Methylation of Phenolic Hydroxyl Group and Demethylation of Anisoles

Abstract

A mild methylation of phenolic hydroxyl groups with iodomethane was enabled in the presence of sodium bis(trimethylsilyl)amide at room temperature. The reverse reaction, namely demethylation of methyl phenyl ethers, was easily achieved by microwave heating with neat iodotrimethylsilane.

A Concise and Flexible Synthesis of C2′-Sulfonylated Quinine Derivatives

“…To improve the efficiency of the demethylation of 10, a further screen of the reaction parameters was carried out. Based on the literature, several different methods, including the use of LiCl, 15 LiI, 16 TMSI 17,18 (TMS = trimethylsilyl), BCl 3 , 19 the ionic liquid (Me 3 NH) + (Al 2 Cl 7 ) -, 20 BBr 3 /catechol, 21 AlCl 3 , 22 and AlCl 3 /EtSH 23 were briefly examined. The results showed that while other methods gave complex mixtures with low yields, the combination of AlCl 3 (5.0 equiv) and EtSH (5.0 equiv) in DCM at 0 °C afforded 6 in 76% isolated yield.…”