Characterization of hydrazine derivative: proposed decomposition mechanism and structure elucidation of decomposition compounds.

Decomposition of protected hydrazine diol (1) hemi-oxalate, a key intermediate of the potent indolocarbazole-based DNA topoisomerase I inhibitor (2), was investigated. Spectroscopic analysis revealed that the main decomposition compounds of the hydrazine derivative were a peroxide (3) and an alcohol derivative (4). The peroxide derivative (3) was proposed to form in the presence of oxygen- and/or H(2)O-generated radicals, which was subsequently reduced to the more stable alcohol derivative (4). A plausible decomposition mechanism was proposed and our findings were substantiated by chemical conversion.