Triethylamine → 3-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]-7-tert-butyl-5-methyl-3H-benzofuran-2-one

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Reaction Steps

A solution of 5.5 g (25.0 mmol) of 7-tert-butyl-3-hydroxy-5-methyl-3H-benzofuran-2-one (compound (102), Example 2), and 3.9 ml (28.0 mmol) of triethylamine in 30 ml of dichloromethane is added dropwise to a solution of 8.32 g (28.0 mmol) of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl chloride (prepared from 7.8 g (28.0 mmol) of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and thionyl chloride) in 10 ml of dichloromethane. The reaction mixture is then refluxed for 1 hour, then cooled and washed with water and 5% aqueous sodium hydrogencarbonate solution. The organic phases are combined, dried over magnesium sulfate and concentrated on a vacuum rotary evaporator. Three crystallisations of the residue from acetonitrile yield 4.6 g (38%) of 3-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]-7-tert-butyl-5 -methyl-3H-benzofuran-2-one, m.p. 151°-154° C. (compound (113), Table 1).

Provenance & Evidence