PURPOSE: To photochemically convert a tachysterol compound and a trans-vitamin D compound into a previtamin D compound and a cis-vitamin D compound, respectively, by the use of a specific polymeric photosensitizer such as a photosensitizer having a polyoxy 2-6C alkylene chain by the irradiation with light having a specific range of wavelength.
CONSTITUTION: A tachysterol compound and a trans-vitamin D compound dissolved in a solvent system are converted into a previtamin D compound and a cis-vitamin D compound, respectively, by the irradiation with light having a wavelength of about 300-about 1,000 nm by using a polymeric photosensitizer whose polymer chain has been selected from the group consisting of a polyether chain, an amino group-containing polymer chain and a copolymer chain comprising polyether segments and/or amino group-containing polymer segments in such a manner that the polymeric photosensitizer dissolves in the solvent system during the exposure to irradiation but either upon cooling precipitates from the solution and can be isolated, or, in case the polymer chain comprises amino groups, can be protonated with a suitable acid substance and then, can be removed in an post-treatment.
SEBASUCHIYANUSU JIEI HARUKESU
ROBERUTO BII KOORUSUTORA
