Dimethylformamide → HCID 117697690, compound

Participants

Reaction Conditions

Reaction Steps

To a suspension of t-BuOK (1.82 g, 16.26 mmol) in toluene (30 mL) was added dimethyl carbonate (0.98 g, 10.84 mmol). The mixture was heated at 90° C. for 5 mins, and then 7-oxo-3-oxa-9-aza-bicyclo[3.3.1]nonane-9-carboxylic acid tert-butyl ester (1.3 g, 5.4 mmol) was added. After the resulting mixture was stirred at 90° C. for 30 mins, the mixture was turned to brown gel, and then DMF (1.5 mL) was added to get a brown solution. The mixture was stirred at 90° C. for 3 hours. After it was cooled to room temperature, silica gel (25 g, 100200 mesh) was added and the solvent was concentrated in vacuo. The residue was purified by flash column chromatography (EtOAc in PE 0%˜70%) to give 7-oxo-3-oxa-9-aza-bicyclo[3.3.1]nonane-6,9-dicarboxylic acid 9-tert-butyl ester 6-methyl ester (Compound AO) as light yellow oil (0.8 g, 49%). LC/MS: calc'd 300 (MH+), exp 300 (MH+); 1HNMR (400 MHz, CDCl3) δ 1.40-1.45 (m, 9H), 2.29-2.41 (m, 1H), 2.68-2.84 (m, 1H), 3.47-3.79 (m, 7H), 3.88-3.96 (m, 0.5H), 4.09-4.16 (m, 0.3H), 4.30-4.45 (m, 1H), 4.55-4.67 (m, 0.8H), 11.86 (s, 0.3H).

Provenance & Evidence