Acetic Anhydride → 2,4-Dioxo-3-oxa-9-aza-bicyclo[3.3.1]nonane-9-carboxylic Acid Benzyl Ester

Participants

Reaction Conditions

Reaction Steps

Piperidine-1,2,6-tricarboxylic acid 1-benzyl ester (Compound 1, 19.7 g, 64.11 mmol) was suspended in acetic anhydride (80 mL, 848 mmol) in a dry 250-mL round-bottom flask. The mixture was stirred at 70° C. for 30 minutes until a clear solution formed. The remaining acetic anhydride was removed in vacuo, to afford Compound 2 (18.5 g, 100%) as a clear oil. The material was of sufficiently good quality to be used in the next reaction without purification. The product was sensitive to water, so it was prepared for immediate use in the next step. 1H NMR: δ 1.57-2.01 (cm, 6H), 5.14 (s, 2H), 5.17 (s, 2H), 7.32-7.37 (m, 5H).

Provenance & Evidence