Dimethylformamide → 5-formyl-1-methyl-1H-pyrrole-3-carbonitrile

Temperature

-45 °C

1-Methylpyrrole-2-carbaldehyde (10 g, 91.6 mmol) was dissolved in acetonitrile (100 ml) and cooled to -45° C. Chlorosulfonyl isocyanate (38.9 g, 274.9 mmol) in acetonitrile (40 ml) was added dropwise over 40 min. The mixture was then stirred at room temperature for 12 h. After dropwise addition of dimethylformamide (35 ml), the mixture was heated at 50° C. for 1 h. After cooling to room temperature, the reaction mixture was added to ice (200 ml) and 2N sodium hydroxide solution (286 ml). The precipitate which formed was filtered off with suction. The filtrate were [sic] extracted with diethyl ether. The combined ether phases were washed with dilute sodium bicarbonate solution and water until neutral and dried over sodium sulfate. The solvent was distilled off under water pump vacuum, and the residue was combined with the previously obtained precipitate. Recrystallization from petroleum ether afforded 4-cyano-1-methylpyrrole-2-carbaldehyde (4.3 g) (see, for example, C. E. Loader et al. Can. J. Chem. 59 (1981) 2673-6).

1. temperaturethe mixture was heated at 50° C. for 1 h
2. temperatureAfter cooling to room temperature
3. customThe precipitate which formed
4. filtrationwas filtered off with suction
5. extractionextracted with diethyl ether
6. washThe combined ether phases were washed with dilute sodium bicarbonate solution and water until neutral and
7. dry with materialdried over sodium sulfate
8. distillationThe solvent was distilled off under water pump vacuum
9. customRecrystallization from petroleum ether

ORD record

ord-200ad9210eb14ff69bc1cd820d8bdf21

Source dataset

uspto-grants-2000_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06114358