Acetic Anhydride → 3-[2-(2-Methoxyphenyl)-ethyl]-2,4-dioxo-3,9-diaza-bicyclo[3.3.1]nonane-9-carboxylic Acid Benzyl Ester

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Reaction Steps

2,4-Dioxo-3-oxa-9-aza-bicyclo[3.3.1]nonane-9-carboxylic acid benzyl ester (Compound 2, 1.00 g, 3.45 mmol), which was prepared from Compound 1, was dissolved in dioxane (1 mL), and 2-methoxyphenethylamine (0.50 mL, 3.45 mmol) was added from the top. The mixture was stirred at room temperature for 1 hour. After this time, acetic anhydride (0.65 mL, 6.9 mmol) was added, and the reaction was refluxed for 5 hours. Flash chromatographic purification of the residue (20% EtOAc/hexanes) gave Compound 8 (1.23 g, 90% yield) as a clear oil. Rf=0.75 (50% EtOAc/hexanes), 0.66; 1H NMR: δ 1.75-2.05 (m, 6H), 2.84-2.89 (m, 2H), 3.83 (s, 3H), 4.04-4.10 (m, 2H), 4.90 (brs, 2H), 5.16 (s, 2H), 6.78-6.83 (m, 2H), 7.05 (dd, 1H, J=7.5, 1.6), 7.13-7.20 (m, 1H), 7.33-7.41 (m, 5H).

Provenance & Evidence