Ammonium Chloride → HCID 88920474, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of (S,Z)-N-(7-bromo-3-chloro-5H-chromeno[2,3-c]pyridin-5-ylidene)-2-methylpropane-2-sulfinamide (3000 mg, 7.25 mmol) in THF (25 mL) was slowly added 2-tert-butoxy-2-oxoethylzinc chloride (0.5 M in diethyl ether, 36.3 mL, 18.13 mmol) in an ice bath. The mixture was stirred at 0° C. for 25 mins, then 80 mL of saturated NH4Cl aqueous solution was added to quench the reaction. The reaction mixture was extracted with EtOAc (2×35 mL). The organic extract was washed with saturated NaCl aqueous solution, dried over MgSO4, filtered and concentrated to give the crude material as an orange solid. The crude material was absorbed onto a plug of silica gel and purified by chromatography through a Redi-Sep pre-packed silica gel column (80 g), eluting with a gradient of 0% to 20% to 50% DCM/MeOH (90/10) in DCM. The fractions which contain mixture were repurified using 40 g Redi-Sep pre-packed silica gel column and eluting with a gradient of 0% to 20% to 50% DCM/MeOH (90/10) in DCM. The desired fractions were collected and concentrated to provide tert-butyl 2-((S)-7-bromo-3-chloro-5-((S)-1,1-dimethylethylsulfinamido)-5H-chromeno[2,3-c]pyridin-5-yl)acetate (isomer A, high Rf), and tert-butyl 2-((R)-7-bromo-3-chloro-5-((S)-1,1-dimethylethylsulfinamido)-5H-chromeno[2,3-c]pyridin-5-yl)acetate (isomer B, low Rf) as off-white solid. Isomer A: 1H NMR (400 MHz, DMSO-d6) δ ppm 0.97 (s, 9 H) 1.03 (s, 9 H) 3.42 (s, 2 H) 6.41 (s, 1 H) 7.15 (d, J=8.71 Hz, 1 H) 7.52 (dd, J=8.80, 2.35 Hz, 1 H) 7.79 (s, 1 H) 7.98 (d, J=2.45 Hz, 1 H) 8.37 (s, 1 H). Isomer B: 1H NMR (400 MHz, DMSO-d6) δ ppm 0.97 (s, 9 H) 1.04 (s, 9 H) 3.34 (s, 1 H) 3.42 (s, 1 H) 6.35 (s, 1 H) 7.16 (d, J=8.80 Hz, 1 H) 7.54 (dd, J=8.80, 2.45 Hz, 1 H) 7.77 (d, J=2.35 Hz, 1 H) 7.95 (s, 1 H) 8.35 (s, 1 H).

Provenance & Evidence