1369964-25-9Relevant academic research and scientific papers
Sequential Synthesis of Organosilicon-Linked 2-Methoxypyridines by Non-Cryogenic ortho-Metallation Using the nBu2TMPMg·Li Reagent and Hydrosilylation
Struk, ?ukasz,Sos?nicki, Jacek G.,Idzik, Tomasz J.,Maciejewska, Gabriela
, p. 1292 - 1304 (2016)
The non-cryogenic synthesis of 5/6- and/or 3-silyl-functionalised 2-methoxypyridines by a 5-Br/Mg exchange process using nBu2iPrMg Li and LiCl and involving C-3 metallation using a novel nBu2TMPMg Li reagent is described. Furthermore, the usefulness of nBu2TMPMg Li in the functionalisation of 2-methoxypyridine at the 3-position with a wide range of electrophiles was successfully tested. The above achievements have allowed the construction of organosilicon-linked 2-methoxypyridines composed of two, three and four rings by the hydrosilylation of 5- and/or 3-SiH(or alkenyl) derivatives using the hitherto rarely applied [Pt(cod)Me2] catalyst. Additionally, the synthesis of a one-chain oligomer consisting of eight 2-methoxypyridines obtained by the hydrosilylation/polymerisation approach, followed by protodesilylation of the SiHMe2 group was also achieved by manipulating the amount of catalyst in the reactions.
Deprotonative metalation of aromatic compounds using mixed lithium-iron combinations
Nagaradja, Elisabeth,Chevallier, Floris,Roisnel, Thierry,Jouikov, Viatcheslav,Mongin, Florence
experimental part, p. 3063 - 3073 (2012/06/01)
The deprotonation of 2-methoxypyridine was attempted using putative (TMP)3FeLi prepared from different iron sources. Using iodine to intercept the metalated 2-methoxypyridine, the best result was obtained from FeBr2 (1 equiv) using THF at room temperature; nevertheless, in addition to the expected iodide, the corresponding 2,2′-dimer was obtained (86% total yield). The origin of the competitive formation of the 2,2′-dimer was not identified but mechanisms were suggested to explain its formation. It was observed that the nature of the electrophile employed to trap the 3-metalated 2-methoxypyridine has a strong impact on this dimer formation, the latter being favored using iodine (35% yield), but also benzophenone (28%), benzoyl chloride (22%), methyl iodide (27%), allyl bromide (15%), benzyl bromide (41%), and tetramethylthiuram disulphide (36%); for this reason, the yields of the expected derivatives were only 51, 15, 62, 0, 5, 18, and 0%, respectively. In contrast, using aldehydes readily led to the expected pyridine alcohols without dimerization (59% yield using 3,4,5-trimethoxybenzaldehyde and 66% yield using pivalaldehyde). 2,6-Dimethoxypyridine (in 68% yield), anisole (47%), 2,4-dimethoxypyrimidine (50% at C5 and 3% at C6), 2-fluoropyridine (64%), and thiophene (49%) were similarly converted into the corresponding alcohols after subsequent trapping with pivalaldehyde. Using iodine to trap the 2-metalated anisole did not lead to dimer formation, and 2-iodoanisole was isolated in 71% yield.
