Back in 1994, we published the crystal structure of the molecule below (X=H), a putative anti-malarial drug called halofantrine . Little did we realise that a whole area of organo catalysis based on a thiourea catalyst with a similar motif would emerge a little later. Here is how the two are connected. In our original article we described how our interest was sparked by observing the following chiral HPLC behaviour.