Sulfuric Acid → HCID 22320305, compound

To diethyl ether (200 mL), was added a 20% sodium ethoxide ethanol solution (280 g, 820 mmol) at 0° C., and subsequently was added dropwise diethyl oxalate (19.8 g, 400 mmol), and the mixture was stirred at the same temperature for 30 minutes. To the solution, was added dropwise a solution of acetonitrile (21 mL, 400 mmol) in diethylether (20 mL), and the mixture was allowed to warm to room temperature and stirred at the same temperature for 24 hours. The resulting crystals were collected by filtration. The crystals were suspended in chloroform (400 mL), to which a solution of 2-hydrazinopyridine (34.3 g, 314 mmol) and conc. sulfuric acid (16.7 mL, 314 mmol) in water (300 mL) was added dropwise at room temperature, and the mixture was stirred at the same temperature for 72 hours. The organic layer was separated and the aqueous layer was extracted with chloroform. The organic layers were combined, washed with saturated brine and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue thus obtained was purified by silica gel column chromatography (hexane:ethyl acetate=3:1 to 1:1) to give the title compound (30.0 g, 45% yield).

1. stirringstirred at the same temperature for 24 hours
2. filtrationThe resulting crystals were collected by filtration
3. additionwas added dropwise at room temperature
4. stirringthe mixture was stirred at the same temperature for 72 hours
5. customThe organic layer was separated
6. extractionthe aqueous layer was extracted with chloroform
7. washwashed with saturated brine
8. dry with materialdried over anhydrous magnesium sulfate
9. customthe solvent was evaporated under reduced pressure
10. customThe residue thus obtained
11. customwas purified by silica gel column chromatography (hexane:ethyl acetate=3:1 to 1:1)

ORD record

ord-4f3838b9308f47838bcc15a5ae6a2f4e

Source dataset

uspto-grants-2005_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06949648B2