Triethylamine → 2,1,3-Benzoxadiazol-5-amine

Participants

Reaction Conditions

Reaction Steps

To a solution of 2,1,3-benzoxadiazole-5-carboxylic acid (102 mg, 0.621 mmol) in THF (3 mL) was added triethylamine (103 μL, 0.739 mmol) followed by DPPA (160 μL, 0.739 mmol) at room temperature. The mixture was stirred for 4 h, diluted with CH2Cl2 and washed with water. The organic layer was dried over MgSO4, concentrated and purified by flash chromatography on silica gel with 0 to 50% EtOAc in CH2Cl2. The resulting material was dissolved in AcOH (2 mL) and water (0.7 mL) was added dropwise yielding a slightly cloudy solution which was heated at 105° C. for 30 min. The mixture was cooled, made basic with sat. Na2CO3 solution and extracted several times with THF. The combined organic layers were dried over MgSO4, concentrated and purified by flash chromatography on silica gel eluting with 0 to 15% MeOH in CH2Cl2 to give 34 mg (41%) of compound 480A as a yellow solid. HPLC: 100% at 1.27 min (retention time) (YMC S5 ODS column, 4.6×50 mm Ballistic, 10–90% aqueous methanol over 4 min containing 0.2% H3PO4, 4 mL/min, monitoring at 220 nm). MS (ES): m/z 136.0 [M+H]+.

Provenance & Evidence