Citric Acid → 2-{1-[(Tert-butoxy)carbonyl]piperidin-4-yl}-1,3-oxazole-4-carboxylic acid

関与物質

反応条件

反応手順

1,1-Dimethylethyl 4-[4-(methoxycarbonyl)-2-oxazolyl]-1-piperidinecarboxylate (i.e. the product of Example 7, Step C) (1.41 g, 4.55 mmol) was dissolved in 12 mL tetrahydrofuran, and 8 mL of water was added. The reaction mixture was cooled to 0° C. with vigorous stirring. A 1 N aqueous sodium hydroxide solution (9.1 mL) was added dropwise, and the reaction mixture was stirred at room temperature for 2 h. The mixture was diluted with saturated sodium chloride solution (10 mL), 30 mL of diethyl ether was added and the aqueous phase was acidified to pH 3-4 by dropwise addition of 20% citric acid solution. The precipitated solid was filtered and dried to give 1.21 g of the title compound.

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