A facile and scaleable synthesis of a potent and selective histamine H3 receptor antagonist, ABT-239 (1), was developed starting from commercially available 4'-hydroxy-biphenyl-4- carbonitrile (2). The synthesis comprised four chemical steps and a salt formation step with an overall yield of 40%. A highly selective monoiodination of a phenol was developed and used to prepare iodophenol (3b) in near quantitative yield using NIS in AcOH in the ...