DL-Ephedrine → Pseudoephedrine

HRID 1089657

Reaction equation

[CH3:1][CH:2]([NH:11][CH3:12])[CH:3]([OH:10])[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.CN.C[C@H](NC)[C@H](O)C1C=CC=CC=1>>[CH3:1][C@H:2]([NH:11][CH3:12])[C@@H:3]([OH:10])[C:4]1[CH:5]=[CH:6][CH:7]=[CH:8][CH:9]=1

Participants

Reactant 3

HCID 5032DL-Ephedrine2×

HCID 6329Methylamine

HCID 9294Ephedrine

Product 1

HCID 7028Pseudoephedrine

Procedure

The combination of yeast transformation of benzaldehyde to produce PAC and chemical conversion of the PAC to make 1-ephedrine is described in U.S. Pat. No. 1,956,950. The PAC can be converted by a chemical reductive amination with methylamine to optically pure L-ephedrine as follows: ##STR2## The 1-ephedrine can then converted in high yield to d-pseudoephedrine as follows: ##STR3## It is apparent from this reaction scheme that microbial transformation of benzaldehyde by yeast to form L-(-)phenyl acetyl carbinol in high yield and purity is of prime importance for successful commercial operation of the synthetic route.

Sources & evidence

ORD record: ord-c9ee2c214413439988f36bc372be76e0
Source dataset: uspto-grants-1992_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05079145

Linked notes

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