A mixture of 400 mg (1.4 mmol) of 10-chloro-8-hydroxy-11H-indeno[1,2-b]quinolin-11-one, 629 mg (8.5 mmol) of lithium carbonate, 963 mg (5.7 mmol) of 2-diethylaminoethanethiol hydrochloride and 8 ml of N,N-dimethylformamide was stirred for 5 hours with heating at 90° C. After completion of the reaction, the reaction mixture was added to water, and precipitated crystals were collected by filteration. The crystals were recrystallized from ethanol, giving 310 mg of the title compound (yield: 57.7%). The property values are shown in Table 1.
