A direct alkylation of resorcinols

Alkylation of resorcinol and methyl-substituted resorcinols and its methyl ethers with alkyl bromides in water and anhydrous organic solvents led to mono- and/or dialkylated resorcinols and alkyl cyclohexendiones, depending on the structure of the starting substrates and reaction conditions. Selective di-alkylation was achieved in both, aqueous and anhydrous conditions, up to 76% yield. Resorcinol monomethyl ethers behaved similarly to phenols, giving in dry organic solvents predominantly ortho -substituted products, and a mixture of ortho- and para-substituted products together with resorcinol ethers in aqueous solution. The alkylation of 2,4,6-trimethyl resorcinol monomethyl ether showed selective 2 C-alkylation in 53% yield. 2-Methyl resorcinol with electrophiles in excess afforded in tetra-alkylation up to 72% yield.