Selective Catalytic Methylation of Phloroglucinol with Dimethyl Carbonate in the Presence of Heterogeneous Acids

摘要

A facile process for the methylation of phloroglucinol using environmentally friendly dimethyl carbonate as methylating agent and solvent is described. Widely available and inexpensive solid acids have been used as catalysts to promote this transformation. H-Y zeolite proved particularly selective for monomethylation, hence it has been used for the convenient preparation of methoxyresorcinol (MR), with only limited coproduction of dimethoxyphenol (DMP). Conversely, the use of tungstosilicic acid on silica easily afforded DMP in excellent isolated yield.