structure iii a new synthetic route has been developed starting from a methyl quinicate derivative which is easily obtained from commercial 1r 3r 4s 5r u2212 quinic acid as described by perlman et al tetrahedron lett 32 7663 1991 and deluca et al u s pat no 5 086 191 the overall process of the synthesis of compound i is illustrated and described more completely in u s pat no 5 843 928 issued dec 1 1998 and entitled u201c 2 alkylidene 19 nor vitamin d compounds u201d the specification of which is specifically incorporated herein by reference the introduction of a methylene group to the 2 position of the 20 s isomer of 19 nor 1 25 oh 2 d 3 had little or no effect on binding to the porcine intestinal vitamin d receptor this compound bound equally well to the porcine receptor as compared to the standard 1 25 oh 2 d 3 fig1 it might be expected from these results that this compound would have equivalent biological activity surprisingly however the 2 methylene and 20 s substitutions produced a highly selective analog with its primary action on bone fig2 shows that 2md has activity similar to that of 1 25.