Triethylamine → 5-Chloro-7-fluoro-1,3-dihydro-1-methyl-2H-1,4-benzodiazepin-2-one

Participants

Reaction Conditions

Reaction Steps

As illustrated in the scheme above, 7-fluoro-3,4-dihydro-1-methyl-1H-1,4-benzodiazepine-2,5-dione (0.495 g, 2.38 mmol) was suspended in POCl3 (10.6 mL) and heated at 100° C. for 30 min. The reaction was cooled and concentrated in vacuo. Traces of POCl3 were removed by adding toluene and concentrating the mixture in vacuo (2×). The residue was dissolved in CH2Cl2, the solution was cooled to 0° C., and Et3N (0.75 mL, 5.4 mmol) was added dropwise. The mixture was stirred for 0.5 h and allowed to slowly warm to room temperature, and was then concentrated in vacuo once again. The residue was purified by silica gel column chromatography (9:1 CH2Cl2:EtOAc+0.5% Et3N) to provide the title compound as a light tan solid (0.422 g, 78%). 1H-NMR (CDCl3): δ 7.53-7.48 (m, 1H), 7.34-7.24 (m, 2H), 4.66 (br s, 1H), 3.72 (br s, 1H), 3.39 (s, 3H). MS (ESI) (M+H)+=227.

Provenance & Evidence