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http://hdl.handle.net/10773/19179
Title: | Lithiation of N,N,N ',N '-tetraisopropylpyridine-2,6-dicarboxamide: synthesis, characterization and single crystal X-ray studies of chalcogen (Se/Te) derivatives of N,N,N ',N '-tetraisopropylpyridine-2,6-dicarboxamide |
Author: | Dhau, Jaspreet S. Dhir, Rupy Singh, Avtar Singh, Amritpal Brandao, Paula Felix, Vitor |
Keywords: | CENTER-DOT-N CONVENIENT SYNTHESIS HALOGEN-DANCE SE CHEMISTRY DISELENIDE ARYL |
Issue Date: | 2014 |
Publisher: | PERGAMON-ELSEVIER SCIENCE LTD |
Abstract: | The lithiation of N,N,N',N'-tetraisopropylpyridine-2,6-dicarboxamide (1) and its application in the synthesis of chalcogen (Se/Te) derivatives was investigated. It was found that the selectivity of the reaction changed with the change in the amount of n-BuLi used. The lithiation of 1 with 6.1 equiv of n-BuLi followed by subsequent reactions with selenium/tellurium and iodomethane exclusively afforded the monosubstituted chalcogen derivative (2a/2b) in excellent yield. However, the use of 2.1 or 4.2 equiv of n-BuLi gave two additional products along with 2a/2b. One of the isolated products corresponded to the double lithiation of 1 and the other to the ortho lithiation followed by nucleophilic addition of n-BuLi to the one of the two carbonyl moieties. The prepared compounds have been characterized by single crystal X-ray crystallography, NMR (H-1, C-13, Se-77 and Te-125), IR, UV-Visible and Mass spectroscopy. Crystal structure of N,N,N',N'-tetraisopropyl-3,5-bis(methyltelluryl)pyridine-2,6-dicarboxamide (3b) reveals a strong intramolecular C center dot O center dot center dot center dot Te secondary and intermolecular Te center dot center dot center dot pi pyridyl interactions. (C) 2014 Elsevier Ltd. All rights reserved. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/19179 |
DOI: | 10.1016/j.tet.2014.05.066 |
ISSN: | 0040-4020 |
Publisher Version: | 10.1016/j.tet.2014.05.066 |
Appears in Collections: | CICECO - Artigos |
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