Hydrochloric Acid → 3-[4-(2-Acetoxyethoxy)phenyl]-5,7-di-tert-butylbenzofuran-2-one

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A suspension of 154.7 g (0.75 mol) of 2,4-di-tert-butylphenol and 106.1 g (0.50 mol) of 4-(2-hydroxyethoxy)mandelic acid (compound (201), Example 10, Table 2) in 200 ml of acetic acid saturated with hydrogen chloride gas stirred under a nitrogen atmosphere is refluxed for 8 hours. The acetic acid is then distilled off on a vacuum rotary evaporator, 15 ml (0.21 mol) of acetyl chloride are added to the residue, and the mixture is maintained at 120° C. for 20 minutes. The reaction mixture is again concentrated on a vacuum rotary evaporator, 400 ml of methanol are added to the residue, and the mixture is allowed to stand at about -8° C. The precipitated crystals are filtered off, washed with 250 ml of cold methanol and dried to give 176.3 g (83%) of 3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butylbenzofuran -2-one, m.p. 93°-96° C. (compound (101), Table 1). Recrystallization from ligroin yields the compound (101) in two crystal forms. Crystal form A: m.p. 75°-78° C., enthalpy of fusion 62.4 Joule/g. Crystal form B: m.p. 93°-96° C., enthalpy of fusion 118.2 Joule/g.

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