Ethanol hydrochloride → 1-(2-Pyrimidinyl)-4-acetyl-5-methylpyrazole

Participants

Reaction Steps

2.42 g of 4-acetyl-1-(2-pyrimidinyl)-5-methylpyrazole, 2.89 g of the compound obtained in the above (1) and 12 ml of a 1N hydrochloric acid/ethanol solution were dissolved in 150 ml of ethanol and heated under reflux for 32 hours. During this period, 10 g of paraformaldehyde was added thereto in portions. The reaction mixture was evaporated and the residue was neutralized by adding an aqueous solution of sodium hydroxide. After extracting with chloroform, the extract was washed with a saturated aqueous solution of sodium chloride and dried over anhydrous sodium sulfate. After evaporating the solvent, the residue was purified by silica gel column chromatography (chloroform:methanol=100:1) to thereby give 2.17 g of the title compound in the form of a solid product. 1H-NMR (CDCl3) δ: 2.67 (t, 4H, J=5 Hz), 2.88 (t, 2H, J=7 Hz), 3.00 (s, 3H), 3.09 (t, 2H, J=7 Hz), 3.21 (t, 4H, J=5 Hz), 6.83 (dd, 1H, J=8, 2 Hz), 6.95 (ddd, 1H, J=8, 2, 1 Hz), 7.03 (t, 1H, J=2 Hz), 7.10 (t, 1H, J=8 Hz), 7.35 (t, 1H, J=5 Hz), 8.15 (s, 1H), 8.86 (d, 2H, J=5 Hz).

Provenance & Evidence