Synthesis of a Human Urate Transporter-1 Inhibitor, an Arginine Vasopressin Antagonist, and a 17β-Hydroxysteroid Dehydrogenase Type-3 Inhibitor, Using Ring-Expansion of Cyclic Ketoximes with DIBALH

Synthesis of three clinical candidates for medicines, a human urate transporter-1 inhibitor, an arginine vasopressin antagonist, and a 17 beta-hydroxysteroid dehydrogenase type-3 inhibitor, is described. These compounds were synthesized via construction of their 3,4-dihydro-2H-benzo[b][1,4]oxazine, dibenzodiazepine, and dibenzazocine skeletons, respectively, using the reductive ring-expansion reaction of the corresponding bicyclic or tricyclic oximes with diisobutylaluminum hydride.