Acetic Acid → HCID 178452458, Verbindung

Beteiligte Stoffe

Reaktionsschritte

To a solution of compound 24A (930 mg, 3.0 mmol) and (S)-morpholine-3,4-dicarboxylic acid 4-tert-butyl ester (19A, 2.09 g, 9.0 mmol) in anhydrous dichloromethane (20 mL) was added N,N′-diisopropylcarbodiimide (DIPC, 1.4 mL, 9.0 mmol). The reaction mixture was stirred at rt overnight. Solvent was removed. To the residua were added THF (20 mL) and methanol (20 mL) and a solution of LiOH.H2O (1.0 g, 23.84 mmol) in water (10 mL). The mixture was stirred at rt for 2 h. It was then neutralized with acetic acid (1.36 mL, 23.84 mmol). The mixture was diluted with ethyl acetate (˜100 mL), washed with brine, and dried over sodium sulfate. It was filtered, concentrated and filtered again to remove diisopropylurea. The filtrate was purified with silica column chromatography eluting with dichloromethane/ethyl acetate (v/v 5/1, 3/1, 2/1, 1/1) to provide the title compound (28A, 1.12 g) as a yellowish solid in 71.3% yield. LCMS (ESI) m/z 587.15 (MNa+), 521.05 (MH+), 421.06; HPLC: tR=5.32 min.

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