abstract |
The present invention relates to a method for preparing a vitamin D 3 compound of formula (I):n n n n n n n n n n Wheren n n A is a single or double bond,n n n B is a single, cis-double, trans double or triple bond,n n n R 1 and R 2 are independently hydrogen or C 1 -C 4 alkyl,n n n R 3 and R 4 are independently C 1 -C 4 alkyl, hydroxyalkyl or haloalkyl. |