Trifluoroacetic anhydride → HCID 58137374, compound

3,4-Diethoxy-6-methylpyridazine 1-oxide (1.44 g) was initially charged in dichloromethane (50 ml) and admixed dropwise at RT with trifluoroacetic anhydride (2.5 ml). After 2.5 h, the mixture was concentrated to dryness and the residue was taken up with ethanol and saturated potassium carbonate solution. After stirring at RT for 4 h, the mixture was concentrated to dryness again and the residue was admixed with water and dichloromethane. Removal of the organic phase was followed by extraction twice more with dichloromethane, and the combined organic phases were dried over magnesium sulfate, filtered and concentrated. The residue was purified twice using silica gel with dichloromethane/methanol as the eluent. The product-containing fractions were combined and dried. 716 mg of the desired product were obtained.

1. concentrationthe mixture was concentrated to dryness
2. concentrationthe mixture was concentrated to dryness again
3. customRemoval of the organic phase
4. extractionwas followed by extraction twice more with dichloromethane
5. dry with materialthe combined organic phases were dried over magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated
8. customThe residue was purified twice using silica gel with dichloromethane/methanol as the eluent
9. customdried

ORD record

ord-3dcfb6ad95974df29e5c5834076b3228

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08598177B2