Crystal and molecular structure of the histamine H2-receptor antagonist N-(4-imidazol-4-ylbutyl)-N′-methylthiourea (burimamide)

Abstract

The crystal and molecular structure of the title compound has been determined from three-dimensional X-ray diffractometer data by Patterson and Fourier methods. Crystals are orthorhombic, space group Pccn, Z= 8, a= 10·71 ± 0·01, b= 22·84 ± 0·02, c= 9·51 ± 0·01 Å. Data were refined by least-squares methods to R 4·8% for 1507 independent reflections. The crystals are built up from isolated molecules linked together by hydrogen bonds between imidazole rings and thiourea residues. The molecular conformation may be described in terms of three planes, those of the imidazole ring, alkyl chain, and thiourea residue. The imidazole and thiourea planes make angles of 83·6 and –109·5° respectively with the plane of the alkyl chain. There are no imidazole–thiourea contacts. The overall configuration is determined by a combination of intramolecular repulsion and crystal-packing factors.