Duphar International Research Bv

Ire-medgenix S.a.

Pierre J De Clercq

Maurits E Vandewalle

Luc J Vanmaele

Sebastianus J Halkes

Roger Bouillon

Wilhelmus R Overbeek

Pierre Eliard

Vitamin D derivatives corresponding to the following formula I ##STR1## in which R.sub.1 denotes a substituted alkyl group having 1 to 15 carbon atoms, in particular the side chains of vitamin D.sub.2 (C.sup.20 to C.sup.28) or D.sub.3 (C.sup.20 to C.sup.27), or these same chains partially modified,

Vitamin D derivatives: therapeutic applications and applications to

The invention relates to a method of preparing 1 .alpha.-hydroxyvitamin D or 1 .alpha.-hydroxy-previtamin D compounds by hydroxylating the 1 .alpha.-position of an adduct of a previtamin D compound with a suitable dienophile, in which adduct optionally present hydroxy group or hydroxy groups is or are protected, if desired, and after removal of the protecting group or groups, isolating the 1 .alpha.-hydroxyvitamin D or 1 .alpha.-hydroxy-previtamin D compound. The invention also relates to 1 .alpha.-hydroxy-previtamin D compounds. The invention further relates to an adduct of a previtamin D or tachysterol compound with a dienophile of the general formula ##STR1## in which A' and B' are equal and represent methoxy groups or ethoxy groups, or in which A' and B' together constitute a phenylimino or o-phenylene group.

Method of preparing 1 .alpha.-hydroxyvitamin D and 1

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Gent, Belgium

Pierre J De Clercq