Crystallographic studies in the pyrrole series. Part I. Crystal and molecular structure of ethyl 4-acetyl-3-ethyl-5-methylpyrrole-2-carboxylate

Abstract

Crystals of the title compound are monoclinic, space group P2₁/n, Z= 4, with cell dimensions a= 6·772(3), b= 14·628(5), c= 12·187(5)Å, and β= 94·20(12)°. The structure was solved by direct methods, and refined by least-squares to R 0·0615 for the 1531 statistically significant reflections measured. The geometry of the molecule is compared with that observed for the pyrrole ring in other systems; in particular it has been observed that the normal symmetrical bonding arrangement in the ring is here considerably perturbed, owing to the electronic effects of the substituents.