Method for the photochemical conversion of tachysterol compounds into previtamin D compounds and of trans-vitamin D compounds into cis-vitamin D compounds using a polymeric photoinitiator
US5175217A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 23, 1990 |
| Grant date | Dec 29, 1992 |
| Priority date | — |
| Expiry date | Aug 23, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G65/337
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The invention relates to a method for the photochemical conversion of tachysterol compounds into previtamin D compounds and of trans-vitamin D compounds into cis-vitamin D compounds under the influence of radiation, by exposing the tachysterol compound and trans-vitamin D compound, respectively, dissolved in a suitable solvent system, in the presence of a polymeric photosensitizer consisting of a polymer chain ("backbone") comprising covalently bound sensitizers suitable for the photochemical conversion, to light with a wavelength of preferably between approx. 300 and approx. 1,000 nm, and by then isolating the resulting previtamin D compound and cis-vitamin D compound, respectively, in which a polymeric photosensitizer is used, the polymer chain of which has been selected from the group consisting of a polyether chain, an amino groups-containing polymer chain and a block copolymer chain comprising polyether segments and/or amino groups-containing polymer segments, in such a manner that the polymeric photosensitizer dissolves in the solvent system during the exposure to radiation but either upon cooling precipitates from the solution and can be separated, or, in case said polymer c…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.