GENERAL METHODS: Benzyl chloroformate (1 mmol) was slowly added to morpholine (1 mmol), followed by microwave radiation (100 W) of the mixture, with reaction times referring to Tables 2, 3, 4, and 5.The progress of the reaction was monitored by Thin Layer Chromatography (TLC), with the unfolding agent ratio of dichloromethane: methanol (98:2). Upon completion of the reaction, n-hexane (15-20 mL) was added to the reaction mixture and allowed to stand overnight at room temperature. The solid product was collected by filtration, washed with hexane and dried to give benzyl morpholine-4-carboxylate in good to excellent yield. The successful protection of the amine structure was confirmed by the generation of hydrogen chloride gas during the reaction.
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