Development of an Improved Process for Doxercalciferol via a Continuous Photochemical Reaction

Doxercalciferol (1 alpha-hydroxyvitamin D2) is a commercially approved vitamin D derivative used to treat chronic kidney disease (CKD) patients whose kidneys cannot metabolically introduce a hydroxyl group at C1. A new process for the production of doxercalciferol from ergocalciferol was developed using a continuous photoisomerization of a known vitamin D intermediate as the key step, thus circumventing the limitations of batch photoisomerization processes. Doxercalciferol is produced in an overall yield of about 10% from ergocalciferol.