Abstract: Compounds of formula I ##STR1## in which R denotes a straight-chain or branched, saturated or unsaturated aliphatic hydrocarbon radical having 6-30 C atoms wich may optionally be substituted by halogen or the radicals OR.sub.1, SR.sub.1 or NR.sub.1 R.sub.2, where R.sub.1 and R.sub.2 in each case denote a hydrogen atom or an alkyl or acyl radical having 1-6 C atoms which have excellent virustatic and cytostatic action.

Abstract: The invention relates to novel glycero-3(2)phospho-L-serine derivatives of the general formula ##STR1## in which A represents unsubstituted or substituted (C5-C30) alkoxy, or unsubstituted or substituted (C5-C30) alkenoxy, whereby a double bond of the alkenoxy residue does not originate at the C atom bound to oxygen, or halogen, or a group of the general formula--O--(CH.sub.2).sub.n --CF.sub.3 II,wherein n is 0 or an integer 1, 2 or 3, one of the two residues B and C, which is identical to or different from A, has one of the definitions given for A or represents hydrogen, and the respective other residue represents the phosphatidyl-Lserine group of the formula ##STR2## with the proviso that at least one residue A, B or C represents (C5-C30) alkoxy or (C5-C30) alkenoxy; and the pharmaceutically acceptable salts of compounds of general formula I with bases, a process for the preparation thereof, pharmaceutical preparations containing the said compounds, and their use in drugs with cytostatic activity.