Dimethylformamide → 3,4-dimethyl-1H-pyrrole-2-carboxaldehyde

To a solution of 0.92 mL (12 mmoles) of N,N-dimethylformamide in 10 mL of 1,2-dichloroethane was added dropwise 1.0 mL (12 mmoles) of phosphorus oxychloride at 0° C. The ice-bath was removed and the reaction mixture was further stirred for 30 min. 3,4-Dimethylpyrrole (960.0 mg, 10 mmoles) was added to the above solution portionwise and the reaction mixture was stirred at 50° C. for 5 h. The reaction mixture was poured into ice-cold 1N sodium hydroxide solution (pH=9 after mixing) and the resulting mixture was stirred at room temperature for 1 h. The organic layer was separated and the aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with brine until pH=7, dried over anhydrous sodium sulfate and evaporated. The residue was chromatographed on a silica gel column eluting with a solvent mixture of ethyl acetate and hexane to afford 610 mg (50%) of the title compound.

1. customThe ice-bath was removed
2. stirringthe reaction mixture was stirred at 50° C. for 5 h
3. stirringthe resulting mixture was stirred at room temperature for 1 h
4. customThe organic layer was separated
5. extractionthe aqueous layer was extracted with ethyl acetate
6. washThe combined organic layer was washed with brine until pH=7
7. dry with materialdried over anhydrous sodium sulfate
8. customevaporated
9. customThe residue was chromatographed on a silica gel column
10. washeluting with a solvent mixture of ethyl acetate and hexane

ORD record

ord-a1b360f0bff8425180fb21395b856871

Source dataset

uspto-grants-1998_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05834504