[Cl:1][C:2]1[N:3]([C:9]2[C:14]([CH3:15])=[CH:13][CH:12]=[CH:11][C:10]=2[CH2:16]O)[C:4](=[O:8])[N:5]([CH3:7])[N:6]=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C(Br)(Br)(Br)[Br:38]>ClCCl>[Br:38][CH2:16][C:10]1[CH:11]=[CH:12][CH:13]=[C:14]([CH3:15])[C:9]=1[N:3]1[C:2]([Cl:1])=[N:6][N:5]([CH3:7])[C:4]1=[O:8]To a solution of the title compound of Step D (3.0 g, 12 mmol) in dichloromethane (56 mL) cooled to 0° C. under a nitrogen atmosphere was added triphenylphosphine (3.72 g, 14 mmol) followed by carbon tetrabromide (5.9 g, 18 mmol). The mixture was allowed to warm to room temperature and was stirred for 2 h. The mixture was concentrated under reduced pressure and the residue was purified by flash chromatography (2:1 hexanes:ethyl acetate) to afford 3.19 g of the title compound of Step E as a light yellow powder. 1H NMR (CDCl3): δ 7.3-7.39 (m,3H), 4.35 (AB q,2H), 3.56 (s,3H), 2.16 (s,3H).
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