azoxystrobin

{{chembox |ImageFile = Azoxystrobin colour.svg |ImageFile1 = Azoxystrobin-from-xtal-3D-balls.png |PIN = Methyl (2E)-2-(2-{[6-(2-cyanophenoxy)pyrimidin-4-yl]oxy}phenyl)-3-methoxyprop-2-enoate |OtherNames = Azoxystrobine, ICIA5504 |Section1 = |Section2= |Section3= }} Azoxystrobin is a broad spectrum systemic fungicide widely used in agriculture to protect crops from fungal diseases. It was first marketed in 1996 using the brand name Amistar and by 1999 it had been registered in 48 countries on more than 50 crops. In the year 2000 it was announced that it had been granted UK Millennium product status.

== History == thumb|left |700px |EEE (incorrect first published structure) and EZE strobilurin A with the related natural product fungicide oudemansin A thumb|Strobilurus tenacellus In 1977, academic research groups in Germany published details of two new antifungal antibiotics they had isolated from the basidiomycete fungus Strobilurus tenacellus. They named these strobilurin A and B but did not provide detailed structures, only data based on their high-resolution mass spectra, which showed that the simpler of the two had molecular formula C16H18O3. In the following year, further details including structures were published and a related fungicide, oudemansin A from the fungus Oudemansiella mucida, whose identity had been determined by X-ray crystallography, was disclosed. When the fungicidal effects were shown to stem from what was then a novel mode of action, chemists at the Imperial Chemical Industries (ICI) research site at Jealott's Hill became interested to use them as leads to develop new fungicides suitable for use in agriculture. The first task was to synthesize a sample of strobilurin A for testing. In doing so, it was discovered that the structure that had been published was incorrect in the stereochemistry of one of the double bonds: the strobilurins, in fact, have the E,Z,E not E,E,E configuration. Once this was realised and the correct material was made and tested it was shown, as expected, to be active in vitro but insufficiently stable to light to be active in the glasshouse. A large programme of chemistry to make analogues was begun when it was discovered that a new stilbene structure containing the β-methoxyacrylate portion (shown in blue and believed to be the toxophore) had good activity in glasshouse tests but still lacked sufficient photostability. After more than 1400 analogues had been made and tested the team chose azoxystrobin for commercialisation and it was developed under the code number ICIA5504. thumb |centre |600px |The (E)-Stilbene|stilbene was the first synthetic analogue to show activity and led to azoxystrobin First sales were in 1996 using the brand name Amistar: it then gained fast-track registration in the United States, where it was marketed in 1997 as Heritage. By 1999 it had been registered in 48 countries on more than 50 crops. In the year 2000 it was announced that it had been granted Millennium product status by the UK Prime Minister, Tony Blair, as it had become in three years the world's best-selling fungicide. Meanwhile, BASF scientists who were collaborating with the German academic groups that had discovered strobilurin A had independently invented kresoxim-methyl, which was also launched in 1996.