Sodium Hydroxide → HCID 57939018, compound

Participants

Reaction Conditions

Reaction Steps

2-(6,7-difluoro-1H-benzimidazol-1-yl)ethanol (2.96 g, 15 mmol) is taken into 75 ml of MeCN and sodium phosphate buffer (56 ml, 0.67 M, pH 6.8) and the mixture is heated to 42° C. TEMPO (165 mg, 1.05 mol) is added followed by the simultaneous dropwise addition of a solution of NaClO2 (3.38 g, 80% pure, 30 mmol in 15 ml water) and a solution of bleach (350 μL of 6% NaOCl in 7.5 mL water) over 1.5 hours. After 48 hrs, the same quantities of NaClO2 and bleach are added. After a further 24 hours, TEMPO (165 mg, 1.05 mol) is added and the reaction is stirred for 72 hrs. The darkened reaction is allowed to cool to room temperature followed by the dropwise addition of 30 ml of a saturated solution of Na2SO3 (exothermic). The reaction becomes almost colourless. Using 2 N NaOH, the pH is raised to 9.2 and the reaction is extracted 4 times with ethyl acetate. The pH is then lowered to 3.8 with 2 N HCl and the solution allowed to stand for 48 hours. 1.98 grams of white crystalline material is recovered. The mother liquor is reduced to half the volume and allowed to stand. A further 260 mg is collected. (Combined yield 2.23 g, 70%)

Provenance & Evidence