title: Spectroscopic characterization and molecular structure of 3,14-dimethyl-2,6,13,17-tetraazapentacyclo[16.4.0.1(2,17).1(6,13).0(7,12)]tetracosane.
abstract: Constrained cyclam derivatives have been found to exhibit anti-HIV effects. The strength of binding to the CXCR4 receptor correlates with anti-HIV activity. The conformation of the macrocyclic compound is very important for co-receptor recognition. Therefore, knowledge of the conformation and crystal packing of macrocycles has become important in developing new highly effective anti-HIV drugs. Structural modifications of N-functionalized polyaza macrocyclic compounds have been achieved using various methods. A new synthesis affording single crystals of the title tetraazapentacyclo[16.4.0.1(2,17).1(6,13).0(7,12)]tetracosane macrocycle, C22H40N4, is reported. Formaldehyde reacts readily at room temperature with the tetraazatricyclo[16.4.0.0(2,17)]docosane precursor to yield a macropolycycle containing two five-membered rings. Characterization by elemental, spectroscopic and single-crystal X-ray diffraction analyses shows that the asymmetric unit contains half of a centrosymmetric molecule. The molecular structure shows a trans conformation for the two methylene bridges owing to molecular symmetry. The crystal structure is stabilized by intramolecular C-H...N hydrogen bonds. NMR and IR spectroscopic properties support the methylene-bridged macrocyclic structure.
authors: Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea.
authors: Dohyun
authors: D
authors: Moon
authors: Department of Chemistry, Andong National University, Andong 36729, Republic of Korea.
authors: Yong Pyo
authors: YP
authors: Hong
authors: Department of Chemistry, Andong National University, Andong 36729, Republic of Korea.
authors: Jong Ha
authors: JH
authors: Choi
keywords: anti conformation; anti-HIV drug; crystal structure; molecular structure; pentacyclotetracosane; physical properties; spectroscopic analysis; synchrotron radiation; tetraaza macrocycle