A novel approach for the synthesis of the peripheral benzodiazepine receptor ligand, PK11195

A new synthesis of the peripheral benzodiazepine receptor ligand, PK11195 has been developed in only six-steps using a Heck-type reaction and a Suzuki coupling to effect the key transformations. The flexibility of this new approach is demonstrated by the synthesis of an iodo-analogue of PK11195 prepared from the corresponding bromide using a copper catalysed aromatic Finkelstein reaction.