New synthons and application thereof for the preparation of 19-nor vitamin D derivatives

Przedmiotem wynalazku jest synton przedstawiony wzorem (I), w którym R1 i R2 są takie same lub różne i niezależnie oznaczają atom wodoru lub grupę zabezpieczającą funkcję hydroksylową i jego zastosowanie do syntezy pochodnych 19-nor witamin D. The present invention discloses the synthone of Formula (I), wherein R1 and R2 are the same or different and represent independently hydrogen atom or hydroxyl protecting group, and its use for preparation of 19-nor vitamin D derivatives of general Formula (IV), wherein represents single or double bond, p represents an integer 0 to 3, R1 and R2 represent independently hydrogen atom or hydroxyl protecting group, R3 represents hydrogen atom, CH3 or hydroxyl group, R4, R5 and R6 represent independently hydrogen atom, C1-C3-alkyl or hydroxyl group or two of R4, R5 and R6 substituents altogether form cyclopropyl group, in particular for preparation of paricalcitol.