Fig 3.

Chemical structures of novel kainate derivatives – the ZCZ compounds. The upper panel shows the original structure of kainate. The middle row shows kainate derivative compounds, each functionalised by the addition of a side-group at carbon 3 to make it amenable to ‘click-chemistry’. To achieve this, each required to be synthesised from different simpler constituents to arrive at the final structure illustrated, each synthesis requiring different low-yield and complex intermediates and chemical reactions. Only ZCZ90 retained its activity (Fig.4). The lower row shows further development of the triazole derivative ZCZ90 to add either a fluorescein (ZCZ172) or biotin (ZCZ180) side-chain directly to the compound by click-chemistry. The fact that both compounds started directly from ZCZ90 as the initial component, and not its constituent parts, indicates the great utility of this technique.