Synthesis of 5-Hydroxy-4-methoxy-α-methyl-(1,2-benzobutane sultone) from Eugenol and Eugenil Acetate

Abstract

The purpose of this study was to develop an efficient synthesis route to pharmacologically interesting sultone derivatives from readily accessed natural products. Synthetic approach of 5-hydroxy-4-methoxy-α-methyl-(1,2-benzobutane sultone) via eugenol (1) produced only in moderate yield (64 %). On the other hand synthetic approach via eugenil acetate (2) gave 5-hydroxy-4-methoxy-α-methyl-(1,2-benzobutane sultone) in high yield (96 %). Eugenol approach involved only one step reaction due to direct reaction of eugenol with chlorosulfonic acid but in eugenil acetate approach involved two-step reactions due to its preparation of eugenol before reaction with chlorosulfonic acid. Eugenil acetate was prepared smoothly in good yield by esterification of phenolic group of eugenol with acetic anhydride in the presence of sodium bicarbonate. A variety of bicarbonate catalysts such as NaHCO₃, Na₂CO₃ and K₂CO₃ were investigated in O-acetylation of eugenol to afford eugenil acetate (84 %), (72 %) and (88 %), respectively. Structures of all the products have been established by spectral and GC-MS analysis data.