Methanol → Methyl 4-(((2-hydroxyphenethyl)(5-methoxy-5-oxopentyl)amino)methyl)benzoate

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Reaction Conditions

Reaction Steps

A solution of 3.00 g (7.02 mmol) of methyl 4-{[(5-ethoxy-5-oxopentyl)(2-methoxy-phenethyl)amino]methyl}benzoate from Example 1.2 in 60 ml of methylene chloride is cooled to 0° C., and 23.16 ml (23.16 mmol) of a 1N boron tribromide solution in methylene chloride are added dropwise. The solution is stirred at 0° C. for one hour. After addition of 30 ml of dry methanol, the batch is heated at 60° C. for one hour. After cooling, the solvent is removed under reduced pressure and the residue is taken up in a mixture of 57 ml of ethyl acetate and 3 ml of methanol and made alkaline using 10% sodium carbonate solution. The aqueous phase is extracted repeatedly with ethyl acetate/methanol 9/1 and the combined organic phases are washed using saturated sodium chloride solution. After drying over magnesium sulphate and distillative removal of the solvent under reduced pressure, the crude product is purified by flash chromatography over silica gel (0.04-0.063 nm) using the mobile phase cyclohexane/ethyl acetate 2/1.

Provenance & Evidence