Synthesis, X-ray powder diffraction and DFT calculations of vasorelaxant active 3-(arylmethylidene)pyrrolidine-2,5-diones

Abstract

Two 3-(arylmethylidene)pyrrolidine-2,5-diones, 12a and 12b, were synthesized and characterized by powder X-ray diffraction utilizing a high-resolution synchrotron X-ray powder technique. The basic difference between the theoretical (AM1, PM3 and DFT computational studies) and experimental (X-ray diffraction) structures is the relative orientation of aryl groups attached to the pyrrolidinyl nitrogen and exocyclic olefinic linkage. The lattice form controlling the X-ray structure is responsible for these observations. Pyrrolidines 12a, b reveal vasodilation bio-properties with potency higher than that of doxazosin (clinically applicable α₁-adrenergic receptor blocker).