Phenyl chloroformate → 4-[2-(Azetidin-1-yl)ethyl]piperazine-1-carboxylic acid [4-(4-nitrophenoxy)pyridin-2-yl]amide

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Reaction Steps

4-(4-Nitrophenoxy)pyridin-2-ylamine (60 mg) was dissolved in tetrahydrofuran (3 ml) under a nitrogen atmosphere. Triethylamine (0.109 ml) and phenyl chloroformate (0.0975 ml) were added thereto while cooling in an ice water bath, followed by warming to room temperature and stirring for 30 min. The reaction mixture was partitioned between ethyl acetate (50 ml) and a saturated aqueous solution of sodium hydrogencarbonate (30 ml). The organic layer was washed with a saturated aqueous solution of sodium hydrogencarbonate (30 ml), water (30 ml), brine (30 ml) in this order, and dried over anhydrous sodium sulfate. The solvent was evaporated to give a residue, to which was then added N-dimethylformamide (3 ml). And then an 1.0 M solution of 1-[2-(azetidin-1-yl)ethyl]piperazine trihydrochloride in methanol (0.884 ml) and triethylamine (0.261 ml) were added thereto, followed by stirring for 4 hrs. The reaction mixture was partitioned between ethyl acetate (50 ml) and a saturated aqueous solution of ammonium chloride (30 ml). The organic layer was washed with a saturated aqueous solution of ammonium chloride (30 ml), water (30 ml), and brine (30 ml), and dried over anhydrous sodium sulfate. The solvent was evaporated to give a residue, which was then purified by silica gel column chromatography (Fuji Silysia NH, ethyl acetate, then ethyl acetate:methanol=9:1). Fractions containing the target compound were concentrated to provide a crude product of the titled compound (122 mg) as a pale yellow solid.

Provenance & Evidence