2-alkylidene-19-nor-vitamin d compounds

The invention provides a new class of compounds related to vitamin D, that is, derivatives of 2-alkylidene-19-norvitamin D, as well as a general procedure for their chemical synthesis. The compounds have the formula (I) * formula * in which Y {sub, 1} and Y {sub, 2}, which may be the same or different, are each selected from the group consisting of hydrogen and a hydroxy protecting group , R {sub, 6} and R {sub, 8}, which can represent the group - {(} CH {sub, 2} {{sub, x} -, where x is an integer from 2 to 5, and representing the R groups any of the typical side chains known for vitamin D type compounds. These 2-substituted compounds are characterized by low intestinal calcium transport activity and high bone calcium mobilization activity, resulting in new therapeutic agents for the treatment of diseases in which bone formation is desired, particularly in osteoporosis of low bone turnover. These compounds also exhibit pronounced activity in arresting the proliferation of undifferentiated cells and in inducing their differentiation to monocytes, thus evidencing their use as anticancer agents and for the treatment of diseases such as psoriasis.