In vitro antimycobacterial activities of pyrazinamide analogs.

We synthesized various pyrazine derivatives and pyrazinamide analogs and assayed their antimycobacterial activities in vitro in order to find new drugs which are more active against Mycobacterium tuberculosis than pyrazinamide and also active against Mycobacterium avium and Mycobacterium intracellulare. Of the drugs synthesized, four drugs, namely, pyrazine thiocarboxamide, N-hydroxymethyl pyrazine thiocarboxamide, pyrazinoic acid n-octyl ester, and pyrazinoic acid pivaloyloxymethyl ester, were not only bacteriostatic but also bacteriocidal against these three species of mycobacteria in vitro under conditions in which pyrazinamide showed no or little activity. In conclusion, these four drugs are possible candidates for new antimycobacterial agents, and animal experiments are now under way.