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4-bromo-6,7-dihydro-5H-cyclopenta[b]pyridine[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
90%
Bromine (0.0104 mol) then a solution of sodium nitrite (0.0362 mol) in water (3ml) were added drop wise at -1O0C to a mixture of 6,7-dihydro-5H-l-pyridin-4-amine (0.0112 mol) in aqueous hydrogen bromide (48%) (5ml). The mixture was brought back to 200C. Ice was added. The mixture was basified with concentrated sodium EPO <DP n="50"/>hydroxide and extracted with EtOAc. The organic layer was separated, dried (MgSO4), filtered, and the solvent was evaporated, yielding: 2g (90%) of intermediate 24
With palladium 10% on activated carbon; hydrogen; In methanol; under 1500.15 Torr; for 24.0h;
To a stirred solution of 4-nitro-6,7-dihydro-5H-cyclopenta[b]pyridine-l -oxide (640 mg; 3.37 mmol) in MeOH (20 mL) was added 10% palladium on activated carbon (359 mg; 0.34 mmol). The reaction solution was stirred under hydrogen atmosphere (2 bars) for 24 h. Insolubles were removed by filtration and the cake was washed with MeOH. The combined filtrate was concentrated to dryness to afford 6,7- dihydro-5H-cyclopenta[b]pyridin-4-amine (380 mg) as a light brown solid. (0729) MS m/z (+ESI): 135.2 [M+H]+. (0730) 'H-NMR (400 MHz, DMSO-i delta ppm: 7.77 (d, J = 5.5 Hz, 1H), 6.27 (d, J= 5.5 Hz, 1H), 5.71 (s, 2H), 2.73 (t, J= 7.7 Hz, 2H), 2.64 (t, J = 7.4 Hz, 2H), 1.99 - 1.92 (m, 2H).
phenyl N-(6,7-dihydro-5H-cyclopenta[b]pyridin-4-yl)carbamate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
With triethylamine; In dichloromethane; for 2.0h;
To a solution of <strong>[78183-15-0]6,7-dihydro-5H-cyclopenta[b]pyridin-4-amine</strong> (1000 mg; 7.08 mmol) in DCM (60 mL) was added TEA (2.98 mL; 21.24 mmol) and phenyl chloroformate (1.35 mL; 10.62 mmol). The reaction mixture was stirred for 2 h and was then concentrated to dryness to afford crude phenyl N-(6,7- dihydro-5H-cyclopenta[b]pyridin-4-yl)carbamate (2400 mg; 70% purity) as a yellow solid, which was used in the next step without purification. (0733) MS m/z (+ESI): 255.1 [M+H]+.