The present invention provides compounds of the general formulae: ##STR1## wherein R.sub.1 and R.sub.2, which can be the same or different, are hydrogen atoms or C.sub.1 -C.sub.5 -alkyl radicals, C.sub.3 -C.sub.5 -alkenyl radicals or phenyl radicals or, together with the carbon atom to which they are attached, form a saturated or unsaturated C.sub.3 -C.sub.7 ring, R.sub.3 and R.sub.4, which can be the same or different, are hydrogen atoms, straight-chained or branched C.sub.1 -C.sub.10 -alkyl radicals, straight-chained or branched C.sub.3 -C.sub.7 -alkenyl radicals, C.sub.3 -C.sub.7 -cycloalkyl radicals, C.sub.3 -C.sub.7 -cycloalkenyl radicals, phenyl, arylalkyl or hetarylalkyl radicals, R.sub.5 is a hydrogen atom or a lower alkyl radical and X is an oxygen or sulphur atom or an imino group. The present invention also provides processes for the preparation of these compounds, as well as pharmaceutical compositions with immunosuppressive action containing them.
本发明提供了一般式为:##STR1## 的化合物,其中R.sub.1和R.sub.2可以相同也可以不同,是氢原子或C.sub.1-C.sub.5-烷基基团,C.sub.3-C.sub.5-烯基基团或苯基基团,或者与它们连接的碳原子一起形成饱和或不饱和的C.sub.3-C.sub.7环,R.sub.3和R.sub.4可以相同也可以不同,是氢原子,直链或支链的C.sub.1-C.sub.10-烷基基团,直链或支链的C.sub.3-C.sub.7-烯基基团,C.sub.3-C.sub.7-环烷基团,C.sub.3-C.sub.7-环烯基团,苯基,芳基烷基或杂芳基烷基基团,R.sub.5是氢原子或较低的烷基基团,X是氧原子或
硫原子或
亚胺基。本发明还提供了制备这些化合物的方法,以及含有免疫抑制作用的制药组合物。