Dolastatin-10 derivative, production process thereof and anticancer drug composition containing the same

Dolastatin derivative-10, represented by chemical formula I: pharmaceutically acceptable ** ** Formula or salt thereof, in / wherein R1, R2, R3, R4, and R5 are each independently hydrogen or C1 C4, R6 is hydrogen, hydroxy, C1-C4, amino, oxo (> = O) or hydroxyimino (> = N-OH), Ar is aryl, X is a carbon atom, oxygen or sulfur and R7 is hydroxy, amino, C1-C4 alkyl, C1-C4 alkylamino, or oxo (> = O) when X is a carbon atom, and is absent when X is an oxygen atom or sulfur.