Acetic Acid → (E)-7-benzylidene-3-bromo-6,7-dihydro-5H-cyclopenta[b]pyridine

Temperature

145 °C

To a mixture of 3-bromo-6,7-dihydro-5H-cyclopenta[b]pyridine (1.83 g, 9.24 mmol) and potassium acetate (0.980 g, 9.99 mmol) in acetic acid (30 mL, 520 mmol) was added benzaldehyde (1.90 ml, 18.7 mmol). The reaction mixture was heated to 145° C. (oil bath temperature) in a sealed pressure tube for 3 d, cooled to room temperature and additional benzaldehyde (4 mL) and KOAc (1.83 g) were added. The reaction mixture was heated to 145° C. (oil bath temperature) in a sealed pressure tube for 2 d and cooled to room temperature. The reaction mixture was diluted with EtOAc. The organic phase was washed with 5 M NaOH, water and brine and dried over MgSO4. The filtrate was concentrated under reduced pressure and the residue was purified by flash column chromatography on silica gel (5% to 10% EtOAc in heptane) to give (E)-7-benzylidene-3-bromo-6,7-dihydro-5H-cyclopenta[b]pyridine (1.57 g, 5.49 mmol, 59% yield) as a yellow solid. MS m/z=286.0 [M+H]+. Calculated for C15H12BrN 285.0.

1. temperaturecooled to room temperature
2. temperatureThe reaction mixture was heated to 145° C. (oil bath temperature) in a sealed pressure tube for 2 d
3. temperaturecooled to room temperature
4. washThe organic phase was washed with 5 M NaOH, water and brine
5. dry with materialdried over MgSO4
6. concentrationThe filtrate was concentrated under reduced pressure
7. customthe residue was purified by flash column chromatography on silica gel (5% to 10% EtOAc in heptane)

ORD record

ord-272550e06ab349ee8a7e389d4aa65970

Source dataset

uspto-grants-2015_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09085576B2