3-bromo-1H-pyrrole-2-carbaldehyde

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 3-bromo-1H-pyrrole-2-carbaldehyde (0.44 g, 2.53 mmol) in tert-butanol (5.0 ml) was added 2-methyl-2-butene/2M in THF (5.09 ml, 48.0 mmol). To the reaction mixture was added sodium phosphate mono-H2O (2.461 g, 17.70 mmol) and sodium chlorite (2.058 g, 22.76 mmol) dissolved in water (5.00 ml) at RT over a period of 15 min. The solution was stirred overnight. The reaction mixture was acidified to pH˜4 with 10% aqueous citric acid and extracted with EtOAc (5×30 mL). The organic layers were combined, dried over sodium sulfate filtered and evaporated. The crude material was triturated with minimal amount of EtOAc to afford 3-bromo-1H-pyrrole-2-carboxylic acid (0.35 g, 73% yield) as a tan solid. The filtrate solution was evaporated to afford an impure mixture of the product as an oil. 1H NMR (400 MHz, DMSO-d6): δ ppm 12.55 (br. s., 1H) 12.00 (br. s., 1H) 6.96 (t, 1H) 6.26 (t, 1H). MS: m/z 188.0 (M−1). extracted with EtOAc (5×30 mL) dried over sodium sulfate filtered evaporated The crude material was triturated with minimal amount of EtOAc

Conditions: temp:0.00; pressure:0.00; stir: