Methanol → Methyl 6-chloropyridazine-3-carboxylate

Oxalyl chloride (1.14 mL, 13.09 mmol), was added dropwise to an ice-cold suspension of 6-chloro-pyridazine-3-carboxylic acid [(1.9 g, 11.9 mmol), J. Het. Chem. 29(6), 1583-92; 1992] in a mixture of dichloromethane (50 mL) and N,N-dimethylformamide (1 drop) and the mixture was stirred for 1 hour at room temperature. The reaction mixture was then evaporated under reduced pressure and the residue was diluted with dichloromethane (30 mL) and cooled to 0° C. Methanol (485 μL, 11.9 mmol) was added and the mixture was stirred at 0° C. for 1 hour. Sodium hydrogen carbonate solution was then added to the reaction mixture and the aqueous layer was separated and extracted with dichloromethane (×2). The combined organic solutions were washed with brine, dried over sodium sulfate and concentrated in vacuo to afford the title compound as a white solid in 65% yield, 1.33 g.

1. customThe reaction mixture was then evaporated under reduced pressure
2. additionthe residue was diluted with dichloromethane (30 mL)
3. temperaturecooled to 0° C
4. stirringthe mixture was stirred at 0° C. for 1 hour
5. customthe aqueous layer was separated
6. extractionextracted with dichloromethane (×2)
7. washThe combined organic solutions were washed with brine
8. dry with materialdried over sodium sulfate
9. concentrationconcentrated in vacuo

ORD record

ord-dda68b37c44b4ec6986e2b8cd03b57be

Source dataset

uspto-grants-2011_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07875615B2