6-Amino-3-chloropyridazine → 3-Amino-4-bromo-6-chloropyridazine

To a 250 mL round-bottomed flask was added 6-chloropyridazin-3-amine (3.92 g, 30.3 mmol), sodium bicarbonate (5.08 g, 60.5 mmol) and ethanol (20 mL). To the resulting solution, bromine (1.559 mL, 30.3 mmol) was added dropwise. The resulting mixture was stirred at room temperature for 16 hours. The solution was filtered and then concentrated in vacuo. The residue was dissolved in water, and the product extracted with ethyl acetate (3 times). The organic layers were combined, dried over anhydrous sodium sulfate and concentrated in vacuo to give 1A (4.5 g, 71.3% yield). HPLC: Rt=1.25 min (Waters Sunfire C18 column (4.6×50 mm). 10-90% aqueous methanol containing 0.1% TFA, 4 min gradient, flow rate=4 mL/min, detection at 254 nm). MS (ES): m/z=207.88 [M+H]+.

1. filtrationThe solution was filtered
2. concentrationconcentrated in vacuo
3. dissolutionThe residue was dissolved in water
4. extractionthe product extracted with ethyl acetate (3 times)
5. dry with materialdried over anhydrous sodium sulfate
6. concentrationconcentrated in vacuo

ORD record

ord-05b5fa18fba14ca9bc306869c11f3f97

Source dataset

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08252795B2