NMR Assignments and Conformational Studies of New C′3-Cyclotriveratrylenes with Pendant Thiol Substituents

✍ Scribed by Catherine Bougault; Jeanne Jordanov; Michel Bardet

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 883 KB
• Volume: 34
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199601)34:1<24::aid-omr836>3.0.co;2-7

✦ Synopsis

H and 13C NMR spectra of two new C,-cyclotriveratrylenic trithiols were fully assigned, and their conformation in solution was probed by the analysis of T, and NOE quantitative measurements, NOESY experiments and force-field calculations. The validity of this analysis was first tested on an aliphatic trithiol 1, for which an x-ray crystal structure was also available, and then applied to investigate an aromatic trithiol 2. The tribenzylic ring of both molecules retains in solution the rigid bowl-like shape determined by x-ray analysis. In the case of 1, with three -OCH2CH2CH2SH groups as side-arms, no preferential conformation was found, which indicates that the thiol arms are very mobile in solution. In 2, where the side-arms are made up by three -OCH,-m-C,H,SH groups, the preferential orientation of the thiophenol rings is perpendicular to the tribenzylenic bowl, with the SH groups pointing towards either the inside or the outside of the cavity.