NEW MATERIAL:A compound shown by formula I {R1 and R2 are H, -COOR [R is (substituted) lower alkyl or (substituted) lower alkyl] or acryl group obtained by removing hydroxy part from carboxyl group of amino acid (amino group or side-chain carboxyl group may be protected) with the proviso that R1 and R2 are simultaneously not H}.

EXAMPLE: 11,15-Di-O-methoxycarbonyl-hitachimycin.

USE: An antitumor agent having antimicrobial and antitumor activity.

PREPARATION: For example, hitachimycin shown by formula II is reacted with an acid halide shown by the formula ROCOHal (Hal is Cl or Br) in the presence of a base in an inert solvent to give a compound shown by formula III (R1a=R2a), one of compounds shown by formula I.