Diethyl cyanophosphonate → 1-tert-Butyl 2-methyl (2S,4S)-4-{[(1-isopropyl-1H-indazol-3-yl)carbonyl]amino}pyrrolidine-1,2-dicarboxylate

Participants

Reaction Steps

To a stirred solution of 1-isopropyl-1H-indazole-3-carboxylic acid (300 mg, 1.47 mmol) and 1-tert-butyl 2-methyl (2S,4S)-4-aminopyrrolidine-1,2-dicarboxylate (396 mg, 1.62 mmol, Bioorg. Med. Chem., 2002, 10, 1399-1415) in N,N-dimethylformamide (15 mL) were added diethyl cyanophosphonate (0.27 mL, 1.76 mmol) and N,N-diisopropylethylamine (0.31 mL, 1.76 mmol) at room temperature. The resulting mixture was stirred for 14 h at the same temperature and concentrated under reduced pressure. The resulting residue was diluted with ethyl acetate (200 mL), and the solution was washed with water (50 mL×2), brine (50 mL), dried over sodium sulfate, and concentrated under reduced pressure. The resulting residue was chromatographed on a column of silica gel eluting with n-hexane/ethyl acetate (3:1) to give 618 mg (98%) of the title compound as a white amorphous solid.

Provenance & Evidence