Oxazolinium salts and method of preparation
US4237304A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 26, 1978 |
| Grant date | Dec 2, 1980 |
| Priority date | — |
| Expiry date | Oct 26, 1998 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D263/10
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
1-Aryl-1-hydroxy-2-methylaminopropanes are rearranged from the erythro isomer to the threo isomer by the process of (1) forming the O,N-diacyl derivative of the arylpropanolamine; (2) reacting the product of step (1) with an anhydrous or substantially anhydrous protic acid (thereby forming a novel oxazolinium salt); and (3) reacting the oxazolinium salt from step (2) with an aqueous protic acid. The threo isomer of the arylpropanolamine is thus produced as an amine/acid salt. This salt can be further purified, if desired, by neutralizing the acid/amine salt with caustic isolating the free amine and reprotonating the free base in isopropanol with, for example, anhydrous HCl. This process is particularly applicable to manufacture of d-pseudoephedrine from 1-ephedrine.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.