Acetic Anhydride → 5-Acetylamino-1-hydroxy-5,6,7,8-tetrahydro-naphthalene

Participants

Reaction Conditions

Reaction Steps

50 mmol of 5-amino-1-hydroxy-5,6,7,8-tetrahydronaphthalene are stirred in a solution of 200 mmol of acetic anhydride and 200 mmol of triethylamine, to which a spatula-tip of dimethylaminopyridine has been added, for 2 hours. The mixture is filtered, the residue is rinsed thoroughly with tetrahydrofuran and the filtrate is evaporated. The residue is taken up in ethyl acetate and the mixture is washed with 1N HCl, saturated NaHCO3, 1N HCl, saturated NaHCO3 and saturated NaCl solution, dried over Na2SO4 and evaporated. The bis-acetate which remains is dissolved in 100 ml of MeOH and the solution is then added dropwise to 100 ml of 1N KOH at room temperature. The mixture is stirred at an internal temperature of 50° C. for 2 hours and acidified with concentrated HCl and the MeOH is stripped off. The acid aqueous phase is extracted by shaking 2 to 3 times with ethyl acetate and the combined organic phases are dried with Na2SO4 and evaporated. The residue is recrystallized from ethyl acetate.

Provenance & Evidence