Microwave-assisted syntheses and crystal structures of benzimidazole thiazolinone derivatives

A rapid and efficient microwave-assisted synthesis method for the preparation of 3-(1H-benzo[d]imidazol-2-yl)-2-substituted phenyl thiazolidin-4-one (4a, 4b) was described. The structures of 4a and 4b were determined by elemental analyses, IR, ¹H NMR and X-ray diffraction. In the crystals of compounds 4a and 4b, the imidazole ring and two benzene rings are planar. Interestingly, the dihedral angle between two benzene rings is 71.5° in 4a, while it is almost perpendicular in 4b due to the different benzene substituents. Meanwhile, the thiazolidinone ring is planar in 4a while slightly distorted with an r.m.s deviation of 0.1494(2) Å in 4b. The hydrogen bonding interactions observed link the molecules to form a dimeric unit, which may be effective in the stabilization of the structure.