酸性actinomycin類縁物質B-1625 FA3βのactinomycin X2への変換

The active component of acidic actinomycin congener B-1625 FA was obtained by exclusion column chromatography with Diaion HP-20 SS and aluminium oxide TLC, and was considered to be the B-1625 FA3β already reported. After repeated fractionations by aluminium oxide TLC, its FAB-MS spectrum showed the ion peak at m/z M+1 1269, C62H85O17N12 except at m/z M+1, 1343, C64H87O20N12. During the purification procedure, FA3β was found to be converted to another active product in alkaline solution. The conversion product FA-n1 obtained as a bright orange rhombic crystal was identified with actinomycin X2 (m/z M+1, 1269, C62H85O17N12). Thus FA3β was presumed to be weakly acidic by the substitution of one proton of actinomycin X2 by the group of C2H2O3.