Citric Acid → 3-broMo-1H-Pyrrole-2-carboxylic acid

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).

1. extractionextracted with EtOAc (5×30 mL)
2. dry with materialdried over sodium sulfate
3. filtrationfiltered
4. customevaporated
5. customThe crude material was triturated with minimal amount of EtOAc

ORD record

ord-a1e4880c2dfd407b95ee1597be53de22

Source dataset

uspto-grants-2012_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08304419B2