The Crystal Structure of Carteolol Hydrochloride : 5-(3-tert-Butylamino-2-hydroxy) propoxy-3, 4-dihydro-2-quinolone, OPC-1085

Abstract

The crystal structure of carteolol hydrochloride (C16H24N2O3·HCl), a novel β-adrenergic blocking agent, was determined by X-ray diffraction analysis. The crystal is monoclinic and the space group is P 21/n with Z=4. The cell dimensions are a=7.873 (4), b=26.435 (19), c=8.549 (7) A, and β=105.67 (6)°. The structure was solved by a direct method using the MULTAN program and refined by a block-diagonal least-squares method to give a final R-value of 0.054. Cl- anion forms two hydrogen bonds with the cationic amino group and one with the hydroxy group. The amino and hydroxy groups are relatively close together, but no intramolecular hydrogen bond is formed. The C (3)-C (4) bond distance of the 3, 4-dihydro-2-quinolone ring, 1.397 A, is rather shorter than a normal single bond distance but it seems probable that the bond is actually single and that the C (3) and C (4) atoms deviate from the least-squares ring plane by 0.42 A and 0.30 A, respectively, to opposite sides.