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.