Bitertanol is a mixture of four isomers, which are chemical compounds belonging to the triazole and biphenyl derivative classes.
Synthesis and Preparation Bitertanol can be prepared via a multi-step reaction starting from 3,3-dimethyl-2-butanone: chlorination with elemental chlorine is followed by nucleophilic substitution of the chlorine atom with 4-phenylphenol, bromination with elemental bromine, subsequent nucleophilic substitution with 1,2,4-triazole, and final reduction of the ketone with hydrogen.
Properties Bitertanol is a colorless, water-insoluble solid. The commercial product is a 20:80 mixture of the (1RS,2RS)- and (1RS,2SR)-isomers.
It is highly stable toward photolysis and hydrolysis.EFSA: Conclusion on the peer review of the pesticide risk assessment of the active substance bitertanol, 2010. Its half-life in aqueous suspension is 39.2 days.F. Müller, P. Ackermann, P. Margot: Fungicides, Agricultural, 2. Individual Fungicides. In: Ullmanns Enzyklopädie der Technischen Chemie. Wiley-VCH, Weinheim 2012, .
Uses Bitertanol is used as a fungicide for the preventive or curative treatment of diseases in fruit and vegetable crops, including Venturia species and Monilia laxa in stone fruit, as well as a seed treatment against Fusarium, Septoria, wheat scab, and other pathogens.FAO: Bitertanol (PDF; 548 kB). It was introduced to the market in 1979 by Bayer AG.
Approval The European Union approved its use as an active substance in plant protection products, effective January 1, 2012, specifically as a fungicide for seed treatment.Durchführungsverordnung (EU) Nr. 1278/2011 der Kommission vom 8. Dezember 2011 zur Genehmigung des Wirkstoffs Bitertanol gemäß der Verordnung (EG) Nr. 1107/2009... (PDF). This approval expired in August 2013.
In European countries such as Germany and Austria, as well as Switzerland, no plant protection products containing this active substance are approved.Generaldirektion Gesundheit und Lebensmittelsicherheit der Europäischen Kommission: Eintrag zu Bitertanol in der EU-Pestiziddatenbank; Eintrag in den nationalen Pflanzenschutzmittelverzeichnissen der Schweiz, Österreichs und Deutschlands, abgerufen am 13. August 2025.
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