Bicyclo[2.2.1]heptane-1-methanesulfonic acid, 7,7-dimethyl-2-oxo-, (1S)- → N-Hydroxy-5-(benzenesulfonylamino)pentanamide

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Reaction Steps

To a solution of 42 (500 mg, 1.95 mmol) in DMF (20 mL) at room temperature were added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, 448 mg, 2.33 mmol), and 1-hydroxybenzotriazole hydrate (HOBT, 395 mg, 2.93 mmol). The mixture was stirred 20 min. at room temperature, and then THPONH2 (342 mg, 2.93 mmol) was added. The resulting mixture was heated at 50° C. for 24 h, and then the DMF solvent was evaporated under reduced pressure and the residue was dissolved in CH2Cl2 and washed with brine and a saturated aqueous solution of NaHCO3. The combined organic extracts were dried over (MgSO4) and then evaporated. The crude compound was purified by flash chromatography using hexane-acetone (1:1) as the solvent mixture. The residue was then dissolved in MeOH (10 mL), and 10-camphorsulfonic acid (CSA, 226 mg, 975 mmol) was added. The mixture was stirred for 2 h at room temperature, and then the solvents were evaporated under reduced pressure at room temperature to avoid thermal decomposition. The crude product was purified by flash chromatography using CH2Cl2/MeOH (9:1) as solvent mixture giving compound 43 as a yellowish oil (259 mg, 48% isolated): 1H NMR: (300 MHz, acetone-d6) δ 9.99 (br. s, 1H), 7.87 (br. s, 2H), 7.62 (br. s), 2.90 (br. s, 2H), 2.05 (br. s, 2H), 1.59-1.49 (m, 4H).

Provenance & Evidence