Synthesis and pharmacological properties of some 7H-[1] benzothiopyrano-[3,2-c] quinolin-7-ones.

The title compounds 3a-d were prepared by intramolecular cyclization of 2-[S-(quinolyl-4)]-thiobenzoic acids 2a-d. The effects of 3a-d on the central nervous system were tested. Among the investigated benzothiopyranoquinolinones, the 2-chloro-6-methyl-derivative (3c) showed analgesic activity in the hot-plate and the writhing tests in doses over 100 mg/kg. Among known, biologically active polycyclic heterocyclic systems [1], benzothiopyranoquinolinones with variously condensed heterocyclic rings, have received little attention. 7H-[1] Benzothiopyrano [3,2-c] quinolin-7-one (3a) is an example of one of the four possible isomers in such systems. In continuation of our search for new centrally active compounds [12], we report here the synthesis and characterization of the parent system 3a and its three derivatives 3b-d. Since some thioxanthene derivatives [9] are known to be neuroleptic drugs, and few known in literature compounds [2, 13, 20] derived from the 3a system have not been tested pharmacologically for the central nervous system activity, we decided to investigate the influence of [1]-benzothiopyranoquinolinones 3a-d on the central nervous system of mice. The results of pharmacological screening are presented in this paper.