1,2-Dichloroethane → methyl 5-formyl-1H-pyrrole-2-carboxylate

Anhydrous DMF (7.0 mL, 90.4 mmol) was cooled to 5-10 degrees Centigrade under nitrogen. POCl3 (7.8 mL, 83.7 mmol) was added dropwise to the cooled DMF over a couple of minutes. Dry 1,2-dichloroethane (25 mL) was then added and the solution was cooled to 0-5 degrees Centigrade during the addition of 2 (9.46 g, 75.6 mmol) in dry 1,2-dichloroethane (25 mL). The mixture was then heated to reflux for 15 minutes. The reaction was cooled to room temperature, treated with a mixture of ethyl acetate (60 mL) and water (75 mL), poured into saturated NaHCO3 (350 mL), and separated. The aqueous layer was washed three times with ether, and the combined organic extracts were washed twice with aqueous saturated Na2CO3, dried over Na2SO4, and evaporated under vacuum. The resulting solid was sublimed under reduced pressure (20×10−3 torr) at 60 degrees Centigrade in 3-hour intervals to yield compound 3 (7.79 g, 50.1 mmol, 66%). 1H-NMR (CDCl3): δ 10.57 (br s, 1H), 9.70 (s, 1H), 6.95 (m, 2H), 3.94 (s, 3H).

1. temperatureThe mixture was then heated
2. temperatureto reflux for 15 minutes
3. customseparated
4. washThe aqueous layer was washed three times with ether
5. washthe combined organic extracts were washed twice with aqueous saturated Na2CO3
6. dry with materialdried over Na2SO4
7. customevaporated under vacuum
8. waitThe resulting solid was sublimed under reduced pressure (20×10−3 torr) at 60 degrees Centigrade in 3-hour

ORD record

ord-e36fe68fcbf94454a0dbc730cfdacbc8

Source dataset

uspto-grants-2004_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06696575B2