Tetrabutylammonium Fluoride → HCID 57504671, Verbindung

A solution of tetrabutylammonium fluoride (1M in THF) (10.04 mL, 10.04 mmol) was added in one portion to a stirred solution of (S)-2-(tert-butyldimethylsilyloxy)-3-isopropoxy-N-(5-(methylthio)pyridin-2-yl)propanamide (Intermediate AI1) in tetrahydrofuran (50 mL). The resulting solution was stirred at ambient temperature for 30 minutes. The majority of the THF was evaporated in vacuo. The residue was diluted with EtOAc (100 mL), washed sequentially with water (25 mL) and saturated brine (25 mL). The organic layer was dried (MgSO4), filtered and evaporated to afford crude product. The crude product was purified by flash silica chromatography, elution gradient 30 to 50% EtOAc in isohexane to afford the product (2.38 g, 88%). 1H NMR (400 MHz, DMSO) δ 1.03-1.07 (6H, m), 3.28 (3H, s), 3.53-3.64 (3H, m), 4.19-4.22 (1H, m), 5.95 (1H, d), 7.77-7.80 (1H, d), 8.04-8.06 (1H, d), 8.24-8.25 (1H, s), 9.60 (1H, s); m/z (ES+) (M+H)+=271; HPLC tR=1.74 min.