[Newer antimycotics VI. 2-nitroaryl-hydrazones of nitromethanal (author's transl)].

The author investigated the coupling reactions of aryldiazonium salts with nitromethane and nitroethane and proved that only the coupling with 2-nitroaryldiazonium salts and their 4 substituted derivatives yields stable compounds. The author produced a number of nitromethanal-2-nitrophenylhydrazones and nitroethanal-2-nitrophenylhydrazones and investigated their fungistatic and fungicidal efficiency in vitro. For comparison sake he also investigated the fungistatic and fungicidal effect of 2-nitrophenylhydrazones of the cyanomethanal, mesoxalic-acid-dinitril, mesoxalic-acid-seminitril-ethylester and mesoxalic-acid-seminitril-amide because these compounds show a certain chemical analogy with nitromethanal-2-nitrophenylhydrazone. Simultaneously the author investigated the fungistatic and fungicidal effects of captan and thiram which represent two standard fungistatics in order to obtain comparable results. He proved that nitromethanal-2-nitrophenylhydrazone and its 4 substituted derivatives exert a widely spreading fungistatic effect. In contrast thereto the fungistatic range of nitroethanal-2-nitrophenylhydrazone is limited; only the trichophyton- and epidermophyton species are influenced by it. 2-Nitrophenylhydrazone of mesoxalic-acid-dinitril which bears an analogous structure to nitromethanal-2-nitrophenylhydrazone reveals fungistatic and fungicidal activity. Any further structurally analogous compounds of nitromethanal-2-nitrophenylhydrazones are totally ineffective on filamentous dermatophythons and also on phytopathogenic and saprophytic fungi strains. The author proved that the two standard fungistatics, captan and thiram, are on the whole as effective as nitromethanal-2-nitrophenylhydrazone as far as their fungistatic and fungicidal activities are concerned. The possibility of a practical administration of nitromethanal-2-ntrophenylhydrazones as fungistatics is discussed.