反应详情

Step A-4. To a stirred solution of 3-azido-5-chlorophenylcarbamic acid, 1,1-dimethylethyl ester, (A-3, 1.26 g, 4.67 mmol) in 11 mL of dichloromethane is added 11 mL of trifluoroacetic acid. The reaction mixture is stirred at 20°-25° C. for 15 minutes and then concentrated. The residue is diluted with dichloromethane (250 mL) and washed with saturated aqueous NaHCO3 (1×75 mL). The organics are dried (MgSO4), filtered and concentrated. The organic residue is purified by flash chromatography using 20% ethyl acetate in hexane to afford 0.724 g of 3-azido-5-chloroaniline. (A-4, X is Cl). IR (mull) 3474, 3378, 2926, 2141, 2115, 1632, 1603, 1586, 1320, 1268, 1257, 880 cm-1 ; 1H NMR (CDCl3) δ6.42 (m, 2 H), 6.17 (m, 1 H), 3.81 (bs, 2 H); 13C NMR (CDCl3) δ148.5, 142.1, 135.9, 111.6, 109.1,103.5; Mass Spec (70eV, EI) m/z 168 (parent), 140, 107, 78 (base), 63, 52, 37; Exact Mass calculated for C6H5ClN4 : 168.0203. Found: 168.0193.

1. concentrationconcentrated
2. additionThe residue is diluted with dichloromethane (250 mL)
3. washwashed with saturated aqueous NaHCO3 (1×75 mL)
4. dry with materialThe organics are dried (MgSO4)
5. filtrationfiltered
6. concentrationconcentrated
7. customThe organic residue is purified by flash chromatography