Abstract: The invention relates to compounds of formula I ##STR1## in which formula X is hydrogen or hydroxy; Y is oxygen, sulphur, or oxidized sulfur (S(O) or S(O.sub.2)); R.sup.1 and R.sup.2, which may be the same or different, stand for hydrogen or C.sub.1 -C.sub.6 hydrocarbyl, or R.sup.1 and R.sup.2, taken together with the carbon atom (starred in formula I) bearing the group X, form a C.sub.3 -C.sub.8 carbocyclic ring; Q is a C.sub.1 -C.sub.8 hydrocarbylene diradical. R.sup.3 is hydrogen or C.sub.1 -C.sub.6 hydrocarbyl. R.sup.1, R.sup.2 and/or Q, may be optionally substituted with one or more deuterium or fluorine atoms; n is 0 or 1. The present compounds show antiinflammatory and immunomodulating effects as well as a strong activity in inducing cell differentiation and inhibiting undesirable proliferation of certain cancer and skin cells.

Abstract: This invention relates to vitamin D analogues represented by the general formula I ##STR1## in which formula X stands for hydrogen, lower alkyl, halogen or hydroxy; Y stands for hydrogen or hydroxy; R.sup.1 and R.sup.2, which may be the same or different, stand for lower alkyl, optionally substituted with halogen or hydroxy with the proviso that R.sup.1 and R.sup.2 cannot both be methyl when X is other than lower alkyl, or, taken together with the carbon atom numbered 25, R.sup.1 and R.sup.2 can form a saturated or unsaturated C.sub.3 -C.sub.9 carbocyclic ring which may optionally be substituted at any possible position(s) with lower alkyl, halogen or hydroxy; R.sup.3 stands for hydrogen or lower alkyl; R.sup.4 and R.sup.5 represent either each hydrogen, or when taken together constitute a bond, with the result that a double bond connects carbon atoms numbered 22 and 23; and bioreversible derivatives thereof.