organic compounds
Open access
The title compound, C21H26NO4+·Br−, also known as R-methylnaltrexone (MNTX) bromide, is a selective peripherally acting μ-opioid receptor antagonist with a oroxymorphone skeleton, synthesized by hydroxyl protection, N-methylation, deprotection and anion exchange of naltrexone. It comprises a five-ring system A/B/C/D/E. Rings C and E adopt distorted chair conformations, whereas ring D is in half-chair conformation. The C/E ring junctions are trans fused. The dihedral angle between rings D and E is 82.3 (1)°, while the dihedral angles between the planes of rings C and A, and rings D and E are respectively 81.7 (1), 75.9 (1) and 12.2 (1)°. In the crystal, molecules are linked by O—HBr hydrogen bonds.
organic compounds
Open access
The title compound, C46H24F12O8·C4H8O, consists of a cyclic aryl ester dimer and a tetrahydrofuran molecule. In the structure of the cyclic dimer, one carbonyl group stretches above the cavity and the other below.