Purification process
US5917086A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 9, 1998 |
| Grant date | Jun 29, 1999 |
| Priority date | — |
| Expiry date | Jan 9, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C227/38
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A method for the purification of a keto acid having the general formula ##STR1## wherein R1 and R2 independently represent a straight or branched chain alkyl of 1-18 carbon atoms, a cycloalkyl of 4-8 carbon atoms or a phenyl both of which may be substituted by at least one substituent selected from the group consisting of halogen atoms and alkyls having 1-4 carbon atoms, an aralkyl of 7-10 carbon atoms, alkoxyalkyl having 2-20 carbon atoms, tetrahydrofuryl alkyl, alkylcarboxy alkyl, alkyl carboxy benzyl, or R1 and R2 together with the adjacent nitrogen atom may form a heterocyclic ring, or one of R.sub.1 and R.sub.2 is hydrogen, which comprises slurrying the keto acid with an alcohol solvent, maintaining the slurry at elevated temperature in a sealed vessel until the Rhodamine impurity has dissolved, cooling and isolating the pure keto acid by filtration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.