Cl.[CH:2]([NH2:4])=[NH:3].[O-]CC.[Na+].CN([CH:12]=[C:13]1[CH2:17][N:16](C(C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[CH2:15][C:14]1=O)C>C(O)C.C(OCC)(=O)C>[N:3]1[C:14]2[CH2:15][NH:16][CH2:17][C:13]=2[CH:12]=[N:4][CH:2]=1To a solution of formamidine hydrochloride (190 mg) in anhydrous ethanol (25.0 mL) under nitrogen were added sodium ethoxide (21% wt in ethanol, 1.2 mL) and 4-[(dimethylamino)methylene]-1-tritylpyrrolidin-3-one (300 mg, prepared as described for Step B, Intermediate 4). The mixture was refluxed at 80° C. for 8 h. The reaction mixture was cooled to ambient temperature and diluted with ethyl acetate. The organic layer was washed sequentially with 5% aqueous citric acid solution and brine, dried over anhydrous sodium sulfate, filtered, concentrated. The crude residue was deprotected by treatment with 4N methanolic hydrogen chloride for 2.5 h. The mixture was concentrated and the residue purified by chromatography on a Biotage® system (silica, gradient 15% to 25% of 10% concentrated ammonium hydroxide in methanol/dichloromethane) to give the title compound. LC-MS=243.1 (M+1).
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