Phenylacetic Acid → 4-Benzylpyridazine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

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).

Herkunft & Nachweise