Catalytic Synthesis of 7-Alkoxylcoumarins by TBAB

Ten novel 7-alkoxylcoumarins were synthesized by Williamson reaction of 7-hydroxycoumarin(1) or 7-hydroxy-4-methylcoumarin(2) and five alkyl halides using tetrabutylammonium bromide(TBAB) as a phase transfer catalyst. The structures were characterized by 1H NMR, IR and MS. Optimum conditions of Williamson reaction in acetone in presence of KI at 60 ℃~80 ℃ for 5 h~8 h were as follows: 1(or 2) was 5 mmol; n(1 or 2) ∶n(alkyl halide) ∶n(K2CO3) ∶n(TBAB)=1.0 ∶1.5 ∶2.5 ∶0.1. The yields were 84%~96% under the optimum conditions.