Abstract: Compounds having properties as inhibitors of protein synthesis are disclosed, of the general formula(p).sub.m --(5'--A--2'--p).sub.n --(A).sub.xwhereinp represents the phosphate group (orthophosphate),m is 0, 2, or 3A represents adenosine,n is from 2 to 5,x is 0 or 1,said compound containing at least three adenosine residues, the figures 5' and 2' signifying the carbon atoms of the ribose ring to which the respective phosphate groups p are attached.Compounds of particular interest are ApApA and its phosphorylated derivatives ppApApA and pppApApA. The substances may be prepared by chemical synthesis or enzymatic synthesis. They may be incorporated in liposomes.