Calix 6 arene derivatives selectively functionalized at alternate sites on the smaller rim with 2-phenylpyridine and 2-fluorenylpyridine substituents to provide deep cavities

Zeng, X.S.; Batsanov, A.S.; Bryce, M.R.

Abstract

The synthesis is described of calix[6]arene derivatives 4, 9, and 14 functionalized at alternate sites on the smaller rim with 4‘-(pyrid-2‘ ‘-yl)phenylmethoxy, (6‘-phenylpyrid-3‘-ylmethoxy), and {6‘-[2-(9,9-di-n-hexylfluorenyl)]pyrid-3‘-ylmethoxy} substituents, respectively. They were obtained by 3-fold reactions of 2-[4-(bromomethyl)phenyl]pyridine (3), 5-(bromomethyl)-2-phenylpyridine (8), and 5-(bromomethyl)-2-(9,9-di-n-hexylfluorenyl)pyridine (13) with the 1,3,5-trimethylether of the t-Bu-calix[6]arene in the presence of sodium hydride in THF in 56−75% yields. Detailed analysis of the 1H NMR spectra (including variable-temperature data for 4) has established that 4, 9, and 14 exist predominantly in the C3v cone conformation with minor Cs isomers also observed. The X-ray crystal structure of 4 reveals two molecules of similar cone conformation, with all three 4‘-(pyrid-2‘ ‘-yl)phenylmethoxy substituents stretched in the axial direction. Molecule I has a dimeric capsule structure with (pyrid-2‘ ‘-yl)phenylmethoxy substituents of one molecule interpenetrating those of its inversion equivalent to form a deep enclosed intermolecular cavity, which contains a CH2Cl2 guest molecule. Molecule II forms no such pair:  the intramolecular cavity is filled with solvent molecules.

Citation

Zeng, X., Batsanov, A., & Bryce, M. (2006). Calix 6 arene derivatives selectively functionalized at alternate sites on the smaller rim with 2-phenylpyridine and 2-fluorenylpyridine substituents to provide deep cavities. Journal of Organic Chemistry, 71(26), 9589-9594. https://doi.org/10.1021/jo0614341

• Journal Article Type: Article
• Publication Date: 2006-12
• Journal: Journal of Organic Chemistry
• Print ISSN: 0022-3263
• Electronic ISSN: 1520-6904
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 71
• Issue: 26
• Pages: 9589-9594
• DOI: https://doi.org/10.1021/jo0614341