Phenylacetic Acid → 4-Benzylpyridazine

Temperature

70 °C

To a 70° C. solution of pyridazine (9; 10 g, 0.125 mole) in aqueous H2SO4 (2N, 125 mL) was added AgNO3 (6.37 g, 0.0375 mole). Phenylacetic acid (10; 85.06 g 0.625 mole) was added to the mixture. The reaction mixture was stirred vigorously at 70° C. for 20 minutes and was degassed with a flow of nitrogen for 2 minutes, followed by a slow portionwise addition of ammonium persulfate (85.62, 0.375 mole) with rapid gas evolution. The reaction mixture was then heated at 90° C. for 30 minutes. The reaction mixture was then cooled at room temperature and the solution was extracted with CH2Cl2. A 50% NaOH solution was added to the aqueous phase, which was re-extracted with CH2Cl2 twice. The combined extracts were dried over MgSO4. The solvent was evaporated to dryness and the residue was purified by silica gel chromatography using CH2Cl2/5% methanol as the eluent. The yield of 4-benzylpyridazine (11) obtained was 8.2 g or 39%. MS (ESI+): [M+H]+=171.47; 1H NMR (300 MHz, CDCl3), δ ppm: 4.0 (s, 2H), 7.18-7.4 (m, 6H), 9.02-9.18 (m, 2H).

1. customwas degassed with a flow of nitrogen for 2 minutes
2. temperatureThe reaction mixture was then heated at 90° C. for 30 minutes
3. temperatureThe reaction mixture was then cooled at room temperature
4. extractionthe solution was extracted with CH2Cl2
5. additionA 50% NaOH solution was added to the aqueous phase, which
6. extractionwas re-extracted with CH2Cl2 twice
7. dry with materialThe combined extracts were dried over MgSO4
8. customThe solvent was evaporated to dryness
9. customthe residue was purified by silica gel chromatography

ORD record

ord-62abfacfb8b24310b2b6190bcfb35355

Source dataset

uspto-grants-2014_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08895556B2