L-Pyroglutamic Acid → tert-Butyl 5-oxo-L-prolinate

참여 물질

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To a suspension of L-pyroglutamic acid (13.2 g, 102 mmol) in t-butyl acetate (200 mL), was added perchloric acid (70%, 9.7 mL, 113 mmol). The mixture was stirred at rt for 20 h, then poured into sat. NaHCO3. NaHCO3 (s) was added until neutral. The aqueous phase was extracted with EtOAc (6×). The combined organic extract was dried (Na2SO4) and concentrated to afford 13.68 g (72%) of the title compound, 1a. 1H NMR (300 MHz, CDCl3) δ 6.17 (br s, 1H), 4.13 (dd, J=7.4, 5.2, 1H), 2.44–2.31 (m, 3H), 2.22–2.15 (m, 1H), 1.47 (s, 9H).

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