Sodium hydrosulfide → Tert-butyl (6-(3-isopropylisothiazol-5-yl)-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)methylcarbamate

Participants

Reaction Conditions

Reaction Steps

An aqueous mixture of tert-butyl (6-(4-methyl-3-oxopent-1-ynyl)-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)methylcarbamate (0.800 g, 2.33 mmol) and hydroxylamine-O-sulfonic acid (0.263 g, 2.33 mol) in water (8.0 mL) and 1,4-dioxane (8.0 mL) was stirred at 0° C. until complete consumption of the organic starting material was observed. The mixture was then carefully treated with solid sodium bicarbonate (0.196 g, 2.33 mmol), followed by treatment with 1.4 M aqueous sodium hydrosulfide (1.83 ml, 2.56 mmol). The reaction was stirred at room temperature overnight. The reaction mixture was diluted with water (20 mL) and extracted with DCM (40 mL), dried over sodium sulfate, filtered and concentrated in vacuo. The concentrated crude material was dissolved in minimal DCM and was purified via MPLC (eluting with 0-10% MeOH/NH4OH in DCM) to yield tert-butyl (6-(3-isopropylisothiazol-5-yl)-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)methylcarbamate (0.196 g, 22.5% yield) with 82% purity. MS (ESI pos. ion) m/z: 433.0 (M+H). Calc'd Exact Mass for C21H20N8OS: 432.51.

Provenance & Evidence