Various substituted isoquinoline-1-carboxaldehyde thiosemicarbazones (12 compounds) have been synthesized and evaluated for antineoplastic activity in mice bearing the L1210 leukemia. Condensation of 4-bromo-1-methylisoquinoline (4) with ammonium hydroxide, methylamine, ethylamine, and N-acetylethylenediamine gave the corresponding 4-amino, 4- methylamino, 4-ethylamino, and 4-N-(acetylethyl) amino derivatives, which were then ...