Pyridine → tert-Butyl N-[(1S)-1-(4-{2-[(2R)-2-methylbut-3-enamido]phenyl}pyridin-2-yl)but-3-en-1-yl]carbamate

Participants

Reaction Steps

To a solution of 45D (1.4 g, 4.12 mmol), (R)-2-methylbut-3-enoic acid (0.58 g, 5.79 mmol) in EtOAc (41.2 ml) was added pyridine (1.001 ml, 12.37 mmol). The reaction was cooled down to 0° C. under Ar and propane phosphonic acid anhydride (4.91 ml, 8.25 mmol) was added dropwise. The reaction was then gradually warmed up to rt over night. The reaction mixture was diluted and washed with sat. aq. NaHCO3, aqueous layer back-extracted with EtOAc, combined EtOAc phase washed with brine, dried over MgSO4, filtered, concentrated. The residue was purified by silica gel chromatography to give the desired product (1.47 g, 85%) as an off white foam. 1H NMR (500 MHz, CHLOROFORM-d) δ 8.65-8.60 (m, 1H), 8.19 (d, J=8.3 Hz, 1H), 7.47-7.36 (m, 2H), 7.24-7.18 (m, 3H), 7.16 (dd, J=5.0, 1.4 Hz, 1H), 5.82-5.62 (m, 3H), 5.10-5.01 (m, 4H), 4.86 (d, J=7.2 Hz, 1H), 3.03 (quin, J=7.2 Hz, 1H), 2.62 (tq, J=14.1, 6.9 Hz, 2H), 1.49-1.36 (m, 9H), 1.25 (d, J=7.2 Hz, 3H). MS (ESI) m/z: 422.1 (M+H)+.

Provenance & Evidence