反应详情

温度

44 °C

A suspension of silyl ether 148 (2.518 g, 6.81 mmol) in a solution of 1% HCl in 95% EtOH (desilylation conditions described by Cunico et al., 1980) (90 mL) was stirred at 44° C. for 3 days. The resulting solution was cooled (CO2/acetone), neutralised by dropwise addition of 7M NH3 in MeOH (8 mL) and NaHCO3 (0.10 g, 1.19 mmol) with stirring, and then concentrated to dryness and the residue was chromatographed on silica gel. Elution with 0-1% MeOH/CH2Cl2 firstly gave foreruns, and then further elution with 1.5% MeOH/CH2Cl2 gave (7-methyl-2-nitro-6,7-dihydro-5H-imidazo[2,1-b][1,3]oxazin-7-yl)methanol (149) (1.285 g, 88%) as a pale yellow solid: mp (MeOH/CH2Cl2/hexane) 199-201° C.; 1H NMR [(CD3)2SO] δ 8.03 (s, 1H), 5.22 (t, J=5.7 Hz, 1H), 4.13 (dt, J=12.9, 6.0 Hz, 1H), 4.05 (ddd, J=13.0, 8.1, 5.6 Hz, 1H), 3.54 (dd, J=11.6, 5.5 Hz, 1H), 3.48 (dd, J=11.6, 5.8 Hz, 1H), 2.21 (ddd, J=14.4, 8.1, 5.9 Hz, 1H), 2.00 (dt, J=14.4, 5.8 Hz, 1H), 1.32 (s, 3H). Anal. (C8H11N3O4) C, H, N.

1. stirringwith stirring
2. concentrationconcentrated to dryness
3. customthe residue was chromatographed on silica gel
4. washElution with 0-1% MeOH/CH2Cl2 firstly gave foreruns
5. washfurther elution with 1.5% MeOH/CH2Cl2