2-benzyloxycarbonylamino-3-[1-(2-trimethylsilanyl-ethanesulfonyl)-1H-indol-5-yl]-acrylic acid methyl ester → (+/-)-2-Amino-3-[1-(2-trimethylsilanyl-ethanesulfonyl)-1H-indol-5-yl]-propionic Acid Methyl Ester

Participants

Reaction Steps

To a flame dried 500 mL of round bottom flask was added 2-benzyloxycarbonylamino-3-[1-(2-trimethylsilanyl-ethanesulfonyl)-1H-indol-5-yl]-acrylic acid methyl ester (2.24 h, 4.36 mmol), methanol (100 mL) and 10% palladium on charcoal (0.52 g). The mixture was degassed and purged with hydrogen five times. It was stirred at room temperature for 1 h and filtered through a pad of celite. Solvents were removed and the residue was subjected to flash chromatography using ethyl acetate/hexanes (1:1 and 2:1) containing 1% triethylamine to afford the tile compound as a colorless viscous liquid (1.27 g, 76%), which solidified upon cooling. 1H-NMR (CD3CN, 500 MHz) δ 7.82 (d, J=8.2 Hz, 1H), 7.51-7.49 (m, 2H), 7.22 (dd, J=8.6, 1.5 Hz, 1H), 6.72 (d, J=3.7 Hz, 1H), 3.70 (dd, J=7.3, 6.1 Hz, 1H), 3.65 (s, 3H), 3.38-3.34 (m, 2H), 3.08 (dd, J=13.4, 5.8 Hz, 1H), 2.95 (dd, J=13.4, 7.3 Hz, 1H), 0.82-0.79 (m, 2H), −0.05 (s, 9H). 13C-NMR(CDCl3, 125 MHz) δ 176.0, 134.4, 133.4, 131.1, 127.9, 126.4, 122.4, 113.1, 107.7, 56.6, 51.7, 50.8, 41.3, 10.1, −2.7. Mass spec. 383.16 (MH)+.

Provenance & Evidence