[CH2:1]([O:3][C:4](=[O:13])[CH:5]=[N:6][NH:7][CH2:8][CH2:9][CH2:10][CH2:11][CH3:12])[CH3:2].ClN1C(=O)CCC1=O.[CH2:22]=[CH:23][C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1.C(=O)(O)[O-].[K+]>C(OC(=O)C)C.O>[CH2:8]([N:7]1[CH:23]([C:24]2[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=2)[CH2:22][C:5]([C:4]([O:3][CH2:1][CH3:2])=[O:13])=[N:6]1)[CH2:9][CH2:10][CH2:11][CH3:12]To a magnetically stirred solution of (pentylhydrazono)acetic acid ethyl ester (Intermediate II-1) (35.16 g, 179 mmol) in ethylacetate (450 ml) was added N-chlorosuccinimide (NCS) (26.34 g, 197 mmol) and the resulting mixture was heated at 60° C. for 1 hour in a nitrogen atmosphere. To the reaction mixture was added styrene (41.1 ml, 359 mmol) and potassium bicarbonate (89.8 g, 897 mmol) and water (8 ml). The resulting mixture was heated at 70° C. for 16 hours. The resulting mixture was allowed to attain room temperature, concentrated in vacuo and the resulting residue was chromatographically separated using Sepacore equipment (eluant: dichloromethane/methanol=98/2 v/v) to give ethyl 1-(n-pentyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxylate (Intermediate (V-1) (12.1 g, 22% yield) as an oil. 1H-NMR (400 MHz, CDCl3) δ 0.83 (t, J=7, 3H), 1.13-1.28 (m, 4H), 1.35 (t, J=7, 3H), 1.53-1.67 (m, 2H), 2.89 (dd, J=16 and 13, 1H), 3.01-3.09 (m, 1H), 3.14-3.22 (m, 1H), 3.41 (dd, J=16 and 12, 1H), 4.31 (double (diastereotopic) quartet, J˜7, 2H), 4.63 (dd, J=13 and 12, 1H), 7.27-7.39 (m, 5H).
Wird geladen…
