反应详情

2-(4-Amino-3-cyclopropylmethoxy-phenyl)-4-methyl-pentanoic acid cyclopropylmethyl ester (16.3 g, 49.1 mmol) was dissolved in chloroform (200 mL) and N-chlorosuccinimide (5.3 g, 0.75 equiv, 39.6 mmol) was added. The reaction mixture was refluxed for 1 h and after cooling treated with 10% potassium carbonate solution (100 mL). The reaction mixture was extracted with EtOAc (3×50 mL) and the combined organic phases were dried over magnesium sulfate. Evaporation of the solvent gave the crude product as a brown oil, which was purified by silica gel gradient column chromatography by use of Heptane-EtOAc to give 2-(4-amino-3-chloro-5-cyclopropylmethoxy-phenyl)-4-methyl-pentanoic acid cyclopropylmethyl ester as a yellow oil (5 g, 36%). 1H NMR (300 MHz, CDCl3/TMS): δ 6.85 (s, 1H), 6.66 (s, 1H), 3.95-3.80 (m, 4H), 3.49 (t, J=7.7 Hz, 1H), 1.94-1.82 (m, 1H), 1.63-1.52 (m, 1H), 1.50-1.40 (m, 1H), 1.28-1.18 (m, 1H), 1.11-1.03 (m, 1H), 0.90 (d, J=6.6 Hz, 6H), 0.66-0.58 (m, 2H), 0.53-0.47 (m, 2H), 0.37-0.32 (m, 2H), 0.25-0.20 (m, 2H); 13C NMR (75 MHz, CDCl3/TMS): δ 174.2, 146.8, 132.6, 128.7, 120.6, 118.3, 109.4, 73.6, 69.3, 49.0, 42.6, 25.9, 22.6, 22.4, 10.4, 9.8, 3.3.

1. temperatureThe reaction mixture was refluxed for 1 h
2. temperatureafter cooling
3. extractionThe reaction mixture was extracted with EtOAc (3×50 mL)
4. dry with materialthe combined organic phases were dried over magnesium sulfate
5. customEvaporation of the solvent
6. customgave the crude product as a brown oil, which
7. customwas purified by silica gel gradient column chromatography by use of Heptane-EtOAc