Sulfamic Acid → 5H-pyrrolo[2,3-b]pyrazine-7-carboxylic acid

Participants

Reaction Steps

To a solution of 2-(1-ethyl-1H-pyrazol-4-yl)-5-((2-(trimethylsilyl)ethoxy)methyl)-5H-pyrrolo[2,3-b]pyrazine-7-carbaldehyde (1.12 g, 3.01 mmol) in 1,4-dioxane (50 mL) and H2O (10 mL) at 0° C. was added sulfamic acid (1.76 g, 18.1 mmol). Then added a solution of NaClO2 (0.44 g, 3.92 mmol) and KH2PO4 (4.92 g, 36.2 mmol) in H2O (30 mL) via dropping funnel over 15 min. The ice bath was removed and the yellow cloudy reaction mixture was stirred at room temperature for 2.5 h. The reaction mixture was diluted with H2O and extracted with EtOAc (2×). The combined organic layers were dried over MgSO4 and concentrated to an oily yellow solid which was triturated with 5% EtOAc/hexanes to afford 1.05 g (90%) of 2-(1-ethyl-1H-pyrazol-4-yl)-5-(2-(trimethylsilyl)ethoxy)methyl)-5H-pyrrolo[3,2-b]pyrazine-7-carboxylic acid as a light yellow solid.

Provenance & Evidence