Direct chromatographic resolution and isolation of the four stereoisomers of meta-hydroxyphenylpropanolamine

✍ Scribed by Marcian E. Van Dort

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 95 KB
• Volume: 11
• Category: Article
• ISSN: 0899-0042
• DOI: 10.1002/(sici)1520-636x(1999)11:9<684::aid-chir3>3.0.co;2-4

✦ Synopsis

Methods for the direct chiral chromatographic separation of the four stereoisomers of meta-hydroxyphenylpropanolamine (MHPA) on an analytical and preparative scale are described. Separations were carried out on a Crownpak CR (+) chiral column with 113 mM aqueous perchloric acid as the mobile phase. Baseline resolution of the more retained (+)-stereoisomers (1S configuration) and partial resolution of the less retained (-)-stereoisomers (1R configuration) were obtained under these chromatographic conditions. Removal of the bulk of the (1R,2S)-stereoisomer (metaraminol) from the initial crude mixture by fractional crystallization as the (+)-bitartarate salt substantially improved the peak resolution factors (Rs) of the remaining three stereoisomers. Semipreparative chromatographic resolution of the latter isomeric mixture provided milligram quantities of each stereoisomer in >97% enantiomeric excess. Subsequent recrystallization of their bitartarate or fumarate salts gave enantiomeric purities >99%.