Acetic Anhydride → 4-{(3S)-3-[(tert-Butoxycarbonyl)amino]piperidin-1-yl}-3-nitro-6,7-dihydro-5H-cyclopenta[b]pyridin-7-yl acetate

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Reaction Conditions

Reaction Steps

A mixture of Ac2O (0.90 g, 8.8 mmol) and tert-butyl [(3S)-1-(3-nitro-1-oxido-6,7-dihydro-5H-cyclopenta[b]pyridin-4-yl)piperidin-3-yl]carbamate (270 mg, 0.714 mmol) was sealed and heated at 90° C. for 1 h, then allowed to cool to room temperature. The excess Ac2O was removed under reduced pressure. The residue was dissolved in DCM, and then poured into ice cold aq. Na2CO3. The mixture was extracted with DCM twice. The combined extracts were dried, filtered and concentrated under reduced pressure to give a crude product, which was purified by preparative LC-MS (XBridge™ preparative C18 5 μm 30×10 mm OBD™ column, flow rate 60 mL/min., eluting with a gradient of MeCN and water with 0.15% NH4OH) to provide the sub-title compound as a yellow powder (65 mg, 22%). LCMS calc. for C20H29N4O6 (M+H)+: m/z=421.2. Found: 421.3.

Provenance & Evidence