Abstract: The compounds of the Formula (I) ##STR1## wherein R.sub.1 is a C.sub.18-24 alkenyl containing at least two double bonds, or --(CH2)n --CH(NH2)m --COOHX is 0, NH or C.sub.1-4 alkyl-N,Y is CONH.sub.2, COOH or COOMe, wherein Me is hydrogen metal, andR.sub.2 is a side chain of a any amino acid except L-GLU or L-ASP at .alpha.-position or a group of Formula--(CH.sub.2).sub.k --C.sub.6 H.sub.3 --(A).sub.2 (II),--(CH.sub.2).sub.n --X--(CH.sub.2).sub.m --X--M (III)whereink is zero or an integer of 1,n is zero or an integer of 1 to 3,m is zero or an integer of 1 to 4,A is hydroxyl or one A is hydroxyl and the other A is hydrogen.M is H or R.sub.1 --CO andX and R.sub.1 are as defined aboveand their salts having tyrosine kinase inhibitor activity can be used as antitumor agents.