[CH3:1][NH2:2].[C:3]([C:7]1[CH:23]=[CH:22][CH:21]=[CH:20][C:8]=1[O:9][C:10]1[C:15]([N+:16]([O-:18])=[O:17])=[CH:14][CH:13]=[C:12](Cl)[N:11]=1)([CH3:6])([CH3:5])[CH3:4].[Cl-]>O1CCOCC1.O>[C:3]([C:7]1[CH:23]=[CH:22][CH:21]=[CH:20][C:8]=1[O:9][C:10]1[N:11]=[C:12]([NH:2][CH3:1])[CH:13]=[CH:14][C:15]=1[N+:16]([O-:18])=[O:17])([CH3:6])([CH3:5])[CH3:4]Methylamine (280 μL, 0.56 mmol) was added into a solution of 136b (157 mg, 0.51 mmol) in 1,4-dioxane at 0° C. (1 mL) over 1 h and the resulting reaction mixture was stirred at rt. After 72 h, 40% of the starting chloride remained by HPLC. Another 1.1 eq of methylamine was added at −10° C. over 30 min. The reaction was allowed to warm to rt, stir for 30 min and was then diluted with water (1 mL) and extracted with ethyl acetate (3×1 mL). The combined organic layer was washed with brine (1 mL), dried over sodium sulfate, and concentrated to give a yellow oil. The oil was purified by SiO2 chromatography (12 g) using a gradient of ethyl acetate in hexanes to afford 136c (94 mg, 61% yield) as a yellow oil; HPLC purity 100%, 3.76 min (Method A); [M+H]+=302.24.
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