Potential antitumor agents. 13. 4 Methyl 5 amino 1 formylisoquinoline thiosemicarbazone

Article abstract of DOI:10.1021/jm00229a023

4 Methyl 5 amino 1 formylisoquinoline thiosemicarbazone has been synthesized in an attempt to obtain (a) high affinity for the target enzyme ribonucleotide reductase, (b) water solubility as an acid salt of the amine, (c) steric protection of the amino group from in vivo acetylation, and (d) insensitivity to O glucuronidation, a major factor in inactivity in man of 5 hydroxy 2 formylpyridine thiosemicarbazone. The synthesis was achieved by nitration of 1,4 dimethylisoquinoline at the 5 position followed by selective oxidation with selenium dioxide to the corresponding 1 carboxaldehyde. The aldehyde group was protected by conversion to the cyclic ethylene acetal which was then catalytically reduced to produce the 5 amino derivative. Reaction with thiosemicarbazide in the presence of hydrochloric acid yielded the desired derivative. This agent was found to be an effective antineoplastic agent in mice bearing Sarcoma 180 ascites cells and at the maximum effective daily dose of 10 mg/kg increased the average survival of animals threefold over untreated tumor bearing controls.