Dimethylformamide → Ethyl 4-formyl-2-methyl-1H-pyrrole-3-carboxylate

Temperature

0 °C

N,N-dimethylformamide (5.5 mL, 71 mmol) in dichloromethane (126 mL) at 0° C. was treated dropwise with oxalyl dichloride (6 mL, 71 mmol). The mixture was stirred at 0° C. for 30 minutes and then at ambient temperature for 1 hour. The mixture was again cooled to 0° C. and treated with a mixture of Example 1a (20 g, 64.6 mmol) in dichloromethane (126 mL). The reaction mixture was stirred at 0° C. for 2 hours and then at ambient temperature for 48 hours. The reaction mixture was again cooled to 0° C. and slowly quenched with 4 N aqueous sodium hydroxide solution. The mixture was then extracted with ethyl acetate (2×300 mL). The combined organic layers were washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered and concentrated. The residue was triturated with a mixture of 9:1 hexanes/ethyl acetate, filtered, and dried under high vacuum to give 8.67 g (74%) of the title compound.

1. waitat ambient temperature for 1 hour
2. temperatureThe mixture was again cooled to 0° C.
3. stirringThe reaction mixture was stirred at 0° C. for 2 hours
4. waitat ambient temperature for 48 hours
5. temperatureThe reaction mixture was again cooled to 0° C.
6. customslowly quenched with 4 N aqueous sodium hydroxide solution
7. extractionThe mixture was then extracted with ethyl acetate (2×300 mL)
8. washThe combined organic layers were washed with saturated aqueous sodium chloride
9. dry with materialdried over anhydrous magnesium sulfate
10. filtrationfiltered
11. concentrationconcentrated
12. customThe residue was triturated with a mixture of 9:1 hexanes/ethyl acetate
13. filtrationfiltered
14. customdried under high vacuum

ORD record

ord-95f423db1f6a40e2a247b9c1458f8bb2

Source dataset

uspto-grants-2015_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09050346B2