Pyridine → tert-Butyl 5-(4-(4-bromophenyl)butanamido)-2-(ethylthio)benzyl(methyl)carbamate

Participants

Reaction Steps

Oxalyl chloride (0.180 mL, 2.06 mmol) was added dropwise to a suspension of 4-bromophenylbutanoic acid (0.250 g, 1.03 mmol) in DCM (3 mL) containing DMF (1 drop) at rt. After 4 h, the reaction mixture was concentrated in vacuo and coevaporated with toluene. The residue was dissolved in DCM (2 mL) and added dropwise to a solution of 17A (0.300 g, 1.01 mmol), DMAP (0.025 g, 0.2 mmol)and pyridine (1.0 mL, 12.3 mmol) in DCM (2 mL) at rt. The reaction mixture was stirred overnight at rt. The reaction mixture was concentrated in vacuo and the residue was triturated with water and then purified by silica gel chromatography (gradient from 0 to 20% ethyl acetate in hexanes) to give 17B (0.46 g, 88%) as a clear oil that solidified on standing. 1H NMR (400 MHz, CDCl3) δ ppm 1.26 (t, J=7.03 Hz, 3 H) 1.33-1.58 (m, 9 H) 1.96-2.04 (m, 2 H) 2.33 (t, J=7.47 Hz, 2 H) 2.63 (t, J=7.47 Hz, 2 H) 2.63 (t, J=7.47 Hz, 2 H) 2.74-2.93 (m, 3 H) 4.56 (br. s., 2 H) 6.96-7.02 (m, 0.5 H) 7.05 (d, J=8.35 Hz, 2 H) 7.13 (br. s., 0.4 H) 7.28-7.36 (m, 0.8 H) 7.38 (d, J=8.35 Hz, 2 H) 7.60-7.72 (m, 0.4 H) 7.81-7.98 (m, 0.9 H) 8.33 (br. s., 1 H).

Provenance & Evidence