(2,4-Difluoro-phenyl)-hydrazine → 9-Chloro-2-[2-(2,4-difluoro-phenyl)-2H-[1,2,4]triazol-3-yl]-4,5-dihydro-6-oxa-1-thia-10-aza-benzo[e]azulene

Participants

Reaction Conditions

Reaction Steps

To a suspension of 9-Chloro-4,5-dihydro-6-oxa-1-thia-10-aza-benzo[e]azulene-2-carboxylic acid amide (22 g, 76.8 mmol) in dry toluene (250 mL) was added DMA-DMF (56.1 g, 471.4 mmol). The resulting mixture was heated to 90° C. for 2 h. After removal of the solvent and excess of DMA-DMF, the residue (13.6 g, 94.3 mmol) was dissolved in acetic acid (250 mL) and (2,4-difluorophenyl)hydrazine (16.6 g, 115.2 mmol) was added into the mixture. The mixture was stirred at 90° C. for 2 hours. After removal of the solvents, the residue was treated with EtOAc-water (500 mL, 5:1 (v/v)). The mixture was neutralized with sodium bicarbonate aqueous solution until pH=7. The suspension was filtered and the solid was washed with EtOAc (500 mL). The combined organic layers were washed with saturate sodium bicarbonate aqueous solution (300 mL), dried over sodium sulfate and filtered. The filtrate was concentrated to the crude product, which was purified by flash column (EtOAc/Hexanes=1:3) to give 9-Chloro-2-[2-(2,4-difluoro-phenyl)-2H-[1,2,4]triazol-3-yl]-4,5-dihydro-6-oxa-1-thia-10-aza-benzo[e]azulene (21.4 g, yield: 67%)1H NMR (DMSO, 400 MHz): δ8.35 (s, 1H), 7.98-7.48 (m, 4H), 7.39 (d, J=8.8 Hz, 1H), 7.05 (s, 1H), 4.38 (t, J=4.4 Hz, 2H), 3.2 (t, J=4.4 Hz, 2H). LC-MS (ESI): m/z=417 [M+H]+

Provenance & Evidence