反应详情

Alkylation of (S)-alcohol 162 with 4-bromobenzyl bromide (1.35 equiv.) and NaH (1.55 equiv.) as in Example 2UU above for 3 h, followed by chromatography of the product on silica gel, eluting with CH2Cl2 (foreruns) and then with 1% EtOAc/CH2Cl2, gave (7S)-7-{[(4-bromobenzyl)oxy]methyl}-7-methyl-2-nitro-6,7-dihydro-5H-imidazo[2,1-b][1,3]oxazine (163) (373 mg, 61%) as a white solid: mp (CH2Cl2/hexane) 159-161° C.; 1H NMR (CDCl3) δ 7.46 (dt, J=8.4, 2.1 Hz, 2H), 7.39 (s, 1H), 7.12 (dt, J=8.4, 2.1 Hz, 2H), 4.50 (s, 2H), 4.09 (ddd, J=12.5, 7.0, 5.8 Hz, 1H), 4.01 (ddd, J=12.5, 7.1, 5.9 Hz, 1H), 3.62 (d, J=10.2 Hz, 1H), 3.58 (d, J=10.2 Hz, 1H), 2.37 (ddd, J=14.4, 7.1, 5.9 Hz, 1H), 2.10 (ddd, J=14.5, 7.0, 5.9 Hz, 1H), 1.46 (s, 3H); [α]D27−32.0° (c 1.00, CHCl3); HRFABMS calcd for C15H17BrN3O4m/z [M+H]+ 384.0382, 382.0402. found 384.0374, 382.0393.

1. customabove for 3 h
2. washeluting with CH2Cl2 (foreruns)