Tetrabutylammonium Fluoride → (S)-4-(3-Hydroxy-2-methylpropyl)-6-methyl-4H-benzo[1,4]oxazin-3-one

Participants

Reaction Steps

The compound (S)-4-[3-(tert-butyldimethylsilanyloxy)-2-methylpropyl]-6-methyl-4H-benzo[1,4]oxazin-3-one (101IS60-1) (1.0 g, 2.9 mmol) was dissolved in dry THF (12 mL) and TBAF (1.2 g, 3.8 mmol) was added. The reaction was stirred at rt overnight and the solution was concentrated under reduced pressure, the remaining oil was diluted with EtOAc (60 mL) and washed with brine (3×30 mL), dried (Na2SO4) filtered and concentrated under reduced pressure. The remaining oil was purified by flash chromatography (SiO2; Heptane/EtOAc 30:70) to yield an oil which crystallized upon standing (0.69 g, 76%). 1H NMR (CDCl3) δ 6.88 (d, J=8.4 Hz, 1H), 6.83-6.78 (m, 2H), 4.59 (brs 2 H), 4.22 (dd, J=10.0, 14.4 Hz), 3.57-3.38 (m, 3H), 2.9 (vbrs, 1H), 2.33 (s, 3H), 2.04 (m, 1H), 1.08 (d, J=7.2 Hz); 13C NMR (CDCl3) δ 165.7, 143.4, 132.3, 124.9, 117.1, 115.9, 67.6, 63.7, 43.5, 34.2, 21.3, 15.1.

Provenance & Evidence