反应详情

Hydrolysis of (S)-acetate 161 (426 mg, 1.67 mmol) with K2CO3 in MeOH/water as in Example 2EEE above, followed by chromatography of the product on silica gel, eluting with 0-1% MeOH/CH2Cl2 (forerun), and then with 1-2.5% MeOH/CH2Cl2, gave [(7S)-7-methyl-2-nitro-6,7-dihydro-5H-imidazo[2,1-b][1,3]oxazin-7-yl]methanol (162) (343 mg, 96%) as a pale yellow solid that was used directly in the next step; 1H NMR [(CD3)2SO] δ 8.03 (s, 1H), 5.22 (br t, J=5.7 Hz, 1H), 4.13 (dt, J=13.0, 6.0 Hz, 1H), 4.05 (ddd, J=12.9, 8.1, 5.6 Hz, 1H), 3.54 (dd, J=11.6, 5.4 Hz, 1H), 3.48 (dd, J=11.6, 5.7 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); [α]D27 18.0° (c 1.00, DMF).

1. washeluting with 0-1% MeOH/CH2Cl2 (forerun)