Ethyl-2,4-dioxohexanoate → Ethyl 5-ethyl-1-(4-methylbenzyl)-1H-pyrazole-3-carboxylate
反応式
O=[C:2]([CH2:8][C:9](=O)[CH2:10][CH3:11])[C:3]([O:5][CH2:6][CH3:7])=[O:4].CC1[N:18]([CH2:19][C:20]2[CH:25]=[CH:24][C:23]([CH3:26])=[CH:22][CH:21]=2)[N:17]=C(C(OC)=O)C=1>C(O)(=O)C>[CH2:10]([C:9]1[N:18]([CH2:19][C:20]2[CH:25]=[CH:24][C:23]([CH3:26])=[CH:22][CH:21]=2)[N:17]=[C:2]([C:3]([O:5][CH2:6][CH3:7])=[O:4])[CH:8]=1)[CH3:11]参加物
4
実験手順
A solution of ethyl 2,4-dioxohexanoate (Step 1, 2.0 g, 11.6 mmol) and 4-(methylbenzyl)-hydrazine dihydrochloride (Step 3 of Intermediate A, 2.67 g, 12.8 mmol) in acetic acid (15 mL) was stirred for 4 h at 90° C. After removal of the solvent (rotavapor), the residue was subjected to MPLC (silica, cyclohexane/ethyl acetate 5:1) to afford the title compound as a highly viscous oil (1.93 g, 61%): 1H NMR (400 MHz, CDCl3) δ 7.10 (d, 2H), 6.98 (d, 2H), 6.62 (s, 1H), 5.33 (s, 2H), 4.40 (quart, 2H), 2.48 (quart, 2H), 2.31 (s, 3H), 1.40 (t, 3H), 1.18 (t, 3H); DCI(NH3)-MS m/z 273 (MH)+; HPLC RT (Method I) 4.75 min.