Br[C:2]1[CH:8]=[C:7]([N+:9]([O-:11])=[O:10])[CH:6]=[CH:5][C:3]=1[NH2:4].[C:12]([CH:14]1[CH2:16][CH2:15]1)#[CH:13]>C(N(CC)CC)C.[Cu]I.Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1>[CH:14]1([C:12]#[C:13][C:2]2[CH:8]=[C:7]([N+:9]([O-:11])=[O:10])[CH:6]=[CH:5][C:3]=2[NH2:4])[CH2:16][CH2:15]1To a deoxygenated solution of 2-bromo-4-nitroaniline (2.17 g, 0.01 mmol), ethynyl-cyclopropane (1 g, 15 mmol) and CuI (10 mg, 0.05 mmol) in triethylamine (20 mL) was added Pd(PPh3)2Cl2 (210 mg, 0.3 mmol) under N2. The mixture was heated at 70° C. and stirred for 24 hours. The solid was filtered off and washed with EtOAc (50 mL×3). The filtrate was evaporated under reduced pressure, and the residue was purified by column chromatography on silica gel (petroleum ether/ethyl acetate=10/1) to give 2-(cyclopropylethynyl)-4-nitroaniline (470 mg, 23%). 1H NMR (300 MHz, CDCl3) δ 8.14 (d, J=2.7 Hz, 1H), 7.97 (dd, J=2.7, 9.0 Hz, 1H), 6.63 (d, J=9.0 Hz, 1H), 4.81 (brs, 2H), 1.55-1.46 (m, 1H), 0.98-0.90 (m, 2H), 0.89-0.84 (m, 2H).
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