Structures of metabolites produced by blocked mutants of Microbispora rosea subsp. hibaria TP-A0121, hibarimicin-producer, were determined by spectroscopic analysis. HMP-Y6 is the dimer of the west half of hibarimicin B, the aglycon of which is the genuine biosynthetic intermediate. HMP-P1 is the shunt product arising from the release of a methanol molecule from hibarimicinone. HMP-P4, the glycoside of HMP-P1, is glycosylated with two amicetoses and two digitoxoses same as hibarimicin B. HMP-M1, M2, M3 and M4 are shunt products derived from the monomeric undecaketide intermediates.