Search for physiologically active compounds. Part XII. Synthesis and fungistatic activity of 5:6- and 5:8-quinoline quinone

A few 5:6- and 5:8-quinoline quinones have been synthesised by oxidising the corresponding aminohydroxy and diaminoquinolines. The required aminohydroxy quinolines could be prepared by nitrosation of hydroxy quinolines and subsequent reduction. Coupling the monoamino quinolines with diazotised sulphanilic acid and reduction afforded the diamino quinolines. 6:7-dichloro- and 6:7-dibromo-5:8-quinoline quinones exhibited fungistatic activity nearly equal to that of 2:3-dichloro-1:4-naphthoquinone