Methyl 10-bromo-9-fluoro-6,7-dihydro-5H-5,7-methanobenzo[c]imidazo[1,2-a]azepine-2-carboxylate → 10-Bromo-9-fluoro-6,7-dihydro-5H-5,7-methanobenzo[c]imidazo[1,2-a]azepine-2-carboxylic acid

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Reaction Steps

Into a 5000-mL 4-necked round-bottom flask was placed a solution of methyl 9-bromo-10-fluoro-2,5-diazatetracyclo[11.1.1.0[2,6].0[7,12]]pentadeca-3,5,7,9,11-pentaene-4-carboxylate (110 g, 313.24 mmol, 1.00 equiv) in methanol/NaOH (40%) (1000 mL). The resulting solution was heated to reflux for 1.5 hours and concentrated under vacuum. Hydrogen chloride (2 mol/L) was used to adjust the pH to 4. The precipitates were collected by filtration, washed with 1×1000 mL of water and dried to afford 91 g (86%) of 9-bromo-10-fluoro-2,5-diazatetracyclo[11.1.1.0[2,6].0[7,12]]pentadeca-3,5,7,9,11-pentaene-4-carboxylic acid as a white solid.

Provenance & Evidence