Crystal structure and anomalous chemical shift of 10-(prop-1-yn-1-yl)-10H-phenothiazine 5,5-dioxide: Intramolecular S⋯N transannular effect
作者:Satoru Umezono、Tsunehisa Okuno
DOI:10.1016/j.molstruc.2013.06.045
日期:2013.10
The novel ynamine compounds, 10-(prop-1-yn-1-yl)-10H-phenothiazine 5-oxide (2) and 10-(prop-1-yn-1-yl)-10H-phenothiazine 5,5-dioxide (3), were prepared by MCPBA oxidation of 10-(prop-1-yn-1-yl)-10H-phenothiazine (1). These compounds were characterized successfully by crystallographical analyses, H-1 and C-13 NMR. The H-1 NMR signals of 2 showed downfield shifts compared with 1 as expected. However two kinds of signals, methyl and 1,9-position of 3, indicated upfield shifts compared with 2. These anomalous upfield shifts were reasonably explained by trans-annular S center dot center dot center dot N interaction and by increase of electron density on the nitrogen atom. (c) 2013 Elsevier B.V. All rights reserved.