetamine. Thank you psychokitty  for your research........java
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I wonder if it really works with ephedrine and related compounds. The article says they think the reduction works by first reducing the ketone to the benzylic alcohol, which is then dehydrated to the alkene, which is then further reduced to the alkane. But in the case of ephedrine the doublebond may migrate to make an imine, which could be hydrolized if you're unlucky. (See https://www.thevespiary.org/rhodium/Rhodium/chemistry/phenylacetone.html#ephedrine)
But who knows if it will work until someone has tried it.  :)

java:
.....but in the case of ephedrine the doublebond may migrate to make an imine, which could be hydrolized if you're unlucky
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josef_k At most the activity in the hydrogenolysis would be around the -OH making it an easier leaving group for the catalyst action of NaBH4 , however I don't see how it would revert to a double bond intermediate to reduce to its hydrocarbon.....unless you think there may be some activity with the methylamine group for which I doubt . The main activity with the Aluminum would be with the O.........java

armageddon:
Java: Water is out of the question because of thionyl violent reaction to water , hence I need something that will put the alcohol in solution so it can react with the acid.

I thought of using chloroform, as I've used this in the reduction of ephedrine and pseudoephedrine to a chloroephedrine, but not sure that the alcohol will work in this solvent. I guess I will try a small sample for solubility.


For dehalogenations, DCM and chloroform are a good choice - but for hydrogenations, alcohols (maybe with additional acetic acid) are the solvents to be used with Pd/C...

http://www.strem.com/code/degussakit.html


Greetz A

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