Studies on isocyanides. A facile synthesis of 4,5-dihydro-1,4-benzothiazepin-3(2H)-ones via post-condensation modifications of the Ugi reaction

A series of 4,5-dihydro-1,4-benzothiazepin-3(2H)-ones 9 was prepared via Ugi 4-CC, SN aliph, and SN arom. This procedure, which resembles the well-known Hulme’s and Zhu’s protocols, allows a facile access to the above heterocyclic system. Further transformations of the cyclized products appear to be feasible.