Ethylvanillin → 4-(3-Ethoxy-4-hydroxy-phenyl)-1-(2-ethyl-phenyl)-1,4,5,7-tetrahydro-pyrazolo[3,4-b]pyridin-6-one

Participants

Reaction Conditions

Reaction Steps

To 2-(2-Ethyl-phenyl)-2H-pyrazol-3-ylamine 3 (25.9 mmol) in EtOH (150 mL) was added 3-Ethoxy-4-hydroxy-benzaldehyde 5 (28.5 mmol), followed by Meldrum's Acid 4 (28.5 mmol). The reaction mixture was heated to 75° C., then after 2 hours, the reaction mixture was cooled to room temperature, and concentrated under reduced pressure. The residue was treated with water (100 mL) and the product was extracted with dichloromethane (200 mL). The organic extract was dried over anhydrous magnesium sulfate and the solvent was removed at reduced pressure. The residue was purified by column chromatography t to provide (11 mmol) of 4-(3-Ethoxy-4-hydroxy-phenyl)-1-(2-ethyl-phenyl)-1,4,5,7-tetrahydro-pyrazolo[3,4-b]pyridin-6-one 6. 1H NMR (300 MHz, CDCl3/TMS) δ 7.44-7.35 (m, 3H), 7.30-7.25 (m, 2H), 5.57 (d, J=2.1 Hz, 1H), 3.57 (br s, 2H), 2.49 (q, J=7.6 Hz, 2H), 1.10 (t, J=7.6 Hz, 3H); 13C NMR (75 MHz, CDCl3/TMS) δ 145.20, 142.60, 139.62, 135.93, 129.47, 129.41, 127.88, 126.55, 88.70, 24.04, 14.34.

Provenance & Evidence