Acetic Anhydride → 1-Hydroxy-3(carboxymethyl)-3,4-dihydroanthraquinone

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Reaction Steps

1-hydroxy-3,4-dihydroanthraquinone is reacted with 2 moles of acetic anhydride in pyridine for 15 hours. The mixture is poured into water, when 1-acetyl-3,4-dihydro-anthraquinone separates. It is collected, washed and dried at 80° C. and 2 Pa absolute (15 torr). The 1-acetyl-3,4-dihydroanthraquinone is reacted with 2 moles of N-bromosuccinimide while suspended in boiling carbon tetrachloride under reflux for 2 hours. 1-acetyl-3-bromo-3,4-dihydroanthraquinone is collected, dissolved in acetone and treated with ethyl 2-bromoacetate and excess copper powder, under reflux, for 2 hours. The ethyl ester of 1-acetoxy-3(carboxymethyl)-3,4-dihydroanthraquinone is collected and hydrolysed by standing overnight in N sodium hydroxide solution under nitrogen. The free acid, 1-hydroxy-3(carboxymethyl)-3,4-dihydroanthraquinone is then obtained on acidification.

Provenance & Evidence