Abstract: Novel compounds ##STR1## wherein R.sup.1 to R.sup.13 are independently selected from C.sub.2 -C.sub.4 linear and branched alkyls, H, NH.sub.2, CH.sub.3, OR.sup.14, fluorine, chlorine, iodine, NO.sub.2, CF.sub.3, NHCOCH.sub.3, NHCOOtBu, NHR.sup.15, NR.sup.16 R.sup.17 and phenyl, for use as immunosuppressive agents to prevent or significantly reduce graft rejection in organ and bone marrow transplantation are described. The novel compounds can also be used as an immunosuppressant drug for T-lymphocyte mediated autoimmune diseases, such as diabetes, and may be useful in alleviating psoriasis and contact dermatitis. Additionally, the novel compounds can be used for antiproliferation and gene therapy.