Triethylamine → [5-(2,3-Dichloroindol-1-yl)-1,3-dimethyl-6-oxo-pyridazin-4-yl]isopropylsulfanylformate

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Reaction Steps

To a stirred suspension of 4-(2,3-dichloroindol-1-yl)-2,6-dimethyl-pyridazine-3,5-dione (120 mg, 0.370 mmol) in dichloromethane (8 mL) at RT is added triethylamine (129 μL, 0.925 mmol). The reaction mixture turned homogeneous. S-Isopropyl chlorothioformate (69 μL, 0.555 mmol) is added and the reaction mixture is stirred for 15 min. The mixture is then quenched with water (10 mL) and the layers are separated. The aqueous layer is re-extracted with dichloromethane (10 mL×3) and the combined organics were dried (phase separator cartridge) and concentrated under reduced pressure onto silica. Flash chromatography (combiflash, 0-20% EtOAc/isohexane) afforded the desired product [5-(2,3-dichloroindol-1-yl)-1,3-dimethyl-6-oxo-pyridazin-4-yl]isopropylsulfanylformate (140 mg, 0.328 mmol, 89%) as yellow solid.

Provenance & Evidence