1H and 13C NMR assignments and X-ray structures for three monocyclic benzoannelated dilactam polyethers

✍ Scribed by Gary L. N. Smith; Susan S. Alguindigue; Masood A. Khan; Douglas R. Powell; Richard W. Taylor

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 298 KB
• Volume: 44
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1868

✦ Synopsis

Abstract

Three monocyclic polyether dilactams, 17,18‐dihydro‐5__H__, 9__H__‐dibenzo[e,n]1,4,10,7,13trioxadiazacyclopentadecine‐6,10(7__H__,11__H__)‐dione (1); 9,10,20,21‐tetrahydro‐5__H__, 12__H__‐dibenzo[e,q]1,4,10,13,7,16tetraoxadiazacyclooctadecine‐6, 13(7__H__,14__H__)‐dione (2); and 6,7,9,10‐tetrahydro‐16__H__, 20__H__‐dibenzo[h,q]1,4,7,13, 10,16tetraoxadiazacyclooctadecine‐17, 21(18__H__,22__H__)‐dione (3) were isolated during the synthesis of several benzoannelated cryptands. The complete assignments of the ^1^H and ^13^C NMR spectra of 1, 2 and 3 in CDCl~3~ were made using gCOSY, gHMBC, gHMQC, HMQC, HSQC, and NOESY 1D techniques. The ortho (H2) benzene protons show significant downfield shifts (1.16–1.43 ppm) that are consistent with an exodentate orientation for the amide carbonyl groups. The X‐ray crystal structures of 1, 2 and 3 show that the carbonyl groups adopt an exodentate conformation in the solid state. Copyright © 2006 John Wiley & Sons, Ltd.