The Crystal and Molecular Structure of 2-(Benzothiazol-2-yl)-3-[2-ethoxycarbonyl-1-(ethoxycarbonylmethyl)pyrrol-4-yl]propenenitrile

The crystal and molecular structure of the title compound, C21H19N3O4S, which belongs to a broad class of nitrogen heterocycles widely used in medicinal chemistry as well as the pharmaceutical and chemical industries, was determined in order to elucidate the conformation of the substituents bonded to the pyrrole ring and the extent of π-electron delocalization. The compound crystallizes in the monoclinic space group C2/c with a = 30.266(7) A, b = 9.403(6) A, c = 15.881(9) A , β = 120.35(6)o, and Z = 8. The structure was refined by the least-squares procedure to R = 0.049 for 2561 observed reflections. As indicated by the planarity of the molecule and the bond-lengths pattern, the π-electron delocalization extends over the whole molecule except for the ethoxycarbonylmethyl group. As expected, the arrangement of the benzothiazole and pyrrole moieties at the ethylenic double bond is trans.