4-Methylmorpholine → (+/-)-6-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-5-oxo-[1,4]diazepane-1-carboxylic acid ethyl ester

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Reaction Steps

To a solution of 150.00 g (208.00 mmol) of N-{2-[(2-amino-ethyl)-ethoxycarbonyl-amino]-1-carboxy-ethyl}-phthalamic acid dissolved in 3 L of anhydrous dimethylformamide was added 75.50 mL (686.40 mmol) of N-methylmorpholine. The resulting mixture was stirred at room temperature for 10 min and 143.00 g (520.00 mmol) of diphenylphosphoryl azide was added. The mixture was stirred at room temperature for 36 h and evaporated to dryness. The mixture was dissolved in dichloromethane, washed with a saturated aqueous solution of ammonium chloride, saturated aqueous solution of sodium chloride, saturated aqueous solution of sodium hydrogen carbonate, dried over sodium sulfate and evaporated to dryness. The residue was chromatographed on silica gel eluting with a mixture of dichloromethane/methanol/aqueous ammonia solution (29%) in the proportions 96/4/0.6 led to afford 23.00 g (33%) of the desired compound.

Provenance & Evidence