Lovely Cyclization for a Multipurpose Drug: Clonidine
This is not the most exciting synthesis ever, although what I describe here is a quick method to yield a very interesting drug: clonidine. A drug which, despite its age, hasn't lost its touch. Oh no, not at all.
Clonidine is an alpha-2 agonist used in the treatment of hypertension. Nowadays, however, this molecule is mainly used for a large spectrum of purposes: from helping former opiate consumers to cope with withdrawals, to the therapy against insomnia, ADHD (Attention-deficit hyperactivity disorders) and other neuropathologies. Some doctors prescribe clonidine for reducing hot flushes during menopause too.
Not to mention the many other clinical contexts where clonidine may find a place in the future, looking at the number of ongoing tests.
Going back to the chemical aspects, my favourite step is the intramolecular cyclization after the reaction with ethanediamine. I mean, it's the kind of thing that makes me think: "Well, in the end, organic synthesis is not that difficult: your adduct does everything." 
Ammonium thiocyanate provides, in the end, a good leaving group.
The two chlorine groups on the benzene guarantee a high activity, not only due to electronic effects, but, thanks to steric hindrance, because they perfectly block the aromatic ring orthogonally to the imidazoline: this is the active conformation, so, in terms of activity, Cl>Br>CF3>>F.
