Dimethylformamide → HCID 54457812, compound

Participants

Reaction Steps

A solution of 158 mg (0.37 mmol) of the intermediate obtained in Step K in 2.5 mL of methylene chloride and 0.5 mL of dimethylformamide was treated with 112 mg (0.55 mmol, 1.5 eq) of N-t-butoxycarbonyl-2-methylalanine, 0.21 mL of triethylamine (149 mg, 1.48 mmol, 4 eq.), and 261 mg (0.59 mmol, 1.6 eq) of benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate. The mixture was stirred at room temperature for 2 hours, then diluted with 20 mL of ethyl acetate and washed three times with 5% aqueous citric acid, twice with saturated aqueous sodium bicarbonate and once with saturated aqueous sodium chloride. The organic layer was removed, dried over magnesium sulfate, filtered and the filtrate concentrated under vacuum. The residue was purified by silica gel chromatography on silica, eluting with methylene chloride/methanol/ammonium hydroxide (96:3.5:0.5), to afford 250 mg (0.41 mmol, 111%) of the product as a white solid, contaminated with residual solvent. FAB-MS: calculated for C35H43N505 613; found 614 (M+H,25%), 514 (M-BOC, 100%).

Provenance & Evidence