SUBSTITUTED THIAZOLIDINYL ESTERS OF PHOSPHORIC ACID AMIDES AND PHARMACEUTICAL COMPOSITIONS

Compounds of the formula (I) in which one of the symbols R1 and R2 represents an alkyl radical that has 3 or 4 carbon atoms and is unsaturated in the 2,3-position, and the other represents such a radical or lower alkyl, R3 and R4 each represents, independently of the other, hydrogen or methyl, and A represents a radical of the formula in which Z1, or each of Z2 and Z3 independently of the other, represents hydrogen or lower alkyl, or Z2 and Z3 together represent lower alkylene, each of R5 and R6, independently of the other, represents hydrogen, lower alkyl, halogenated lower alkyl, or lower alkenyl or R5 and R6 together represent lower alkylene that is optionally interrupted by oxygen, sulphur or by optionally substituted nitrogen, and X represents OR7 or NR8R9 in which R7 represents hydrogen or lower alkyl and each of R8 and R9, independently of the other, represents hydrogen, lower alkyl, halogenated lower alkyl, or lower alkenyl or R8 and R9 together represent lower alkylene that is optionally interrupted by oxygen, sulphur or by optionally substituted nitrogen, or R6 together with R7 or R8 represents a lower alkylene group Alk, and salts of such compounds in which Z1, or Z3 and optionally also Z2, or R7 represent(s) hydrogen, exhibit tumor-inhibiting activities.